Symptom Management Theory

Abstract

A detailed analysis of Symptom Management Theory (SMT) along with its extent of use and implications for adults with cancer as demonstrated in 20 oncology research studies is reported. SMT provides useful guidance for adult oncology research and nursing practice. Theory dimension most researched in cancer was symptom experience. Although theory assertions were demonstrated in 80% of the studies, it was used to an adequate extent only in 35% of them. Comparisons between cancer-related clinical outcomes with and without use of SMT, certain theory modifications, and future SMT-based studies involving longitudenal designs in this population are warranted.

Symptom management research is a core area of nursing science¹ and one of the priorities of the National Institute of Nursing Research.² It also holds an essential place in oncology. Individuals with cancer struggle with multiple physiological and psychological symptoms^3,4 that rarely occur in isolation but rather present themselves concurrently. For instance, long-term cancer survivors struggle with symptom clusters of fatigue, insomnia, pain, dyspnea, appetite loss, constipation, diarrhea, nausea, and vomiting.⁵ There is thus an emerging focus on studying clusters of symptoms and their relationships, which is vital to developing strategies to manage cancer-related symptoms. Theories of symptom management help nurse researchers organize the intricate conceptual relationships within the symptom experience. One of the earliest conceptual models introduced for symptom management research was the Symptom Management Model, which is now referred to as the Symptom Management Theory (SMT).^6–8 SMT depicts symptom management as dynamic relationships between 3 key concepts or dimensions: symptom experience, symptom management strategies, and symptom outcomes. These dimensions are nested within 3 domains of nursing science (person, environment, and heath/illness) that influence and surround all 3 dimensions of symptoms, thus signifying the contextual considerations for nursing research.^6–8

SMT has been theoretically explored and compared with other theories in past literature.^9–13 For instance, in 2010, Linder¹² analyzed SMT using the process described by Walker and Avant with implications for pediatric oncology research and nursing. However, to the best of investigators’ knowledge, no systematic analysis of SMT with implications for adults with cancer has been conducted. A detailed appraisal on utility of SMT for oncology research and practice in adults is important because the findings will provide a comprehensive understanding of “which” theory concepts and relationships are commonly addressed in oncology research and practice, “what” are the findings of the theory-guided studies, and “where” are the gaps in theory utility. Such an appraisal warrants use of a systematic framework for theory analysis and evaluation. Fawcett and DeSanto-Madeya¹⁴ proposed a distinct set of criteria for theory critique that separated questions for theory analysis (nonjudgmental description of a theory) from those intended for theory evaluation (judgments about the extent to which the theory meets evaluation criteria). This framework was chosen by the investigators for SMT appraisal because of 2 reasons: Fawcett and DeSanto-Madeya¹⁴ propose specific questions for evaluation of middle-range theories; and they emphasize on observability of concepts, potential for measurement, and congruency between theoretical assertions and empirical evidence.¹⁴ Hence, this framework was the best fit, as its systematic approach and emphasis matched with the investigators’ purpose of detailed appraisal of SMT.

A common misconception exists that mention of a particular conceptual model or a theory as “theoretical framework” in research indicates adequate use of that theory.¹⁵ Nurse scholars agree on the need for testing of nursing theories.¹⁶ This testing process involves evaluating whether a theory is adequately used and tested.¹⁶ Silva¹⁵ was the first scholar to describe evaluation criteria for empirical testing of a theory that helped determine the extent or degree to which a theory is used. These original criteria were further expanded by Silva and Sorrell¹⁶ to include 3 additional approaches to theory testing in nursing, wherein criteria were described to verify a theory through critical reasoning, description of personal experiences, and application to nursing practice. The investigators were interested to evaluate “how” SMT has been used in the adult cancer population using Silva and Sorrell’s¹⁶ 4 different theory-testing approaches. Since there has been no analysis of SMT with respect to its extent or degree of use,¹⁵ the investigators considered this aspect important in addition to theory appraisal. Therefore, the aims of this article are to (a) analyze and evaluate SMT using Fawcett and DeSanto-Madeya’s¹⁴ framework, (b) identify the extent to which SMT has been used in research or practice involving adults with cancer using Silva and Sorrell’s criteria,^15,16 and (c) determine the implications of SMT for nursing care and research among adults with cancer.

DATA SOURCES

For this analysis, the investigators used the 3 original expositions by the authors of SMT as the sources of the theory.^6–8 To examine the application of SMT among adults with cancer, the investigators conducted a systematic review of literature in the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Ovid MEDLINE, APA PsycINFO, EMBASE, Google Scholar, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Search terms included symptom management theory OR symptom management model AND cancer. Database-specific customization was done to improve search sensitivity and comprehensiveness. The search had no date limits and included all study designs and languages. Studies relevant to the selected population that referred to SMT or the Symptom Management Model were subjected to title and abstract screening, and ancestry and forward searching were performed on all articles that met the inclusion criteria. Since Dodd et al⁷ were the authors of SMT and are key researchers in oncology symptom management, the investigators also conducted an author search with Dodd to identify cancer-related studies. By following these processes, 28 articles were identified for full-text screening. Two additional eligible studies were found through ancestry and forward searching. The study selection process and the exclusion criteria for each stage of screening are shown in the PRISMA flow diagram¹⁷ (Figure 1). The screening process yielded 22 articles^18–39 that reported findings from 20 studies, with 2 studies represented by articles each on different aspects of the study (Supplemental Digital Content Table 1 available at: http://links.lww.com/ANS/A28).

Figure 1.

PRISMA flowchart illustrating study selection process. SMT indicates Symptom Management Theory.

ANALYSIS OF SMT

The analysis, per Fawcett and DeSanto-Madeya’s¹⁴ framework, involves systematic examination of a theory’s scope, context, and content,¹⁴ as presented in the following sections. This process examines what the authors of the theory have directly written about the theory; indirect inferences and interpretations may also be necessary where aspects of the authors’ writings are not clear.¹⁴

Theory scope

The first step in theory analysis is to classify the theory’s scope as either broad or narrow. SMT, based on the empirical work of its authors, aims to guide symptom management research and clinical practice. The literature review found that between 2000 and 2018, 20 research studies reported use of SMT as a theoretical framework to explore symptom experiences, test intervention strategies, or examine relationships between theoretical dimensions among adults with cancer (Supplemental Digital Content Table 1 available at: http://links.lww.com/ANS/A28).^18–39 This use indicates that the theory’s concepts and relationships can be converted to study variables and testable hypotheses. In addition, the review findings indicate use of SMT in studies that primarily employed quantitative designs and correlational statistics to identify relationships between SMT concepts. These findings support a view of SMT’s scope as an explanatory middle-range theory⁴⁰: it has a specific substantive content pertaining to symptom management.

Theory context

The second step is to examine the context of the theory. This includes scrutinizing certain key areas: nursing metaparadigm concepts and propositions, the theory’s philosophical basis, its conceptual model, and the contribution of antecedent knowledge from nursing and related disciplines to theory development.¹⁴

Nursing metaparadigm concepts and propositions

Three of the 4 nursing metaparadigm concepts—person, health/illness, and environment—were mentioned as variables influencing symptom perception in the first exposition of SMT⁶ yet were fully included in the theory only in 2001,⁷ when they were introduced as “domains of nursing science” to emphasize the context in which the symptom management process occurs. The authors explicitly described the variables within each of these 3 nursing domains and also explained the variables’ direct and indirect effects on the 3 dimensions of symptom management: perception, evaluation, and response to a symptom.⁷ For instance, they explain how the demographic, physiological, psychological, sociological, and developmental variables in the person domain of nursing are intrinsic to the way an individual perceives, interprets, and responds to symptoms. Similarly, the health/illness domain comprises risk factors, health status, and disease or injury variables, and the environment domain includes the physical, social, and cultural environments.⁷ The authors did not explicitly include the fourth nursing metaparadigm concept—nursing process/goals—in the model. However, they revised the theory to guide symptom assessment and treatment in nursing practice and to suggest questions and hypotheses for nursing research.⁸ Therefore, the investigators consider that the domain of nursing goals is indirectly addressed.

SMT also directly or indirectly addresses all 4 nursing metaparadigm propositions: (a) human processes of living and dying; (b) human health experiences within the context of environment; (c) benefits of nursing actions to human beings; and (d) the continuous mutual process of human beings with their environment.¹⁴ First, various theory components are directly or indirectly related to human processes of living. For instance, the physiological, psychological, and developmental variables in the person domain; health status and disease in the health/illness domain; and symptom management outcomes such as functional and emotional status, quality of life, morbidity, and comorbidity all address human processes of living. The theory includes mortality—which relates to the process of dying—as one of the outcomes a person may experience because of the symptom experience and/or symptom management strategies. Second, the SMT authors describe the symptom experience as consisting of an individual’s perception, evaluation, and response to a symptom, and this can be considered as an important health experience. They further explain that the theory’s key concepts and propositions are influenced by the individual’s physical, social, and cultural environments. Third, SMT provides a framework for developing nursing interventions to alleviate symptoms and improve outcomes in patients, which addresses the benefits of nursing actions to the individual. Finally, the authors recognize that individuals experience and manage their symptoms by continually interacting with their specific physical, social, and cultural environments. Thus, the investigators conclude that overall, SMT incorporates all the nursing metaparadigm concepts and propositions.

Philosophical basis

The next key area of context is the philosophical claims upon which a theory is based. Because the authors of SMT do not mention any specific “philosophical claims” or “worldview” in their theory descriptions, a search for indirect inferences was warranted. In describing the origins of the theory, the authors describe the inadequacies in the existing self-care models, narrow focus on symptom management, and lack of frameworks for describing patients’ symptom experiences.^6,8 SMT’s assumptions thus reflect the significance of self-report of symptoms, symptoms in nonverbal patients, and preemptive symptom management strategies.⁷ In addition, SMT is based on the premise that effective management of any symptom or symptoms demands that all 3 dimensions of symptom management be considered within the context of nursing domains.⁶ The investigators infer from the theory’s origin, assumptions, and underlying premise that SMT reflects a worldview in which individuals’ subjective experience of symptoms is considered essential for planning and implementing care. The theory also supports the worldview that symptom management is a dynamic process that is influenced by both symptom outcomes and the nursing domains. The authors’ focus on patients’ experiences, desired outcomes, and dimensions of symptom management within nursing domains implicitly reflects a philosophy of centrality of the person experiencing the health condition and the contextual perspectives of symptom experiences.

Original conceptual model

SMT originated from a conceptual model developed in 1994 by the Symptom Management Faculty Group at the University of California, San Francisco School of Nursing.⁶ The original model, derived through faculty research and practice, intended to provide a framework to allow improved collaboration in symptom research and clinical practice.⁸ Following another set of rigorous testing, collegial discussions, and seminars, the model was updated in 2001 (Figure 2) to guide development and replication of nursing interventions.⁷ This revised model incorporated 5 important changes: the addition of nursing domains (person, environment, and health/illness); the specification of components of symptom management strategies; the addition of cost as an outcome factor; the removal of directional arrows between symptom status and other outcome factors within the symptom outcomes dimension; and the inclusion of adherence. The model was further updated in 2008, leading to alterations in concept labels and the nature of the relationships among the concepts, and was at that time named the “Symptom Management Theory.”⁸

Figure 2.

Symptom Management Model. From Dodd et al.^7(p670) Copyright 2008 by John Wiley & Sons, Inc. Used with permission.

Antecedent knowledge from nursing and related disciplines

Although the authors of SMT made no explicit mention of antecedent knowledge, they developed SMT to address the need for a broader perspective to symptom management than was available at that time. The authors called out a narrow focus on curing the cause of symptoms, an emphasis on isolated aspects of symptom management, applicability limited to the acute care environment, and lack of attention to the symptom experience in existing self-care models as lacunae in contemporary symptom management practice.⁶ In view of these deficiencies, the authors were proposing a new approach to symptoms.

Theory content

The final step in theory analysis focuses on examining the theory’s concepts and propositions and identifying the propositions as relational or nonrelational.¹⁴ Supplemental Digital Content Table 2 (available at: http://links.lww.com/ANS/A29) presents the content of SMT in terms of its concepts, propositions, and nursing domains.

EVALUATION OF SMT

According to Fawcett and DeSanto-Madeya,¹⁴ evaluation of a theory requires judgments about the extent to which it satisfies the criteria of significance, internal consistency, parsimony, testability, empirical adequacy, and pragmatic adequacy. These judgments, described in the following sections, are made only after examining the results of theory analysis and reviews of practical applications of the theory.

Significance

Social and theoretical significance is evaluated on the basis of a theory’s impact on lifestyle, its importance in advancing nursing knowledge, and the explicitness of its origins.¹⁴ SMT focuses on symptom management, which is a socially relevant and essential construct. The authors propose a framework for planning interventions for individuals experiencing undesired or debilitating symptoms, with the purpose of improving outcomes such as functional status and quality of life within the context of individuals’ sociological variables and their physical, social, and cultural environments (Figure 2; Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A29). In addition, because SMT addresses symptom management comprehensively, it can serve as a framework for developing clinical practice guidelines and revising health policies.

SMT has been the basis for multiple nursing studies focusing on symptom experiences and symptom management in cancer.^{18–31,33–39} Findings from these studies have expanded the body of nursing knowledge and advanced the science of symptom research. The review findings support the applicability of SMT concepts to adults with cancer. Research using these concepts offers new insights into oncology nursing practice, which subsequently advances nursing knowledge. Since patients with cancer face various personal and social consequences due to the multiple debilitating symptoms, SMT can serve as a guide to explore symptom experiences, evaluate management strategies, and measure the adverse outcomes. Thus, it can ultimately contribute to reduction in symptom burden and improvement of patient outcomes. The social and theoretical contributions of SMT are thus identifiable.

Significance of a theory is also based on explicitness of concepts and propositions, antecedent knowledge, conceptual model, and philosophical claims.¹⁴ As explained in the “Theory Context” section on Context, SMT’s conceptual origins and metaparadigm concepts are explicitly described, whereas its philosophical basis and antecedent knowledge are only implied.

Given all these observations together, SMT meets Fawcett and DeSanto-Madeya’s¹⁴ criterion of significance.

Internal consistency

The second step of theory evaluation is internal consistency, which focuses on congruency among the elements of a theory’s context and content. This step involves checking for semantic clarity and consistency in theory concepts (eg, theory dimensions such as symptom experience, nursing domains such as person) and structural consistency in theory propositions (eg, relationship between the theory concepts).¹⁴ In terms of semantic clarity, SMT’s concepts are clearly identified and defined by its authors (Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A29). Three dimensions of symptom management and their associated components are well described in the original presentation.^6,7 The addition of the 3 nursing domains and the new concept of adherence during model revision was also accompanied by clear definition and description with examples.⁷ Although slight differences exist in the arrangement of words to define the concepts in later publications, these variances do not affect semantic clarity or consistency. Semantic consistency is evident through consistent use of the same terms and definitions. Definitions were not altered during model revisions; rather, subsequent articles by the SMT authors further clarified the meaning of the concepts. For instance, in their first article, they explained perception of symptoms as “whether an individual notices a change from the way he or she usually feels or behaves.”^6(p273) The same definition appears in all subsequent revisions. The investigators noted one inconsistency in the explanations of the health/illness domain of the theory: the article describing the revised model⁷ explains that the health/illness domain includes variables of “risk factors, injuries, or disabilities,” yet the conceptual model depicts “risk factors, health status, and disease and injury” (see Figure 2). In addition, the revised model depicts “who (delivers)” as one of the components of symptom management strategies, yet no mention is made of this in the text⁷; instead, this is discussed in a later original article by the authors.⁸

SMT displays good structural consistency in that the theory’s propositions are “reasonable.”¹⁴ For instance, the authors postulate the importance and interaction of the components of symptom experience: perception, evaluation, and response. This is a reasonable proposition because it is observed in clinical practice and daily lives that individuals perceive their symptoms depending on their sociodemographic and psychological variables, evaluate the threat posed by these symptoms, and then address these threats through physiological, psychological, and behavioral responses. The authors specify linkages between the concepts and describe both relational and nonrelational propositions (Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A29). Not only are these propositions consistent with one another and the model’s overall structure but also there are no major flaws or contradictions in the exposition of the propositions. In addition, the contents of SMT (its concepts and propositions) are congruent with its context (its philosophical claims) and the conceptual model. The conceptual model explicitly shows the 3 dimensions of symptom experience and their interrelatedness using bidirectional arrows, while overlapping circles represent the 3 domains of nursing (Figure 2). The investigators conclude that SMT satisfies the criterion of internal consistency.

Parsimony

The criterion of parsimony requires a theory to be simple, clear, and concise, without oversimplifying the phenomenon of interest.¹⁴ SMT presents a semblance of parsimony because of its 3 dimensions of symptom management enveloped within the 3 domains of nursing science. However, a closer scrutiny reveals relationships that exist within and between the symptom management dimensions and the influence of the nursing domains (Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A29). These elaborate interrelationships, and the multiple variables within each nursing domain and symptom management dimension, increase the theory’s complexity. Testing of all or parts of SMT is a sophisticated challenge,⁸ which indicates reduced parsimony. However, this complexity can be viewed in contrasting ways. The phenomenon of symptom management itself is complex, and it is challenging merely to reflect all the intricate aspects of this phenomenon in a theoretical structure. Despite this complexity, the authors have been able to explain the various components and interrelationships in SMT, which helps make the theory usable for research and practice. Given this context, reduced parsimony might be considered a trade-off against the risk of oversimplification. On the contrary, the complexity requires that researchers understand the theory’s concepts and propositions in depth and detail to ensure appropriate application.

Testability

The fourth step in theory evaluation focuses on a major characteristic of a scientifically useful theory—its testability.¹⁴ Empirical testability of a middle-range theory involves evaluating whether its concepts are observable and its propositions are measurable. The criterion is met when empirical indicators such as instruments are able to measure the theory’s concepts and data analysis techniques permit measurement of the theory’s propositions.¹⁴ The 20 studies in this review that used SMT for research among adults with cancer have established the testability of SMT concepts to a great extent. Supplemental Digital Content Table 1 (available at: http://links.lww.com/ANS/A28) presents the evidence of testability of SMT in terms of the questionnaires used, the research designs utilized to elicit data, and the statistical tests conducted to measure the theoretical assertions.

All 20 studies operationalized SMT concepts and examined the symptom experience dimension using reliable and valid instruments Supplemental Digital Content Table 1 available at: http://links.lww.com/ANS/A28. These instruments varied across studies, ranging from generic (Symptom Query Questionnaire, Illness Perception Questionnaire, Memorial Symptom Assessment Scale) to symptom- or disease-specific (Brief Fatigue Inventory, Hospital Anxiety and Depression Scale, General Sleep Disturbance Scale, Lung Cancer Symptom Scale). Validated instruments were utilized to assess symptom outcomes in 9 of the studies.^{26,28–31,33,35,37,39} However, the outcomes examined in these 9 studies were restricted to quality of life, functional status, symptom status, and sexual function. Meanwhile, empirical indicators of symptom management strategies were mostly not validated. Barring 2 studies that examined hope as a coping strategy²⁸ and a self-care strategy that used a self-care diary,³⁵ all other studies utilized researcher-prepared questionnaires or Likert scales to examine the dimension of symptom management strategies. Since all the theory concepts and propositions are not tested in the cancer population, this points to incomplete testability and a gap in theory utility. Nevertheless, the theory is derived through rigorous processes involving programs of research among adult patients. Therefore, all the theory components have the potential to be measured.

Researchers used appropriate methodologies to examine the components of symptom management in individuals with cancer. Cross-sectional design was utilized by 55% of the studies, while the rest utilized randomized controlled trial,^29,31,39 longitudinal,^22,35,37 secondary analysis,^26,33 or qualitative designs.²¹ As depicted in Supplemental Digital Content Table 1 (available at: http://links.lww.com/ANS/A28), all the studies used descriptive statistics to describe their sample characteristics and clinical characteristics. Commonly used inferential statistics were t tests, correlations, and regression analyses. Overall, the literature on the use of SMT in adult populations with cancer demonstrates the empirical testability of the theory and the observability and measurability of the theoretical concepts and propositions.

Empirical adequacy

Empirical adequacy requires the theoretical assertions to be congruent with empirical data.¹⁴ As depicted in Supplemental Digital Content Table 1 (available at: http://links.lww.com/ANS/A28), findings from 80% of the studies were congruent with SMT assertions. For instance, SMT’s assertion of relationships between symptom dimensions was empirically demonstrated in 10 studies. Six studies^{26,28,30,31,37,39} supported the theoretical assertion that the dimensions of symptom experience and symptom outcomes are interrelated. Relationships between the dimensions of symptom experience and symptom management strategies were supported by 2 studies,^20,28 while relationships between symptom management strategies and symptom outcomes were demonstrated in 2 other studies.^29,33 Similarly, the theoretical assertion that bidirectional relationships exist within the components of the symptom experience dimension was demonstrated in 5 studies.^{22–24,27,34} The influence of nursing domains on symptom experience and/or symptom outcomes was confirmed in 8 studies.^{20,22,25,27–29,31,37}

However, the investigators also noted certain weaknesses in the review in terms of empirical adequacy. Each study examined a set of SMT concepts and propositions, yet none of the studies tested the theory in its entirety—which is to be expected, given the wide-ranging concepts and relationships included in SMT. For example, Yin et al¹⁸ explored symptom experiences and symptom management strategies in adults with rectal cancer but did not include symptom outcomes. Across the studies, some theoretical propositions were less examined and supported than others. For instance, in adults with cancer, the symptom experience dimension was the most researched aspect of SMT; the relationships between symptom experience and symptom management strategies and those between symptom management strategies and outcomes were understudied. In addition, the variables selected for inclusion from each part of SMT (eg, symptom management dimensions, nursing domains) were not consistent across studies, although the researchers had proposed testing of similar relationships among model components. The lack of a consistent set of variables across studies prevented the investigators from including a meta-synthesis or meta-analysis in our review and evaluation. Finally, since all the studies in the review were theoretically based on SMT, their study findings were interpreted in light of SMT, which risks circular reasoning. None of the studies considered alternative symptom theories for data interpretation. However, we find that, overall, the empirical data do conform to the theoretical assertions, which supports the empirical adequacy of SMT.

Pragmatic Adequacy

Pragmatic adequacy, the final step in theory evaluation, focuses on the theory’s utility for practice. Pragmatic adequacy is determined by reviewing all descriptions of the use of the theory in practice and the extent to which the theory fulfills 7 criteria: education and special skill training required, real-world application in nursing, feasibility of implementation, legal ability for implementation, compatibility with expectations, favorable outcomes, problem-solving effectiveness.¹⁴

Education and special skill training required

SMT has multiple components and interrelationships. Because of this complexity, nurses need to have a full understanding of the theory, including the ability to distinguish between concepts and understand their relationships in the context of the nursing metaparadigm domains, before they attempt to apply SMT in nursing practice. Nurses may thus require additional educational sessions and skill training in appropriate application of SMT. This systematic review found that nurse researchers were able to describe the theory and operationalize the concepts in their studies. Some researchers also used SMT dimensions to develop effective clinical protocols or structured assessment programs, suggesting a good understanding of the theory.

Real-world application in nursing

Among adults with cancer, SMT has been applied as a theoretical framework in 3 ways: for empirical quantitative research, for application in nursing practice, and for describing patient experiences (Tables 1–3). In empirical quantitative research, SMT was used to explore 1 or more dimensions of SMT and the interrelationships between them (Supplemental Digital Content Table 1 available at: http://links.lww.com/ANS/A28 and Table 1). SMT was also used to develop research instruments to explore symptom experiences and management strategies among patients with rectal¹⁸ or bladder¹⁹ cancer and depict individual study models.^20,34,35 In nursing practice, SMT was used as a basis for developing a structured program leading to clinical protocols for symptom assessment^38,39; developing a quality improvement program to improve assessment, information, and management of chemotherapy toxicities^32,36; and developing and testing efficacy of a specialized nursing role³¹ (Supplemental Digital Content Table 1 available at: http://links.lww.com/ANS/A28 and Table 2). Finally, SMT was used as a guide to describe individuals’ symptom experiences and management following sphincter-saving surgery for rectal cancer (Supplemental Digital Content Table 1 available at: http://links.lww.com/ANS/A28 and Table 3).²¹ Overall, findings of this review support the utility and validity of SMT concepts and propositions in real-world nursing research and practice.

Table 1.

Extent of Testing of SMT Through Empirical Deductive Approach¹⁵ Among Adults With Cancer^a (N = 16)

Author (Year)	Criteria 1b	Criteria 2c	Criteria 3d	Criteria 4e	Criteria 5f	Criteria 6g	Criteria 7h	Application of SMT Other Than as Theoretical Framework
Yin et al (2018)18	√	√	√	√	√	√	√	Developed a structured interview guide based on SMT dimension
Vuttanon et al (2017)19	√	√	√	√	√	√	√	Developed a questionnaire based on SMT dimensions and reported its validity and reliability
Landers et al (2014)20	√	√	√	√	√	√	√	Depicted the SMT-based study model to operationalize study concepts
Brown et al (201l)25	√	√	√	√	√	√	×
Merriman et al (201l)24	√	√	√	√	√	√	√
Miaskowski et al (2011)22	√	√	√	√	√	√	×
Miaskowski et al (201l)23	√	√	√	√	√	√	×
Dodd et al (2010)26	√	√	√	√	√	√	×
Utne et al (2010)28	√	√	√	√	√	√	×
Van Onselen et al (2010)27	√	√	√	√	√	√	×
Ruegg et al (2009)29	√	√	√	√	√	√	×
Fall-Dickson et al (2008)34	√	√	√	√	√	√	√	Depicted the SMT-based study model to operationalize study concepts
Suwisith et al (2008)30	√	√	√	√	√	√	×
Lee et al (2008)33	√	√	√	√	√	√	×
Chou et al (2007)35	√	√	√	√	√	√	×	Depicted the SMT-based study model to operationalize study concepts
Ahlberg et al (2005)37	√	√	√	√	√	√	√

Abbreviation: SMT, Symptom Management Theory.

^aCheck marks indicate fulfillment and cross sign “x” indicate nonfulfillment of criteria; blank cells indicate the use of SMT only as the theoretical framework.

^bCriteria 1: One of the study purposes is to determine underlying validity of model’s assumptions or propositions.

^cCriteria 2: Study explicitly states the model as framework for research.

^dCriteria 3: Model is discussed in sufficient breadth and depth, making the relationship between model and study hypotheses or purposes clear.

^eCriteria 4: Study hypotheses or purposes deduced clearly from model’s assumptions or propositions.

^fCriteria 5: Study hypotheses or purposes are empirically tested in appropriate manner.

^gCriteria 6: As a result of empirical testing, indirect evidence exists of validity (or lack thereof) of model’s assumptions or propositions.

^hCriteria 7: Evidence is discussed in terms of how it supports, refutes, or explains relevant aspects of the model.

Table 3.

Extent of Testing of SMT Through Verification of Personal Experiences¹⁶ Among Adults With Cancer^a (N = 1)

Author (Year)	Criteria 1b	Criteria 2c	Criteria 3d	Criteria 4e	Criteria 5f	Criteria 6g	Criteria 7h	Criteria 8i	Criteria 9j	Criteria 10k
Landers et al (2012)21	√	√	√	√	√	×	Not applicable	√	√	Not applicable

Abbreviation: SMT, Symptom Management Theory.

^aCheck marks indicate fulfillment and cross sign “x” indicate nonfulfillment of criteria.

^bCriteria 1: A purpose of the study is to verify the relationship of the described personal experiences to the specific philosophical beliefs and assumptions of the nursing theory.

^cCriteria 2: Identification of the research question is based on an attempt to provide elaboration of concepts related to the nursing theory.

^dCriteria 3: Primary data sources include sufficient in-depth descriptions of personal experiences to capture the essence of the phenomenon under investigation.

^eCriteria 4: Simplicity, ethical integrity, and aesthetic presentation are integral characteristics of the described personal experiences.

^fCriteria 5: Analysis of data incorporates a sense of wholeness of the described personal experiences.

^gCriteria 6: Formative hypotheses and/or theory are derived inductively from qualitative analysis of the described experiences.

^hCriteria 7: Multiple personal experiences of an individual and/or similar personal experiences of several individuals about a particular phenomenon are used to validate the derived hypotheses.

ⁱCriteria 8: Analytical procedures of data analysis and fit of the generated concepts to the personal experiences provide indirect evidence of the validity (or lack thereof) of the nursing theory.

^jCriteria 9: Findings are discussed in terms of how they relate to the nursing theory.

^kCriteria 10: If an existing nursing theory is used to frame a theory that is to be developed and tested inductively, both the deve1oping and existing theories must be internally consistent and congruent with one another.

Table 2.

Extent of Testing of SMT Through Application in Nursing Practice¹⁶ Among Adults With Cancer^a (N = 3^b)

Author (Year)	Criteria 1c	Criteria 2d	Criteria 3e	Criteria 4f	Criteria 5g	Criteria 6h	Criteria 7i	Use of SMT in Nursing Practice
Skrutkowski et al (2008)31	√	√	√	√	√	√	×	Developed a specialized nursing role (pivot nurse in oncology) and tested its impact on patient outcomes
Moore et al (2008)32,b Johnson et al (2007)36,b	√	√	√	√	√	×	×	Developed a multifaceted quality improvement and education program (AIM Higher Initiative) to improve symptom assessment, management, and information distribution
Zibecchi et al (2003)38,b Ganz et al (2000)39,b	√	√	√	√	√	√	√	Developed a structured program (Comprehensive Menopausal Assessment) based on SMT dimensions and tested clinical protocols for symptom management

Abbreviation: SMT, Symptom Management Theory.

^aCheck marks indicate fulfillment and cross sign “x” indicate nonfulfillment of criteria.

^bArticles related to the same study.

^cCriteria 1: A purpose is to demonstrate the problem-solving effectiveness of the theory for nursing practice.

^dCriteria 2: Study explicitly states the model as framework for application process.

^eCriteria 3: The plan for implementation identifies specific problems targeted for solution through application of the nursing theory.

^fCriteria 4: The problems to be addressed represent interesting, important, and ethical problems for nursing practice.

^gCriteria 5: Outcomes are measured in terms of problem-solving effectiveness of the applied nursing theory.

^hCriteria 6: Problem-solving effectiveness is determined in comparison with applications in which the nursing theory is not used.

ⁱCriteria 7: Findings are discussed in terms of how the nursing theory was instrumental in defining and implementing problem-solving strategies.

Feasibility of implementation

Feasibility of implementing practical activities based on the theory is an important requisite for pragmatic adequacy.¹⁴ Our review findings suggest that the human and material resources needed to implement SMT-based activities are reasonable if time and required finances are invested in protocol-testing procedures and in-service education of nurses. For instance, an application of SMT for protocol development³⁹ required 6 months of training for a family nurse practitioner to provide the study intervention. The authors, however, note that nurse practitioners in other fields with their existing assessment and counseling skills could also provide the intervention with additional training in the areas of menopause and/or breast cancer.³⁹

Legal ability of practitioners for implementation

There are no legal barriers to implementing SMT-based nursing activities as long as nurses have valid professional licensure and the activities are within their functional scope. However, collaboration between the health care institution and other health professionals is required to bring about meaningful SMT-based changes in clinical practice.

Compatibility with public and health care system expectations

For pragmatic adequacy, it is important that theory-based activities are compatible with expectations held by the health care system and the public.¹⁴ SMT offers a comprehensive framework for symptom management for individuals with varied health problems. Health care systems strive to alleviate suffering of patients, and nurses specifically are expected to treat or assuage negative symptoms. In this context, SMT-based practical activities would undeniably meet existing expectations.

Favorable outcomes

Theory-based practical activities are socially meaningful when they lead to favorable outcomes.¹⁴ On the basis of our review findings, SMT has been applied to yield favorable patient outcomes such as quality of life, functional status, and sexual function. SMT-based activities have also been shown to reduce negative symptom experiences and improve management of symptoms, which subsequently improve patient satisfaction.

Problem-solving effectiveness

Finally, the outcomes of theory-based practical activities are judged by problem-solving effectiveness.¹⁴ This criterion requires a comparison of outcomes of use of the theory and outcomes in the same situation when the theory is not used.¹⁴ In this review, only 2 studies compared the outcomes of an SMT-based intervention with outcomes of usual care (Table 2). One study³⁹ reported significant improvement in menopausal symptoms and sexual function in the treatment group (comprehensive menopausal assessment intervention). The other study³¹ did not find any significant differences between the intervention group (pivot nurse in oncology) and the usual care group in symptom distress, fatigue, quality of life, or health care usage. Additional research is required to obtain robust comparisons between cancer-related clinical outcomes with and without use of SMT. Adoption of SMT-based intervention protocols or assessment tools that are empirically tested against a control would strengthen the theory’s usefulness in problem solving among adults with cancer.

EXTENT OF USE OF SMT AMONG ADULTS WITH CANCER

Although the focus of our review was cancer-related studies that mention SMT as theoretical framework, we were also interested to examine the extent¹⁵ to which the studies had used the theory. For this purpose, we examined the studies in our review against Silva’s¹⁵ evaluation criteria for empirical testing of a theory. The studies with qualitative perspectives and application to nursing practice were examined using the alternative approaches to theory testing proposed by Silva and Sorrell.¹⁶ Tables 1–3 describe the criteria and extent of use^15,16 of SMT by the studies in this review.

All the studies explicitly identified SMT as a framework for their research and operationalized SMT concepts and propositions in their respective studies. Although these 20 studies aimed to support or refute the validity of SMT concepts or propositions, only 8 studies discussed the study findings in terms of how they support, refute, or explain relevant aspects of the model (Tables 1–3). Since Silva¹⁵ proposes that the extent of use of a theory is considered “adequate” only when all evaluation criteria are fulfilled, only 35% of the studies in this review used SMT to an adequate extent (see Tables 1–3). Integrating SMT in study results and discussions and describing how the study findings support or refute SMT would add to the utility and validity of the theory in real-world research and practice. For instance, Fall-Dickson et al³⁴ reported how their study findings demonstrated the utility and validity of SMT in guiding examination of perception, evaluation, and response components of the oral pain experience. Landers et al²⁰ discussed how testing the relationships between the dimensions of SMT and their components was an important feature of their study. Another study’s authors discussed qualitative perspectives on bowel symptom experiences and management strategies using the concepts of SMT.²¹ It can be argued that such explicit mention of a theory in discussion sections, or interpreting study findings against the background of said theory, is not required, given constraints in article length or risk of redundancy, especially for seasoned researchers. In reality, however, such practices would not only serve as good examples for novice researchers attempting to apply theory in research or practice but also explicitly contribute to a theory base. Studies that only identify a theory as the conceptual framework and do not circle back to clearly report how their findings support or refute the applied theory might still contribute to the theory base; however, such conclusions are dependent on readers’ research and analytical expertise.

IMPLICATIONS FOR NURSING IN ADULTS WITH CANCER

Our review findings support the applicability of SMT in real-world oncology settings. Given the complexity of cancer care, SMT’s interrelated symptom management dimensions and the various components of symptom management strategies are undoubtedly crucial and relevant to planning symptom management interventions for adults during their cancer trajectory. The symptom outcomes described in SMT are also significantly relevant to adults with cancer.

However, certain SMT limitations have specific implications for adults with cancer. Two of these implications have been reported among the pediatric oncology population as well¹²: the inclusion of family perspectives in symptom outcomes, and the potential inability to self-report symptoms among adults due to head and neck cancer or advanced cancer states. In SMT, the dimensions of symptom experience and symptom management strategies involve caregivers’ perspectives to an extent, yet the symptom outcome dimension is focused primarily on the person experiencing the symptom (except perhaps for health care costs, which may be incurred to the family). Cancer caregiving burden is known to vary across the cancer trajectory and has been linked with subsequent health impairment among caregivers,^41,42 and SMT might have limitations in examining cancer-related psychological symptoms in patient-caregiver dyads.

The authors of SMT assert that caregivers’ interpretation of patient symptoms can be assumed accurate for nonverbal patients,⁷ but in cancer, this assumption presents multiple issues. Caregivers have typically been found to overestimate symptom burden of patients with cancer,^43,44 and caregiver accuracy at interpreting symptom severity does not improve over time.⁴³ In addition, certain characteristics influence accurate reporting, such as level of patient disability, gender and health status of the caregiver, living arrangements of the caregiver, and assistance provided by the caregiver in activities of daily living and medical care.⁴⁵ Few other limitations of SMT that have implications for the population of adults with cancer are described later.

Distinction between symptom perception and symptom response

A certain ambiguity exists when differentiating between perception of a symptom and responses to it. For instance, Utne et al²⁸ examined relationships between symptoms such as mood disturbances (anxiety and depression) and pain in adults hospitalized with cancer. The authors of SMT describe mood changes as psychological responses to a symptom. They do not give clear direction when to consider such experiences as a psychological symptom versus a psychological response to another symptom. A similar ambiguity was reflected in a study that examined sleep disturbances and pain in individuals with breast and prostate cancer.²⁴ Fragmented sleep is described by the SMT authors as a physiological response to pain. It is again unclear when a particular physiological or psychological response to a symptom such as pain can be considered a new symptom in itself.

Temporal components of the symptom experience

SMT includes time only in regard to “when” an intervention is delivered. Time-based changes in symptom experiences, symptom management strategies, and symptom outcomes are not specified. This limitation, mentioned by other nurse researchers^9,12 and acknowledged by SMT authors,⁸ has specific implications for adults with cancer, who have varying symptom experiences over time depending on their disease stage and treatment phase. Five studies in this review reported changes in cancer-related symptoms over time.^{22,23,29,37,39} Although these findings provide some insight into potential future versions of SMT, more SMT-based longitudinal studies among adults with cancer are required to identify potential issues in theory application related to examining symptoms in relationship to time.

Relationships among co-occurring symptoms

Symptom presentation in individuals with cancer is often complex, with symptoms occurring in clusters. Although the original SMT focused on how a single symptom can be studied, the authors maintain that the concept of symptom cluster is consistent with SMT.⁸ Barsevick⁴⁶ was among the first to identify the limitations of SMT in symptom clusters. However, this review noted that studies by the original SMT authors used SMT to assess symptom clusters or relationships among co-occurring symptoms in adults with cancer.^22–28,30 For instance, Merriman et al²⁴ reported significant correlation between attentional fatigue and other symptoms such as anxiety, depression, and sleep disturbance (Supplemental Digital Content Table 1 available at: http://links.lww.com/ANS/A28). Significant relationships were also demonstrated between mood disturbance and pain²⁸ and between sleep disturbance and anxiety, depression, and fatigue.^22,23 Although SMT in its current form does not address these issues, our review findings point to a research trajectory for use of SMT in cancer, where such empirical evidence will contribute to further revision of SMT. On the contrary, it may be challenging for a middle-range theory such as SMT to address all the complex relationships between and among symptoms within a cluster for all cancer types.⁴⁶ In oncology patients, symptoms vary with cancer types^24,26 and cancer stage.¹⁹ Even within a specific cancer diagnosis, the symptom clusters could change over the course of treatment.²² In addition, one symptom could exacerbate another symptom⁴⁶ and an intervention strategy aimed at relief of one symptom may lead to worsening of another symptom or development of a new symptom. For instance, using opioids for cancer pain may lead to new symptoms such as nausea, constipation, or pruritus.⁴⁷

Relationships among variables of nursing domains

In SMT, the nursing domains are depicted as overlapping ovals signifying the context in which symptom management occurs. However, the relationships among various variables within and across the nursing domains are not explicitly depicted in SMT. In adults with cancer, significant relationships have been demonstrated between 2 variables of the person domain²⁷ and among variables of the person and health/illness domains.²⁹ Also, a variable for “social” or “sociological” is included in both the person and environment domains and the difference between the two is unclear. For instance, in a study of patients with lung or breast cancer,³¹ adequacy of help at home was considered a social variable and could be addressed under either the person or environment domain.

Processes of information, education, and communication

Finally, adults with cancer are engaged in dynamic processes of information, education, and communication with heath care providers, which are influenced by various factors. SMT does not address these processes and influencing factors in their entirety. To address this limitation, Johnson et al³⁶ extended the SMT goals to include information distribution. Although the SMT authors mention the importance of patient-provider communication,⁸ the model depicts adherence as the only link between symptom management strategies and outcomes. As SMT undergoes further refinement, attention to these limitations could enhance its utility among adults with cancer.

CONCLUSION

The analysis and evaluation of SMT in the context of research and clinical practice involving adults with cancer indicate that SMT comprehensively weaves together various aspects of symptom management and provides a systematic context for improving symptom management. Additional research focusing on problem-solving effectiveness using SMT will maximize the theory’s utility for achieving clinically relevant outcomes. Overall, SMT provides useful guidance for clinical practice and research among adults with cancer and certain modifications could enhance the theory’s utility in this population. The utility of a newly modified SMT would then need to be established through further research utilizing longitudinal designs to address concurrent symptoms.

Statements of Significance.

What is known or assumed to be true about this topic?

• Theories of symptom management help nurse researchers organize conceptual relationships within the symptom experience.

• SMT, originally Symptom Management Model, was developed in 1994 by the Symptom Management Faculty Group at the University of California, San Francisco School of Nursing. The model was revised in 2001 and 2008.

• The theory has been used in various patient populations, but no formal critique of SMT with implications for adults with cancer has been done. In addition, no analysis of SMT with respect to its extent or degree of use has been done. Thus, there is a need for a systematic appraisal of SMT and extent of its use to understand its utility for research and practice involving adults with cancer.

What this article adds:

• We evaluated 20 SMT-guided studies among adults with cancer, published between 2000 and 2018.

• Per Fawcett and DeSanto-Madeyaʼs¹⁴ 2013 framework for theory analysis and evaluation, SMT demonstrates good social and theoretical significance, internal consistency, testability, and pragmatic adequacy. Empirical adequacy of SMT is demonstrated in 80% of the studies. However, the theoryʼs reduced parsimony would require researchers to understand the theory’s concepts and propositions in detail to ensure appropriate application. Some theoretical propositions were less examined and supported than others; symptom experience dimension was most researched in adults with cancer. Only 2 studies compared cancer-related clinical outcomes with and without use of SMT, thus limiting conclusions regarding SMT’s problem-solving effectiveness in cancer

• Per Silva’s criteria for examining extent of a theory’s use, SMT was used to an adequate extent only in 35% of the studies.

• The article identifies certain limitations of SMT that have implications for adults with cancer.