Impact of Disasters on Older Adult Cancer Outcomes: A Scoping Review

Abstract

PURPOSE

There is an urgent need to address the growing global cancer burden in the context of complex disaster events, which both disrupt access to oncology care and facilitate carcinogenic exposures. Older adults (65 years and older) are a growing population with multifaceted care needs, making them especially vulnerable to disasters. The objective of this scoping review is to characterize the state of the literature concerning older adult cancer–related outcomes and oncologic care after a disaster event.

METHODS

A search was conducted in PubMed and Web of Science. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for scoping reviews, articles were extracted and screened for inclusion. Eligible articles were summarized using descriptive and thematic analyses.

RESULTS

Thirty-five studies met all criteria for full-text review. The majority focused on technological disasters (60%, n = 21), followed by climate-amplified disasters (28.6%, n = 10) and geophysical disasters (11.4%, n = 4). Thematic analysis classified the current evidence into three major categories: (1) studies concerned with carcinogenic exposure and cancer incidence related to the disaster event, (2) studies examining changes in access to cancer care and cancer treatment disruptions as a result of the disaster event, and (3) studies exploring the psychosocial experiences of patients with cancer affected by a disaster event. Few studies focused on older adults specifically, and most of the current evidence focuses on disasters in the United States or Japan.

CONCLUSION

Older adult cancer outcomes after a disaster event are understudied. Current evidence suggests that disasters worsen cancer-related outcomes among older adults by disrupting continuity of care and access to timely treatment. There is a need for prospective longitudinal studies following older adult populations postdisaster and studies focused on disasters in low- and middle-income country contexts.

INTRODUCTION

In the coming decades, public health must contend with the confluence of three major epidemiologic and societal trends: (1) a global aging population,¹ (2) a rising global cancer burden,² and (3) increased frequency and severity of complex disaster events.³ Although seemingly disparate phenomena, these three trends have the potential to interact and worsen overall population health.

CONTEXT

• Key Objective

• To characterize the state of the literature on older adult cancer–related outcomes after a disaster event.

• Knowledge Generated

• Disasters worsen cancer-related outcomes among older adults by disrupting continuity of care and access to timely treatment. There are mixed results regarding the long-term impact of disaster exposure on cancer incidence, indicating the need for longitudinal research.

• Relevance

• Results indicate the need for (1) age-stratified cancer screening programs after environmental-technological disasters; (2) emergency preparedness plans that include age-specific cancer care management guidelines; and (3) strategies to support the long-term psychosocial needs of older adult patients with cancer, particularly those displaced by disaster.

Older Adults and Cancer

The probability of developing cancer for all tumor sites doubles starting at age 60 years.⁴ The International Agency for Research on Cancer projects a worldwide 47% increase in new cancer cases between 2020 and 2040 and suggests that this trend is partially attributed to the growing aging population.² In the United States, 64% of cancer survivors are 65 years or older; by 2040, it is estimated to be 73%.⁴ Although cancer requires complex disease management among any age cohort, older adult patients with cancer face unique needs and challenges. Multiple comorbidities present before the cancer diagnosis may affect patients' functional status and ability to tolerate treatment and require complex medication management⁵; in the United States, 50% of adults over age 65 years have at least two chronic health conditions.⁶ This is compounded by social vulnerability experienced by many older adults, including high rates of isolation and lack of social support that can affect access to care and adherence to treatment regimens.⁵ These pre-existing vulnerabilities are likely to be amplified in disaster contexts, exacerbating negative oncologic outcomes among this growing population.

Older Adults and Disasters

Older adults are at disproportionate risk of experiencing ill health after a disaster.⁷ In New Orleans, 71% of the deaths attributed to Hurricane Katrina were among adults age 65 years, despite this age group comprising <15% of the population.⁶ After Hurricane Sandy, New York City experienced a significant increase in older adult emergency department utilization and admissions.⁸ The aftermath of the 2011 Great East Japan Earthquake (which precipitated a tsunami and nuclear accident at the Fukushima Daiichi Nuclear Power Plant, known as the Japan Triple Disaster⁹) highlighted older adults' vulnerability during disaster evacuation, especially among institutionalized elderly who experienced exceptionally high excess mortality in the first 3 months after the event.¹⁰ Disasters disrupt older adult social networks, compounding pre-existing isolation and leading to negative long-term consequences for access to care and disease management,⁹ psychosocial health and well-being,¹¹ and long-term resilience.¹² Exposures to harmful environmental toxins as a result of a disaster increase older adult susceptibility to opportunistic infections, disproportionately affecting those with compromised immune systems.¹³ Various studies have also suggested long-term negative health consequences for older adults experiencing multiple disasters.^11,12

Disasters and Cancer Outcomes

The term disaster refers to a suite of catastrophic events which cause systems-level disruptions and cascading consequences for human health and well-being. Disasters are the convergence of pre-existing natural hazards and socially constructed vulnerabilities.³ Disasters can also result from the disruption or breakdown of complex technological systems, which may be induced or amplified by accidents or natural hazards. Disasters disrupt health care system access and care delivery, including cancer care continuity.^14,15 Patients may be evacuated, and infrastructure damage, transportation, and communication disruptions affect care continuity.^7,16 In the acute phase of a disaster, overburdened health systems may need to triage patients, leading to treatment delays.^17,18 Treatment delays can have severe consequences on survival outcomes; delay of even a few weeks can lower survival rates for breast, colorectal, and gynecologic cancers.¹⁵

Climate-amplified (eg, hurricanes, wildfires, and other severe events beyond seasonal weather patterns), geophysical (eg, earthquakes, volcanoes), and technological disasters (eg, industrial accidents such as oil spills and nuclear meltdowns) create unique carcinogenic exposure pathways. Climate-amplified and geophysical disasters have the potential to increase exposure to carcinogens via worsened air, water, and soil quality.¹⁹ A recent scoping review of the long-term health effects of wildfires found that exposure to fine particulate matter (PM_2.5) from wildfire smoke was correlated with an increased risk of cancer of all types.²⁰ Furthermore, leukemia, breast, lung, and thyroid cancers have been shown to be associated with radiation exposure,²¹ meaning that nuclear-technological disasters are of particular concern for oncogenesis.

Objective

This scoping review aims to explore and assess the current literature related to older adult cancer outcomes after a disaster. The present study builds on previous reviews examining the intersections of disasters and cancer care^7,15,17 to characterize the state of the literature pertaining to the following intersection (Fig 1): (1) older adult oncologic outcomes; (2) focusing on both cancer risk and cancer care; (3) in a global context; and (4) differentiating outcomes related to climate, technological, and geophysical disasters. This review is not exclusive to cancer type, to identify the preponderance of evidence for various risk pathways and identify potential gaps in care across this diverse disease group.

FIG 1.

Scoping review conceptual framework.

METHODS

Search Strategy

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for Scoping Reviews guidelines.²² A literature search was conducted between January 3 and February 8, 2022, in PubMed and Web of Science. An additional search conducted in the Cumulated Index to Nursing and Allied Health Literature (CINAHL) and PsycInfo yielded no additional results. The search strategy was iteratively updated to include Medical Subject Heading (MeSH) terms to capture literature related to natural disasters, cancer types, and older adult populations. Additional terms were added to capture natural hazards triggering technological disasters (natech disasters), which refer to the interaction between climate or geophysical events and industrial accidents, such as the 2011 Japan Triple Disaster.²³ The final search strategy included the following terms: ("natural disasters"[MESH] OR natural disasters OR hurricane OR earthquake OR tsunami OR cyclone OR wildfire OR volcan* OR climate induced disasters OR "extreme weather event" OR tornado OR "oil spill" OR "natech" OR "nuclear accident") AND ("neoplasms"[MESH] OR cancer OR oncolog* OR carcinogen* OR "cancer care" OR malignan* OR tumor) AND ("aged"[MESH] OR older adults OR geriatric OR older adult OR elder* OR aging OR older people).

The reference sections of previous systematic and scoping review articles pertaining to disasters and cancer were also reviewed for relevant citations and accessed via Google Scholar.

Screening and Inclusion Criteria

Search results were exported from EndNote X9²⁴ and uploaded into Covidence²⁵ for screening and duplicates removed. Studies that included older adults (older than 65 years) among their study population; included an exposure related to a geophysical, technological, or climate-amplified disaster context; and assessed cancer-related outcomes were included in title/abstract screening. Age >65 years was selected as the cutoff on the basis of WHO convention for defining elderly persons.²⁶ Studies were excluded if they focused exclusively on pediatric or adolescent populations or did not include adults over age 65 years; the disaster context was exclusively related to terrorism, war, or other conflict; outcomes were not related to cancer (eg, vector-borne illness) or human disease (eg, ecologic indicators). Articles examining the effects of occupational exposure during a disaster (eg, effects on first responders, cleanup workers) were excluded. Eligible article types included original peer-reviewed research and reviews in English; letters to the editor, commentaries, and meeting abstracts were excluded.

Titles and abstracts were screened independently by a single reviewer. A subset of articles (5%) were also screened by the senior author (A.A.M.) to establish inter-rater reliability, following guidelines in a recent scoping review which assessed cancer-related outcomes.²⁷ Previous research has suggested that a single reviewer process has a negligible impact on findings of scoping reviews.²⁸

Full-Text Review and Data Extraction

Once title and abstract screening was complete, the authors completed a full-text review to confirm eligibility. Data were then extracted from all full-text articles across nine domains: (1) lead author/year, (2) article title, (3) study design/article type, (4) study objectives (5) description of disaster, (6) type of disaster (climate-amplified, geophysical, technological), (7) geographic area, (8) cancer-related outcomes studied, and (9) outcomes specific to older adults. Study characteristics were summarized using descriptive statistics, and study results were categorized via thematic text analysis.

RESULTS

The database search and review of reference lists identified 791 studies for title and abstract screening. On the basis of the content of the abstract, 147 were selected for full-text review. One hundred twelve studies were excluded during full-text review because they did not meet the criteria for selection. In the end, 35 studies were eligible for data extraction (Fig 2).

FIG 2.

PRISMA diagram. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Study Characteristics

A variety of study designs were included in this scoping review. Sixteen (45.7%) were cohort studies (including prospective and retrospective/historical cohorts), six (17.1%) used cross-sectional designs, and three (8.6%) were qualitative studies. The articles included four reviews (11.3%) and six studies (17.1%) with other study designs, including cost-effectiveness studies, clinical case reports, and a bioethical analysis. The studies encompassed a diversity of environments, countries, and geopolitical regions. Notably, there were no articles focused on disasters or outcomes in Australia, Central/South America, or Africa, which met all inclusion criteria. Articles focused on technological disasters comprised 60% of the final sample (n = 21), followed by climate-amplified disasters (28.6%, n = 10) and geophysical disasters (11.4%, n = 4). There were few studies that focused on older adults specifically; rather, those over age 65 years were most often a subsample in a study with a broader age range.

Cancer-Related Outcomes

The current literature on cancer-related outcomes for older adults in disaster settings can be grouped into three major categories: (1) studies concerned with carcinogenic exposure and cancer incidence related to the disaster event, (2) studies examining changes in access to cancer care and cancer treatment disruptions as a result of the disaster event, and (3) studies exploring the psychosocial experiences of patients with cancer affected by a disaster event. The findings within each category are synthesized and reported below for technological, climate-amplified, and geophysical disasters.

Outcomes Related to Technological Disasters

Twenty-one articles focused on technological disasters, including the Chernobyl nuclear accident (n = 7), the Fukushima Daiichi Nuclear Power Plant accident (n = 10), and the Deepwater Horizon Oil Spill (n = 2; Table 1). Two studies examined the long-term effects of various nuclear events in the twentieth century.

TABLE 1.

Impact of Technological Disasters on Cancer-Related Outcomes (n = 21)

Twelve studies focused on cancer incidence and carcinogenic exposure following a technological disaster. There were mixed findings concerning the impact of radiation exposure on long-term cancer incidence in older adult populations, on the basis of the type of cancer, age at the time of exposure, and geographic proximity to the accident. Two cohort studies following the Chernobyl nuclear accident found that thyroid cancer risk was elevated in individuals exposed to radiation in adulthood and excess thyroid cancer manifested after a longer period of time among older age groups compared with younger cohorts.^29,30 Both studies found statistically significant excess thyroid cancer among females age 40-49 years at the time of the accident living in high-exposure zones in Ukraine.^29,30 However, two other studies focused on breast cancer incidence in Ukraine and found no differences in excess risk on the basis of age at the time of the Chernobyl accident over a 30-year period.^31,32 Studies examining the oncogenic impact of Chernobyl outside Ukraine did not find evidence of increased cancer incidence among older adults.^21,33 An analysis following the Fukushima nuclear accident found that excess cancer mortality was more severe and longer-lasting among elderly populations; however, the authors hypothesize that cancer-related deaths were more likely due to disruption of care rather than radiation exposure.³⁹ In fact, two analyses following the Fukushima nuclear accident found that health risks of emergency evacuation and diabetes were much higher than the cancer risks of radiation exposure for older adults.^34,35

Five studies focused on the impact of the Fukushima nuclear accident on access to cancer care among older adults. Relative length of examination interval postdisaster was significantly higher among adults older than >65 years compared with those younger than 50 years, and patients with an examination interval of 12 months or longer had higher odds of being diagnosed with advanced cancer.^41,42 However, other analyses suggest that old age was not associated with nonparticipation in colorectal cancer screening after a disaster.⁴⁰ Two studies examined health system responses to the Fukushima disaster and found that mortality rates among evacuated elderly people requiring nursing care tripled in the first 3 months after the evacuation compared with that before the accident, but that cancer's long premorbid period made cause-specific mortality difficult to discern.^43,44

Four studies examined the psychosocial experiences of patients with cancer after a technological disaster. Studies conducted in the aftermath of Fukushima suggest that older adult social isolation and poor social support contributed to delays in accessing cancer care.^47,48 Studies conducted after the Deepwater Horizon oil spill and Chernobyl focused on the impact of disaster on illness perception and theories of illness causation. While residents of the Gulf Coast experience toxic frustration and attribute community illnesses—including cancer—to petrochemical disasters,⁴⁵ Russian-speaking patients exposed to Chernobyl exhibited no differences in illness perception or cancer fatalism from unexposed patients.⁴⁶

Outcomes Related to Climate-Amplified Disasters

Ten articles examined the impacts of climate-amplified disasters (Table 2). Eight focused on a single hurricane or typhoon event, including Hurricane Katrina (n = 3), Hurricane Maria (n = 2), Hurricane Sandy (n = 1), Hurricane Harvey (n = 1), and Typhoon Haiyan (n = 1). Two studies reviewed the cancer outcomes of various disaster exposures, including hurricanes, floods, and wildfire.

TABLE 2.

Impact of Climate-Amplified Disasters on Cancer-Related Outcomes (n = 10)

Two papers examined changes in cancer incidence after exposure to a climate-amplified disaster. A Hurricane Katrina study found that 56% of the newly diagnosed patients were over age 65 years.⁴⁹ A narrative review of older adult vulnerability after natural disasters identified literature suggesting that older adults are susceptible to carcinogenic exposures after flooding and wildfire events.⁷

Four papers examined access to cancer care and care disruptions after a climate-amplified disaster. A cross-sectional study of the impact of Hurricane Sandy on gynecologic cancer care identified delays in chemotherapy, radiotherapy, and surgery after the event.⁵³ Analysis of spatiotemporal variation in cancer-specific survival in Louisiana found that individuals diagnosed just after Hurricane Katrina experienced decreased survival times across all cancers, with worse survival among older adults.⁵² A cross-sectional survey of factors affecting access to head and neck cancer care after Hurricane Katrina found that reduced access to cancer care was significantly associated with difficulty in obtaining treatment.⁵¹ Similarly, a case report of emergency medical care in the aftermath of Typhoon Haiyan described the triage process for two older adult patients with head and neck tumors, where limited interventions were able to be performed by the field team.⁵⁰ A review of cancer care for refugees and displaced populations in the aftermath of climate-related disasters found that although older adults are highly vulnerable to negative cancer-related outcomes after a disaster, care of older patients with cancer does not fall within high priorities of international relief and humanitarian agencies because of concerns about cost and perceptions of poor prognosis.¹³

Three studies examined factors contributing to psychosocial outcomes of patients with cancer after a climate-amplified disaster. Cancer survivors experienced high levels of psychological distress and numerous environmental stressors in the aftermath of Hurricane Maria.^54,55 In contrast to the studies following the Fukushima disaster, higher perceived social support among cancer survivors had a significant positive correlation with depression, anxiety, post-traumatic symptoms, distress, and perceived stress.⁵⁴

Outcomes Related to Geophysical Disasters

Four studies assessed cancer outcomes related to geophysical disasters (Table 3), including the 2015 Nepal Earthquake and the Mt. Etna volcanic eruptions in Sicily. Two studies focused on the 2011 Great East Japan Earthquake and tsunami; although this event is part of Japan's triple disaster, these studies were categorized as geophysical because they focused exclusively on the impacts of the earthquake and tsunami (eg, infrastructure damage and health system disruption) rather than the nuclear accident and radiation exposure.

TABLE 3.

Impact of Geophysical Disasters on Cancer-Related Outcomes (n = 4)

A cohort study examined thyroid cancer characteristics and survival rates in Sicily and found that anaplastic thyroid cancer (ATC) incidence is twice high in the provinces surrounding the Mt. Etna volcanic area compared with the rest of the island.⁵⁷ Notably, ATC occurs at a more advanced age compared with other thyroid cancers, with worse prognosis.⁵⁷

Three studies examined the impacts of the earthquake-related disasters on cancer care.^58-60 An analysis following the 2015 Nepal earthquake did not find clinically meaningful differences on the basis of age in the rate of hospital admissions among patients with cancer, yet admission rates were elevated beyond a predisaster level for the 2-year study period after the disaster.⁶⁰ Conversely, an examination of lung cancer hospitalization rates following the Great East Japan Earthquake did not find any differences in rate or mean age of admission in the 2 years pre- and postdisaster.⁵⁸ Finally, an analysis of cervical cancer screening rates in Japan found that coastal areas affected by the earthquake had significantly lower rates compared with inland areas.⁵⁹

DISCUSSION

Disasters have both near-term and long-term impacts on older adult cancer outcomes. In the acute postdisaster period, infrastructure damage, systems disruptions, evacuation, and overburdened hospitals impede access to cancer screening, treatment, and care for older adults. As the studies identified by this scoping review suggest, these disaster-related disruptions worsen older adult cancer–related mortality. However, other cancer-related effects of disaster exposure may not manifest for years, leading to long-term negative health consequences for affected populations.

The mixed findings on the impact of disaster-related radiation exposure on cancer incidence among older adults are likely attributable to both geographic proximity to the event and age at exposure. Thyroid cancer excess among females age 40-49 years at the time of the Chernobyl nuclear disaster suggests a potential combined effect of radiation exposure and changing hormonal status in this age group.²⁹ This is supported by long-term studies of Japanese atomic bomb survivors, which found that radiation risks after exposure in middle age are influenced by promotion of pre-existing premalignant cells or damage.⁶¹ This suggests that radiation-induced cancer risks and initiation differ based on stage of life, indicating the need for studies that incorporate diverse age cohorts after a nuclear disaster.

The long latency period between carcinogenic exposure and cancer outcomes affected the number of studies eligible for this review. Many of the search results related to nuclear accidents (eg, Chernobyl, Fukushima) focused on exposures to individuals younger than 20 years who are thought to be more physiologically susceptible to the effects of radiation; it is estimated that when exposed to the same radiation level, the dose to a child's thyroid is 8 to 9 times that of an adult.⁶² Therefore, many of the study cohorts were too young to be eligible for inclusion in the current review; a 20-year-old exposed to Chernobyl radiation in 1986 would only be 56 years old at the time of the present literature search. Longitudinal cohort studies from earlier nuclear events, such as the 1945 atomic bombing of Hiroshima and Nagasaki, suggest that excess thyroid cancer risk associated with childhood exposure persists even 60 years after exposure, and exposure to ionizing radiation elevates cancer risk throughout the lifespan.^37,38 A 30-year follow-up study of the 1979 Three Mile Island nuclear accident in Pennsylvania similarly identified a greater-than-expected incidence of thyroid cancer in the surrounding counties over time; although the study cohort is too young for the current study, the oldest members are rapidly approaching older adulthood.⁶³ The late effects and future cancer burden for populations exposed to Chernobyl, Fukushima, and other nuclear events will be of particular concern as these populations age.

The latency between exposure and disease detection may also explain the unexpected lack of studies related to wildfire eligible for inclusion in this review. Recent research suggests that older adults may be particularly susceptible to the negative health consequences of wildfire smoke; exposure to PM_2.5 is associated with increased hospitalization and mortality among adults 65 years or older.^7,64,65 Recent analyses found that individuals exposed to a wildfire within 50 km in the past 10 years had a 4.9% (95% CI, 2.8 to 7.1) relatively higher incidence of lung cancer than unexposed populations and a 10% (95% CI, 2.6 to 17.9) relatively higher incidence of brain tumors.⁶⁶ Although this indicates a relationship between wildfire exposure and cancer incidence, the authors did not differentiate incidence by age at exposure. The 10-year latency period, suggested in other studies as an appropriate minimum lag time for examining the relationship between cancer incidence and exposure to environmental carcinogens,^30,66,67 means that many wildfire events have occurred too recently to determine their carcinogenic effects, highlighting the need for future longitudinal trials among wildfire-exposed populations.

Although previous literature has identified the negative psychosocial impact of disasters on older adults generally,¹¹ the studies reviewed here suggest that older adults with cancer might have worse psychological outcomes than those without a cancer diagnosis. This review also highlighted a need for long-term studies concerning unique psychosocial needs of older adult patients with cancer after a disaster event, particularly those who are displaced by disaster and need to receive cancer care in an unfamiliar location far from social networks. Furthermore, there is a need for studies that longitudinally examine psychological outcomes among older adults who experience a carcinogenic exposure event.³⁷ The differences in illness attribution and cancer attitudes between older adults exposed to the Deepwater Horizon Oil Spill and Chernobyl nuclear accident suggest the need for further studies on how disasters differentially affect experiences of patients with cancer and recovery perceptions and how these are influenced by sociocultural context.^45,46

Very few studies in this review focused on disasters situated in low- and middle-income countries (LMICs). This may be partially attributed to the specific focus on older adults; high-income countries (HICs) such as the United States and Japan have more rapidly aging populations compared with many LMICs.⁴ However, the largest global increases in cancer incidence are now concentrated in LMICs, with higher cancer-related mortality rates compared with HICs because of structural barriers to timely and accessible quality care.² Compounding this issue is LMICs’ vulnerability to the impacts of climate changes, including climate-amplified disasters.^17,68 As this review identified, there is a lack of focus on cancer care in global disaster relief because of costliness and perceptions of poor prognosis,¹³ meaning that many socially vulnerable patients with cancer—including older adults—in low-resource settings are at risk of being triaged out in postdisaster scenarios. Thus, a focus on disaster-related older adult cancer outcomes in LMIC settings is urgently needed.

The results of this scoping review have important implications for disaster preparedness and response. Findings from the Fukushima studies suggest the need for evacuation plans, which consider both near-term and long-term risk tradeoffs for older adults; evacuation plans, which do not take into account the impacts of older adult isolation and displacement, may worsen access to cancer care and overall survival. Furthermore, while current guidelines do not recommend thyroid radiation prophylaxis (potassium iodide) for adults over age 60 years after an exposure event,⁶² there is emerging evidence that radiation exposure might still have oncogenic effects among older adults, suggesting the need for enhanced, age-stratified cancer screening programs after natech disasters. Finally, there is a need to plan for the long-term psychosocial needs of older adult patients with cancer, particularly those displaced by disaster. For instance, studies among individuals in the Russian-speaking diaspora exposed to Chernobyl reveal unique psychosocial and medical needs, which may be exacerbated by increased cancer burden as this population ages.⁶⁹

The present review has important implications for older adult cancer outcomes in other disaster settings. Across studies, older adults with cancer were not prioritized in humanitarian responses to climate-amplified weather events.^13,50 Studies among refugee populations in Syria, Jordan, and Ukraine^70-73 suggest that older adult patients with cancer face similar barriers to care in armed conflict scenarios. Analyses of medical humanitarian efforts in Jordan underscore the tension between short-term crisis response and planning for long-term displacement and management of chronic conditions among older refugee populations.^71,72 As the reviewed literature suggests, this tension may be amplified when the humanitarian crisis doubles as a carcinogenic exposure event.⁴³ Given the elevated cancer burden among Ukrainians exposed to the Chernobyl nuclear disaster,⁷⁴ the disruption of oncologic services because of the 2022 armed conflict in Ukraine is an urgent concern. A recent analysis estimated 1,118 excess breast cancer deaths because of armed conflict–related treatment delays.⁷³ Disruptions of medical supply chains, lack of access to chemotherapy, and limited mobility of older adult populations will enhance these delays.

The results of this scoping review also include valuable lessons for older adult cancer care during the ongoing COVID-19 pandemic. The spring 2020 COVID-19 surge in the United States caused a substantial decrease in cancer screenings, visits, therapy, and surgeries among the Medicare fee-for-service population (ie, adults 65 years and older).⁷⁵ Older adults might have disproportionately experienced delayed care in response to COVID-19; a national survey found that urban-based providers in the United States were more likely to prioritize treatment for younger patients (P = .048) and patient age was listed among the top five factors in deciding to postpone cancer treatment.⁷⁶ In France, health authorities recommended prioritizing cancer treatment for individuals 60 years and younger.⁷⁷ The present scoping review suggests that these disruptions to treatment may worsen cancer-related mortality among older adult populations.

From a disaster preparedness perspective, there is a need to develop age-specific care management guidelines to ensure safe continuity of cancer care. In a cross-sectional survey of United States cancer care providers, only 15.4% of respondents reported access to guidelines for the management of older adults with cancer during the COVID-19 crisis, enhancing treatment delays and concerns about patient safety.⁷⁸ As the present review finds, older adult social isolation and poor social support contribute to delays in accessing cancer care during and after a disaster. Although social distancing is critical for immunocompromised populations during an infectious disease pandemic, interventions to support the psychosocial health of patients with cancer are needed. Virtual mind-body programming, for example, has been shown to help older adult patients with cancer foster social relationships during isolation and cope with COVID-19–related stressors.⁷⁹

This review has several limitations. The exclusion of commentaries, letters to the editor, and brief reports might have inadvertently omitted valuable information pertaining to cancer care in the acute disaster management phase.¹⁶ Furthermore, excluding terrorism events meant that potential sources of population-level carcinogenic exposure were not included. Studies pertaining to changes in long-term cancer incidence may be limited by survivor bias; disaster-exposed individuals need to survive into older adulthood to determine the association between the carcinogenic event and cancer incidence. Finally, excluding non-English language full-text articles might have limited the geographic diversity of the findings. However, the focus on multiple disaster types, and their impact on older populations specifically, is a strength of this review.

In conclusion, evidence suggests that disasters worsen cancer-related outcomes among older adults by disrupting continuity of care and access to timely treatment. There are mixed results regarding the long-term impact of disasters on older adult cancer incidence, indicating the need for longitudinal follow-up after disaster events. Future studies should also examine the long-term psychological impacts of disasters and develop mitigation plans, which attend to the unique needs of this population.

AUTHOR CONTRIBUTIONS

Conception and Design: All authors

Administrative support: Kathleen A. Lynch

Collection and assembly of data: Kathleen A. Lynch

Data analysis and interpretation: All authors

Manuscript writing: All authors

Final approval of manuscript: All authors

Accountable for all aspects of the work: All authors

AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

The following represents disclosure information provided by authors of this manuscript. All relationships are considered compensated unless otherwise noted. Relationships are self-held unless noted. I = Immediate Family Member, Inst = My Institution. Relationships may not relate to the subject matter of this manuscript. For more information about ASCO's conflict of interest policy, please refer to www.asco.org/rwc or ascopubs.org/go/authors/author-center.

Open Payments is a public database containing information reported by companies about payments made to US-licensed physicians (Open Payments).

No potential conflicts of interest were reported.