Post-diagnosis cannabis use and its association with health status and quality of life in cancer survivors.

Kasiri N.; McDaniels-Davidson C.; Doran N.; Patel S.; Strong D.; Parada H. · Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer · 2026

**Background & Methods** This cross-sectional study surveyed 652 cancer survivors (weighted sample: 58.6% non-Hispanic White, 58.5% female, mean age ≥65 years) who received care at an NCI-designated cancer center between 2018-2019. Participants completed an online survey in 2022 assessing post-diagnosis cannabis use and self-rated physical health, mental health, and quality of life (QoL), with survey-weighted logistic regression used to estimate adjusted odds ratios and explore effect modification by cancer stage, treatment status, and pre-diagnosis cannabis use. **Key Findings** • Cancer survivors reporting average or below average mental health had significantly higher odds of post-diagnosis cannabis use (OR=1.88; 95% CI=1.13-3.11), representing the only statistically significant association identified in the study. • Most survivors reported above average mental health (67.2%) and QoL (64.2%), while approximately half (47.1%) reported above average physical health; positive but non-significant associations were observed between cannabis use and both physical health (OR=1.38; 95% CI=0.85-2.24) and QoL (OR=1.24; 95% CI=0.75-2.05). • Associations between cannabis use and health outcomes did not significantly differ by cancer stage, active treatment status, or pre-diagnosis cannabis use history, suggesting consistent patterns across subgroups. **Dosage & Administration** Not reported. **Safety & Adverse Effects** Not reported. **Evidence Quality** This study represents observational evidence with several important limitations. The response rate of 16.1% (954/5,901 invitations) introduces potential selection bias, as survivors motivated to report cannabis use or health concerns may be overrepresented. The cross-sectional design precludes causal inference regarding whether poor mental health leads to cannabis use or vice versa. Self-reported outcomes without clinical verification, single-item assessments of health status/QoL lacking validated instruments, and lack of information on cannabis dose, frequency, cannabinoid composition, and route of administration limit clinical applicability. The study was underpowered to detect differences in physical health and QoL associations. While weighted to represent the cancer center population, generalizability to broader cancer survivor populations remains uncertain. This represents Level III evidence suitable for hypothesis generation rather than clinical decision-making, highlighting the need for prospective, longitudinal studies with validated outcome measures and standardized cannabis exposure assessment.

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