Mechanisms of Food Insecurity Following a Cancer Diagnosis: A Systematic Review and Implications for Measurement.

CONTEXT: Food insecurity (FI) is an emerging concern for cancer survivors that may arise through multiple mechanisms across the cancer care continuum. Financial challenges-such as increased medical expenses and employment disruptions-are well documented, but FI may also arise from nonfinancial factors, including illness- or treatment-related physical limitations affecting food procurement and preparation, transportation or food access challenges, social isolation, and limited access to nutrition care. OBJECTIVE: This PROSPERO-registered systematic review identified factors affecting FI following a cancer diagnosis, including financial and nonfinancial mechanisms. DATA SOURCES: A comprehensive search of Web of Science, Ovid MEDLINE, EMBASE, CABI, and CINAHL identified studies of individuals with active or prior cancer in the United States and published through November 2024. DATA EXTRACTION: Two reviewers independently screened the studies and conducted quality and risk-of-bias appraisal, with disagreements resolved by a third reviewer. Data were extracted on population and setting characteristics, FI measurement tools, FI prevalence, evidence of financial and nonfinancial mechanisms, and subgroup differences. DATA ANALYSIS: The results were categorized by study design. Twenty-one studies met the inclusion criteria, with FI prevalence ranging from 6.2% to 72.7%. Most studies (20/21) examined financial mechanisms, documenting income loss, work disruptions, increased medical expenses, and material hardship, disproportionately affecting younger adults, lower-income individuals, and racially and ethnically minoritized populations. Nonfinancial contributors were rarely measured explicitly (1/21), though 9 studies measured transportation barriers, physical or mobility limitations, and social isolation. Only 6 studies assessed FI longitudinally, limiting causal inference. CONCLUSION: Food insecurity screening and measurement practices that emphasize financial access may underestimate the needs of cancer survivors. Integrating both financial and nonfinancial mechanisms into research and clinical practice may strengthen nutritional care and improve health outcomes. Interpretation of the existing evidence is constrained by predominantly cross-sectional designs and inconsistent FI assessment timing, underscoring the need for more rigorous longitudinal research. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration No. CRD42024585815.