Primary brain tumor representation in the post-traumatic growth literature: A scoping review

Abstract

Background

Post-traumatic growth (PTG) has been extensively explored within general oncology, yet little is known about the experience of PTG in neuro-oncology. This study aimed to determine the representation of patients with primary brain tumors (PBT) in the PTG literature.

Methods

PsycINFO, PubMed, and CINAHL were systematically searched from inception to December 2022. Search terms were related to personal growth and positive reactions to cancer. Articles were first screened by titles and abstracts, then full texts were reviewed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses method.

Results

A total of 382 articles met the inclusion criteria. Of those, 13 included patients with PBT. Over 100 000 cancer patients were represented, with 0.79% having a PBT. Most research focused on low-grade gliomas. PTG negatively correlated with post-traumatic stress symptoms and avoidant coping. In the sole longitudinal study, patients with PBT demonstrated improved PTG after 1 year. Three quasi-experimental studies investigated the effect of mindfulness-based interventions with mixed-cancer samples and demonstrated improvement in PTG.

Conclusions

The inclusion rate of patients with PBT in the PTG literature was significantly lower than the population prevalence rate (1.3% of cancer diagnoses). Relatively few studies focused exclusively on how patients with PBT experience PTG (k = 5), and those that did only included low-grade glioma. The experience of PTG in those with high-grade glioma remains unknown. Patients with PBT are scarcely included in research on PTG interventions. Few studies examined the relationship between PTG and medical, cognitive, or psychological characteristics. Our understanding of the PTG experience in neuro-oncology remains extremely limited.

For most individuals facing cancer, the shock of the initial diagnosis represents an acute trauma. Thereafter, the cancer experience consists of a continual process of potentially traumatic events which can include surgical procedures, inpatient hospital stays, adverse effects from treatments, scan anxiety, progression of disease, physical and functional decline, and changes in social roles throughout the disease course. With medical advancements extending life, the cancer experience is also now prolonged, placing patients at risk for lengthened psychological distress.¹ While psychological distress is a negative consequence of cancer-related trauma, it also creates the potential for positive, transformative growth. Such growth, often termed “post-traumatic growth (PTG),” is the experience of positive psychological changes—such as increases in resilience and positive coping—following a traumatic life experience.² Importantly, PTG is not the absence of psychological distress; rather, PTG refers to affective and cognitive growth beyond one’s pre-trauma baseline.^2,3

When a major trauma disrupts one’s beliefs about the controllability, predictability, and benevolence of the world, the individual is faced with forming a new existential schema to help derive meaning and benefit from their experience.² A cancer diagnosis and related treatments have the potential to alter one’s beliefs and thus provide an opportunity to foster PTG. A recent review found that cancer survivors report higher levels of PTG when compared to individuals who experienced accidental injury.⁴ Patients with cancer also report heightened domains of PTG including personal strength and spiritual development.⁵ Moreover, PTG has the potential to mediate the relationship between psychosocial stressors (eg, post-traumatic stress, depression, socioeconomic vulnerability) and quality of life in patients with cancer, such that higher PTG may buffer the relationship between distress and health-related quality of life.^4,6

A cancer population that has been historically underrepresented in the existential distress literature is neuro-oncology.⁷ Patients with primary brain tumors (PBT) experience unique cognitive and emotional consequences as a result of their tumor and the subsequent aggressive treatments, often facing a poor prognosis with rapid disease progression and declining functioning.⁸ Although medical advancements have briefly prolonged death for patients with PBT, these treatments remain noncurative. Therefore, it is understandable that patients with PBT endorse greater psychological distress compared to other oncology populations.^7,9,10 As mentioned previously, a common theory explaining PTG necessitates that for PTG to occur, some level of distress and emotional pain is required.² Because psychological distress is ubiquitous in neuro-oncology, it is likely that PTG would be a relevant construct to both assess and promote which may improve the emotional and interpersonal lives of those living with a brain tumor.

A greater understanding of PTG in neuro-oncology may play a vital role in informing treatment, aiding in the reduction of psychological or existential distress, and supporting palliative end-of-life care for this advanced cancer population. As seen in the review of PTG in other cancer groups,^3,11–13 having a terminal disease does not preclude positive growth experiences, and therefore patients with PBT may experience specific aspects of growth which could inform the development of interventions. Therefore, the primary objectives of this scoping review were to (i) determine the representation of patients with PBT in the current PTG literature, (ii) provide a summary of the key findings related to PTG in neuro-oncology, and (iii) discuss suggestions for future research on PTG in those challenged by brain cancer.

Methods

Search Procedure and Review Parameters

A literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)¹⁴ to identify the representation of patients with PBT in the PTG literature. Ethical approval was not required. Studies were identified through keyword searches relevant to the fields of psychology, nursing, and oncology. Three databases were systematically searched: PsycINFO, PubMed, and CINAHL. Search terms included (post-traumatic OR post-traumatic OR post traumatic OR stress-related OR stress related OR personal OR adversarial OR existential) AND (growth) AND (cancer OR oncology OR tumor OR neoplasm). In addition, reference lists from relevant texts (eg, review papers) were checked to identify additional articles. Articles were collected from inception through December 2022.

Article titles and abstracts were reviewed using Rayyan Systematic Review Software,¹⁵ which allowed for a double-blind review by 7 reviewers (J.K.B., F.J.A., A.R.L., A.L., M.P.R., K.D.W., and S.E.B.) to evaluate manuscript inclusion. If the abstract was ambiguous, articles were retrieved, and the full text was reviewed. The review was restricted to texts that met the following inclusion criteria: (a) use of a quantitative measure of PTG, (b) adult samples (aged 18+), and (c) a provided breakdown of specific cancer diagnoses if the sample was mixed. There was no restriction regarding publication year. PTG measures were defined by review of the literature to identify which measures have acceptable construct validity to assess PTG.¹⁶ Publications were excluded if they: (a) did not investigate patients with cancer, (b) were in a foreign language and translation was not available, or (c) were a dissertation, poster abstract, or other research articles not published in a peer-reviewed journal.

Data Extraction

For articles that met inclusion criteria, reviewers collected both the name of the PTG measure and the breakdown of cancer types represented in the overall sample.¹⁷ The independent reviewers recorded queries and issues during the data extraction process for exclusion criteria. When a query was recorded, reviewers A.R.L. and S.E.B. collaboratively reviewed the publications to resolve discrepancies. Queries related to coding exclusion criteria were present in 14.16% of the articles.

For the studies that explicitly reported on patients with PBT, a more thorough data extraction was undertaken. Study design, PTG measure characteristics, and the following domains of relevant results were tracked: (i) prevalence of PTG, (ii) demographic correlates of PTG, (iii) psychological and health-related correlates of PTG, and (iv) psychosocial interventions utilized to improve PTG.

Results

Our initial search yielded 7 748 articles (PubMed = 5652; PsycINFO = 1038; CINAHL = 1058). Following the removal of duplicate records and initial screening of the titles and abstracts, 520 articles were eligible for full-text review. Of these, 382 met the above inclusion criteria. Thirteen articles included patients with PBT and were more thoroughly reviewed.^18–30 See Figure 1 for the full PRISMA flow diagram and Table 1 for an overview of the 13 included studies.

Figure 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram illustrating the study selection process. Abbreviation: PBT, primary brain tumor; PTG, post-traumatic growth.

Table 1.

PTG Literature Included Patients with PBT

Study Citation	Study Design	Overall Sample	PBT Sample	Domains Assessed	Measure Used	Findings	PBT-Specific Results
Campanella et al. (2017)18	Cross-sectional	N = 50 Italian (no further race/ethnicity reported) Age, M = 40.02, range = 19–69 54% female Years since resection M = 3.35	N = 50 (100% of sample) All low-grade glioma 50% left hemisphere	Personal growth, positive relations, purpose in life	Psychological Well-Being Scale	Patients did not differ from reference population or from their relatives’ collateral ratings. Most patients indicated a positive change in life outlook/perspective after their illness (42%), whereas changes were negative for only 16%	Tumor characteristics and cognitive status were not correlated with PTG
Campo et al. (2017)19	Quasi-experimental	N = 25 80% White, 8% Asian, 12% Other race Age, M = 26.9, range = 18–29 100% female Years since dx M = 3.2	n = 1 (3% of sample)	Relating to others, new possibilities, personal strength, spiritual change, appreciation of life	Post-traumatic Growth Inventory	After mindful self-compassion intervention, significant increase in overall PTGI score, domains: relating to others, new possibilities	Sample size did not allow for analysis based on type of cancer
Faghani et al. (2022)20	Quasi-experimental	N = 30 Italian (no further race/ethnicity reported) Age and 60% female Max of 1 year since last cancer treatment	n = 1, in the supportive psychotherapy group (3.3% of sample)	Only used total PTG score	Post-traumatic Growth Inventory—Italian	PTG increased after mindfulness based supportive psychotherapy compared to treatment as usual. The increase in PTG was sustained when reassessed at a 3-month follow-up	Sample size did not allow for analysis based on type of cancer
Garland et al. (2007)21	Quasi-experimental	N = 104 race/ethnicity, age, gender, and years since dx were separated by intervention group, see article	n = 2 (3.3% of mindful-based intervention sample)	Relating to others, new possibilities, personal strength, spiritual change, appreciation of life	Post-traumatic Growth Inventory - Revised	Over time, significant increase in overall PTGI score and domains: relating to others, new possibilities, personal strength	Sample size did not allow for analysis based on type of cancer
Gori et al. (2021)22	Cross-sectional	N = 154 Italian (no further race/ethnicity reported) Age, M = 51.35, range = 18–79 90.3% female Years since dx not reported	n = 4 (2.6% of sample)	Relating to others, new possibilities, personal strength, spiritual change, appreciation of life	Post-traumatic Growth Inventory—Italian	Positive attitudes mediated the relationship between resilience and PTG	Sample size did not allow for analysis based on type of cancer
Ho et al. (2004)23	Measurement validation	N = 188 Chinese (no further race/ethnicity reported) Age, M = 49.29, range = 26–69 82.98% female Years since dx: > 5 years	n = 1 (0.5% of sample)	Self, spiritual, life orientation, interpersonal dimension, intrapersonal dimension	Post-traumatic Growth Inventory—Chinese	EPA and CFA provided 4-factor solution for Chinese version of PTGI: self, spiritual, life orientation, interpersonal	Sample size did not allow for analysis based on type of cancer
Jaarsma et al. (2006)24	Cross-sectional	N = 294 Dutch (no further race/ethnicity reported) Age, M = 55.56, range = 21–84 72.1% female Years since dx M = 3.9	n = 5 (6.25% of sample)	Relating to others, new possibilities, personal strength, spiritual change, appreciation of life and total PTG score	Post-traumatic Growth Inventory—Dutch	PTG was negatively correlated with age; PTG positively correlated with innerness, openness personality trait, and intrusion/stress. Women reported more PTG than men, and more growth in relating to others, new possibilities, and personal strength	Sample size did not allow for analysis based on type of cancer
J. Kim & Shin (2021)25	Cross-sectional	N = 114 Korean (no further race/ethnicity reported) Age, M = 55.46, range not reported 36% female Years since dx reported categorically	N = 114 • Malignant, n = 71 (62.3% of sample) • Benign, n = 43	Relating to others, new possibilities, personal strength, spiritual change, appreciation of life	Post-traumatic Growth Inventory	Overall PTG, self-perception, and relation to others were correlated with coping with cancer and receiving support from healthcare professionals	PTG was higher for patients with malignant tumors than in patients with benign tumors
S. R. Kim et al. (2020)26	Cross-sectional	N = 120 Korean (no further race/ethnicity reported) Age, M = 55.3 49.2% female Months since dx M = 26.5	N = 120 (100% of sample) 10.8% grade I, 26.7% grade II, 16.7% grade III, 45.8% grade IV	Only used total PTG score	Post-traumatic Growth Inventory—Korean	PTG was not correlated with quality of life or severity of symptoms or symptoms interfering with life; resilience and PTG were positively correlated	The relationship between PTG and tumor characteristics was not statistically analyzed
Li et al. (2019)27	Cross-sectional	N = 330 Chinese (no further race/ethnicity reported) Age, M = 40.2, range = 18–67 43% female Participated ~1 month after surgery	N = 330 (100% of sample) • All low-grade glioma • 45.5% left hemisphere 2.4% bilateral	Only used total PTG score	Post-traumatic Growth Inventory—Chinese	PTG positively influenced quality of life; however, post-traumatic stress symptoms negatively impacted this relationship. Avoidant coping also inhibited the relationship between PTG and quality of life	The relationship between PTG and tumor characteristics was not statistical analyzed
Mostarac and Brajković (2022)28	Cross-sectional	N = 149 Croatian (no further race/ethnicity reported) Age, M = 49.18, range = 21–85 70.5% female Years since treatment, M = 5.89, SD = 6.67	n = 2 (0.01% of sample)	Relating to others, new possibilities, personal strength, spiritual change, appreciation of life	Post-traumatic Growth Inventory—Croatian	Mediation analyses showed that PTG had both a positive direct and indirect relationship on life satisfaction when individuals reported higher presence of meaning in their life	Sample size did not allow for analysis based on type of cancer
Rider Mundey et al. (2019)29	Cross-sectional	N = 221 74.7% female 91.9% White, 2.3% Latinx, 2.3% Other, 1.4% American Indian, 0.9% Asian, 0.9% Black Age was not reported Years since dx was reported categorically	n = 2 (0.8% of sample)	Only used total PTG score	Post-traumatic Growth Inventory	Deliberate rumination and emotional intelligence positive influenced PTG	Sample size did not allow for analysis based on type of cancer
Wang et al. (2018)30	Longitudinal	N = 260 Chinese (no further race/ethnicity reported) Age, M = 42, range = 18–67 44.2% female T1 ~1 month after surgery; T2 ~1 year after surgery	N = 260 (100% of sample) • All low-grade glioma • 45.8% left hemisphere 1.5% bilateral	Relating to others, new possibilities, personal strength, spiritual change, appreciation of life	Post-traumatic Growth Inventory—Chinese	All domains of PTG, except new possibilities, increased after 1 year. Hierarchical linear model showed patients with higher levels of PTG had better quality of life; PTG also significantly moderated the effect of depression on quality of life	The relationship between PTG, tumor characteristics and cognitive status was not analyzed

Abbreviations: dx, diagnosis; PBT, primary brain tumors; PTG, post-traumatic growth; PTGI, Post-traumatic Growth Inventory; T1, first time point; T2, second time point; EFA, exploratory factor analysis; CFA, confirmatory factor analysis.

General Oncology Population

A total of 109 877 participants were represented across the 382 articles. PTG was most often assessed in cancer in female sex organs (eg, breast, ovarian; 49.9%), followed by cancer in the digestive system (17%), male sex organs (ie, testes and prostate; 12.9%), respiratory system (7.1%), and blood and lymphatic system (7.1%). Unique or less common cancer sites represented were bone, carcinoid, soft tissue, thyroid (3.1%) and skin and melanomas, urinary system, and unspecified types of cancer (<1.5%). The 382 studies varied widely in their methodological approach. The most frequently used measure, at 84.7%, was the Post-Traumatic Growth Inventory² (PTGI) followed by the Benefit Finding Scale³¹ (6.7%), Silver Lining Questionnaire³² (2.1%), Stress-Related Growth Scale³³ (2.1%), and Perceived Benefits Scale³⁴ (1.2%).

Representation of Patients with PBT

Of the 109 877 cancer patients represented in the included studies, 0.79% had a diagnosis of PBT (n = 871). Of the 382 articles that met inclusion criteria, 13 included patients with PBT. Of note, the majority of studies (76.9%) were conducted and published within the past decade. Within these 13 studies, patients with PBT represented 43.7% of participants (892 out of 2039; ranging 0.5%–100%). It should be noted that more than half of the articles were mixed-cancer samples that included 8 or fewer patients with PBT.^{19–24,28,29} When studies did examine patients with PBT specifically (k = 5), the majority focused exclusively on low-grade glioma (k = 3; n = 662). One included both benign and malignant tumors (n = 71; 62.3% of the overall sample) but did not report a specific type or grade of PBT.²⁵ Only 1 study²⁶ included patients with a range of low- to high-grade gliomas (see Table 1 for percentages of low and high grade). None of the studies with a mixed-diagnosis sample performed comparative analyses between cancer diagnoses to investigate within- or between-group differences in PTG.

Methods Used to Assess PTG in Patients with PBT

Nearly all studies that included patients with PBT used a version of the PTGI (ie, original version or translations; k = 12). The 5 psychometrically validated PTGI subdomains are: (i) a greater appreciation for life and a changed sense of priorities, (ii) more intimate interpersonal relationships, (iii) increased personal strength, (iv) recognition of new possibilities and/or life paths, and (v) increased spiritual development.² Occasionally, studies that use translated versions revealed alternative domains (eg, “interpersonal and intrapersonal dimensions” in a Chinese translation²³ and “changes in self-person” in a Korean translation).²⁵ Campanella and colleagues¹⁸ used select subscales from the Psychological Well-Being Scale as an alternative measure of PTG. Secondly, nearly all studies that included patients with PBT employed a cross-sectional approach, with only 1 study collecting longitudinal data to assess how PTG changed over time after tumor resection.³⁰ Three studies implemented clinical interventions and investigated PTG as an outcome variable.^19–21

PTG Results from Studies Including Patients with PBT

For studies using the PTGI (k = 12), means and standard deviations of the total scores and subdomains are summarized in Table 2. A PTGI total score of ≥46 indicates moderate-to-high overall PTG and a subscale score of >3 indicates high growth in that specific domain.^35–37 For overall PTG, all studies reported moderate-to-high growth. Similarly, all but 1 study reported high PTG across all subdomains; participants in Jaarsma and colleagues’ study²⁴ reported low spiritual growth following their cancer diagnosis. Lastly, only 1 study reported and analyzed the relationship between tumor characteristics, cognitive functioning, and PTG; none were correlated with PTG.¹⁸

Table 2.

Level of PTG in Studies That Included Patients with PBT

			PTGI Scores M (SD)
Study Information		Sample Size (N)	New Possibilities	Relating to Others	Personal Strength	Spiritual Change	Appreciation of Life	Total Score
Campo et al. (2017)19 Mindfulness self- compassion	Pre	25	11.76 (4.7)	15.05 (7.2)	11.23 (5.2)	3.33 (3.6)	9.81 (3.2)	49.8 (19.8)
	Post		14.28 (5.3)	19.48 (6.8)	13.00 (4.8)	3.90 (3.4)	10.24 (2.9)	60.23 (19.3)
Faghani et al. (2022)20 Supportive psychotherapy	Pre	15	—	—	—	—	—	63.87 (11.03)
	Post	15	—	—	—	—	—	73.00 (12.83)
	F/U	15	—	—	—	—	—	73.13 (12.76)
Faghani et al. (2022)20 Treatment as usual	Pre	15	—	—	—	—	—	61.15 (10.41)
	Post	15	—	—	—	—	—	62.05 (10.27)
	F/U	15	—	—	—	—	—	61.24 (10.34)
Garland et al. (2007)21 Healing arts program	Pre	104	14.78 (5.68)	22.95 (8.31)	11.85 (5.27)	4.92 (3.24)	11.73 (3.32)	66.24 (21.24)
	Post		14.86 (6.75)	24.32 (7.81)	12.27 (5.08)	5.02 (3.15)	11.16 (3.40)	68.09 (22.22)
Garland et al. (2007)21 Mindfulness-based stress reduction	Pre	104	12.25 (5.27)	22.72 (7.80)	10.40 (4.52)	4.95 (3.35)	10.17 (3.48)	60.48 (19.51)
	Post		14.23 (6.79)	24.07 (7.52)	11.48 (4.53)	5.04 (3.30)	11.07 (2.62)	65.89 (18.90)
Gori et al. (2021)22		154	17.39 (6.38)	23.43 (8.48)	15.12 (4.69)	4.88 (3.26)	12.08 (3.41)	72.90 (21.49)
Ho et al. (2004)23		188	17.01 (3.95)	23.34 (4.47)	13.54 (2.85)	5.92 (2.35)	10.18 (2.54)	—
Jaarsma et al. (2006)24		294	8.94 (6.95)	18.01 (8.65)	9.50 (5.60)	2.55 (2.99)	8.44 (4.42)	47.87 (24.04)
J. Kim and Shin (2021)25a		114	9.57 (1.46)	16.02 (2.32)	18.47 (2.32)	6.68 (1.07)	n/a	50.75 (5.08)
S. R. Kim et al. (2020)26		120	—	—	—	—	—	63.36 (21.44)
Li et al. (2019)27		330	—	—	—	—	—	52.63 (11.73)
Mostarac and Brajković (2022)28		149	3.21 (1.33)	3.20 (1.26)	3.67 (1.24)	2.83 (1.71)	3.71 (1.30)	62.68 (22.68)
Rider Mundey et al. (2019)29		221	—	—	—	—	—	71.90 (24.41)
Wang et al. (2018)30	Time 1	260	12.60 (4.59)	15.37 (5.81)	11.02 (3.95)	4.02 (2.75)	8.07 (3.61)	51.07 (11.26)
	Time 2		13.14 (4.36)	14.20 (13.14)	12.60 (4.21)	5.57 (2.72)	11.27 (3.30)	57.90 (11.05)

Abbreviations: F/U, follow-up; PBT, primary brain tumors; PTG, post-traumatic growth; PTGI, Post-traumatic Growth Inventory. — indicates that these studies did not report descriptive statistics for domains or total score, respectively.

^aThis study (J. Kim and Shin, 2021) used a translated version of PTGI and conducted factor analysis that revealed 4 domains rather than, no appreciation of life, and “personal strength” was replaced with “changes in self-perception.”

The majority of studies focused on exploring the psychological correlates of PTG. Kim and Shin²⁵ compared patients with malignant and benign tumors, finding PTG to be significantly higher in those with malignant tumors. They also found interpersonal coping and receiving support from healthcare professionals to be positively correlated with the PTGI total score and 2 PTGI subdomains: changes in self-perception and relation to others. Findings about the relationship between PTG and quality of life were mixed despite using similar measures, for example, Functional Assessment of Cancer Therapy. Li and colleagues²⁷ found a positive correlation between the 2, whereas S. R. Kim and colleagues²⁶ found no significant association. With regards to coping styles and their relationship with PTG, Li and colleagues²⁷ reported that post-traumatic stress symptoms and avoidant coping (eg, substance use, denial, behavioral disengagement) negatively impact the relationship between PTG and quality of life scores. In comparison, active coping (eg, emotional support, positive reframing, planning, acceptance) enhanced the positive impact that PTG had on patients’ quality of life scores.

Relatively few studies used a longitudinal design (k = 1) or implemented interventions (k = 3). In the longitudinal study,³⁰ 260 patients with low-grade gliomas were assessed and all domains of PTG, except new possibilities, significantly increased after 1 year without intervention. The interventions used to facilitate PTG were mindfulness self-compassion, mindfulness-based stress reduction (MBSR), and a program for healing through creative arts.^19,21 All 3 studies that included interventions were quasi-experimental due to a lack of randomized control trials and the incapability to assess efficacy. All 3 intervention studies were implemented in mixed-cancer samples and included only 1 or 2 patients with PBT. All interventions demonstrated significant improvements in PTG, see Table 1 for specific details. A quasi-experimental study²⁰ assessed the impact of 6 sessions of mindfulness-based supportive psychotherapy to promote PTG, resilience, and self-compassion. Results showed that patients experienced higher PTG after psychotherapy which continued until a 3-month follow-up re-assessment. Another study¹⁹ conducted a feasibility and acceptability trial of a mindful self-compassion intervention via videoconference; preliminary findings showed a positive change in total PTG score and 2 domains: relating to others and new possibilities. Feasibility was established with 84% of participants attending the majority of sessions. Participants completed the Intervention Satisfaction Scale which demonstrated high acceptability. A pilot study²¹ allowed participants to self-select into either an MBSR or a healing arts intervention. Participants in both groups showed improvements in their total PTG scores and the following domains: relating to others, new possibilities, and personal strength; however, the research design does not warrant conclusions of efficacy.

Discussion

The primary objectives of this scoping review were to (1) determine the representation of patients with PBT in the current PTG literature, (ii) provide a summary of the key findings related to PTG in neuro-oncology, and (iii) discuss suggestions for future research on PTG in neuro-oncology.

Representation of PBT

The inclusion rate of patients with PBT in the PTG oncology literature (0.79% of sample participants) was significantly lower than the population prevalence rate of PBT (1.3% of cancer diagnoses).³⁸ This review revealed that patients with PBT are underrepresented in PTG research. Exclusion of patients with PBT has been found in research on other cancer-related or existential considerations, such as fear of cancer recurrence and death anxiety, due to presumed cognitive impairment or maintaining treatment regimens through survivorship.⁷ Additionally, relatively few studies focused exclusively on neuro-oncology; rather, patients with PBT were typically included in mixed-cancer samples to a relatively small degree (n < 5). Therefore, there remains room for significant improvement in the representation of patients with PBT. First, the majority of the studies that focused on patients with PBT analyzed patients with low-grade gliomas, providing an opportunity to expand inclusion to those diagnosed with high-grade tumors. Second, because most other PBT characteristics were not measured, it is unclear if all PBT types, tumor locations, or treatment options are adequately represented in the reviewed literature. Lastly, samples of patients with PBT were often insufficiently powered for analysis, particularly those with mixed samples and studies examining PTG clinical interventions.³⁹ There remains a dearth of knowledge about applicability, effectiveness, and whether modifications are needed for interventions to accommodate the unique characteristics related to living with a brain tumor.

Summary of Key Findings

Research that assesses PTG for patients with PBT appears to be in its nascent, with most of the studies being published in the past decade. The underrepresentation of patients with PBT significantly limits our understanding of PTG in this vulnerable cancer population. Only 5 of the 13 articles investigated PTG in brain tumor-specific samples. Overall, findings revealed higher PTG among patients with malignant versus benign tumors,²⁵ a positive relationship between PTG and adaptive interpersonal coping as well as medical provider support, and mixed results regarding the relationship between PTG and quality of life.^26,27 Further, only 1 study assessed how cognitive changes due to primary brain tumors impacted anxiety, depression, and psychological well-being—including PTG—and found cognitive impairment was not associated with changes in psychological well-being or PTG subdomains.¹⁸ Interestingly, the sole longitudinal assessment of PTG found that all domains of PTG, except new possibilities, increased after 1 year without any exposure to psychological intervention.³⁰ Conclusions are limited on the impact of PTG interventions^19–21 for patients with PBT due to underrepresentation and quasi-experimental study designs. Given that there is evidence of improved PTG over time in the absence of intervention, more sophisticated clinical trials are warranted to investigate questions of efficacy. Further, the feasibility and acceptability of interventions targeting PTG have never been investigated in neuro-oncology-specific samples; thus, we know very little about the development, feasibility, and implementation of such interventions in patients with PBT. Overall, the available studies suggest that PTG is a relevant construct for patients with PBT, despite it being a cancer population that often faces life-altering outcomes and poor prognoses. Studies assessing coping style, support, and longitudinal design give support for the role of adaptive responses in promoting growth during the disease process.

Future Directions of Research on PTG in Patients with PBT

While the current studies have begun to characterize PTG for patients with PBT, significant gaps remain in the literature. First, many of the articles investigated PTG in mixed-cancer samples, obscuring the relevancy of findings to neuro-oncology patients. Moreover, of the studies that used mixed-cancer samples and included patients with PBT, half were limited in their sample sizes to allow for testing differences in PTG across diagnoses. Therefore, comparisons between patients with PBT and those with other cancer types remain largely unknown. Second, and related to the lack of brain tumor-specific studies, there needs to be validation and expansion of the demographic, medical, and psychological correlates and/or mediating factors of PTG in patients with PBT. The available studies provide a slight indication of important psychosocial characteristics to consider when studying PTG in neuro-oncology (eg, coping style). However, demographic and disease-related variables were largely overlooked in the existing research; in fact, only 1 study included participants with both low- and high-grade tumors.²⁶ The lack of high-grade tumor representation prevents exploration of how PTG may differ across diagnoses and prognoses and throughout the disease trajectory. Future research should clarify how PBT-specific variables, including tumor location, medical interventions, and neurological, cognitive, and psychological functioning impact PTG to better capture the experience of growth in this group. For example, there was some evidence in the selected studies that there is a significant negative correlation between PTG and seizures.^18,27

Relatedly, the methodology of future studies could be improved, especially in terms of measurement. Most of the identified studies used a version of the PTGI (original or translated). Some of the translated versions of the PTGI yielded different factor structures suggesting PTG may have distinctive meanings across countries, languages, or cultures. There is an existing body of literature exploring cross-cultural experiences of PTG; however, this is not frequently explored within oncology populations.⁴⁰ There is a myriad of ways of defining culture categorically and continuously; the most common in the PTG literature is comparing distal (eg, broader and indirect culture, following the general societal norms about disclosure of personal information) and proximal cultural influences (eg, narrower and more direct culture, such as direct interpersonal connections, framework from family, friends, and community).^40–42 Findings suggest that patients experience increases in PTG when the type of psychological support they receive is congruent with their sociocultural contexts of distal culture and proximal culture.^40–42 However, differences in domains and factor analyses in PTGI result in inconsistent measurement and raise challenges when making comparisons across studies. Reducing measurement inconsistency would improve ease of comparison, yet this may not be most appropriate cross-culturally or applicable across different cancer types. Further research and review are needed to explore the benefits and limitations of using the PTGI to assess patients with PBT.

Lastly, due to limited longitudinal analyses, it is unclear how PTG occurs organically over time versus through necessary psychological intervention. Indeed, PTG can occur naturally without intervention,² and thus it is important to identify individual- and system-level factors associated with this growth. Only 1 study included longitudinal assessment of PTG with patients with PBT³⁰ and found that PTG increased over time when patients endorsed higher quality of life and fewer depressive symptoms. While these findings improve our understanding of organic PTG, there remain questions regarding for whom this occurs, the timeline of occurrence, and the proper method of supporting PTG (necessity of intervention) for patients with PBT.

Early pilot studies that included patients with PBT in their interventions to improve PTG, provide a promising launching point for future clinical trials to promote PTG in neuro-oncology; for example, there is initial evidence of feasibility and acceptability of a virtual mindful self-compassion intervention in a mixed-cancer sample.¹⁹ Improved PTG factors from these 2 studies mirror Tedeschi and Calhoun’s theory² of PTG development, suggesting that fostering education, emotional regulation, disclosure, and narrative development may increase PTG. Future research should consider these findings to design trials that aim to enhance PTG in patients with PBT and make use of randomized control groups to evaluate the additive effect of intervention in light of the known natural development of PTG in other longitudinal studies.

Strengths and Limitations of the Current Review

The current review is not without limitations. Our search methods were limited to the English language, which may have precluded us from identifying all available articles or may limit the generalizability of results. Nevertheless, the countries of origin of the included articles were diverse, with many studies utilizing translated versions of the PTGI. Additionally, we did not include studies that were not peer-reviewed or qualitative in the current review. A review of qualitative studies could be especially valuable in this unique population because it may elucidate the full range of positive changes that occur following PBT diagnosis that might not be captured in quantitative assessments. Strengths of the current study include the use of a double-blinded review process per PRISMA guidelines and the use of preexisting literature to identify appropriate measures of PTG in oncology.¹⁶ This methodology decreases potential search bias and increases the internal validity of findings.

Clinical Implications

This review highlights an exploration of PTG in patients with PBT. Further, it touches upon a few psychological correlates (eg, quality of life and coping) and the potential role of clinical interventions in promoting PTG among patients with PBT. Unfortunately, there is limited understanding of the effect of demographic, disease-related, and psychological factors specific to PTG in patients with PBT.

The available literature suggests there may be natural development of PTG, and that interventions, mindfulness-based ones specifically, demonstrate feasibility/acceptability for attendance and participant satisfaction. Notably, future research is needed to establish the efficacy of these interventions for PTG and patients with PBT. There appeared to be no evidence that cognitive concerns would deter the development of PTG among patients with PBT, bolstering rationale for the inclusion of neuro-oncology patients in future PTG analyses and interventions—though more in-depth exploration is needed. These interventions could be incorporated into comprehensive neuro-oncology programs, which all too often focus on symptom management and life extension while neglecting the dire psychological needs of patients with PBT.⁴³ The positive relationship between PTG and supportive relationships with medical providers provides additional encouragement for more comprehensive neuro-oncology programs for patients with PBT. More research guided by the unique needs of patients with PBT is needed to assist clinicians in providing evidence-based treatment to promote resilience and quality of life in neuro-oncology settings.

Conclusions

Overall, PTG seems to be a relevant construct for patients with PBT, a vulnerable cancer population with unique characteristics and prognostic factors. The current review found that patients with PBT are significantly underrepresented in PTG literature, and many questions remain unaddressed. Future research should focus on clarifying the correlates, natural development, and interventions for facilitating PTG in brain tumor-specific samples. The results of future investigations may be incorporated into comprehensive neuro-oncology programming, which all too often focuses on reducing distress rather than fostering growth.

Funding

No funding was received to assist with the preparation of this manuscript.

Conflict of Interest

The authors have no competing interests to declare that are relevant to the content of this article.