Cannabis use after a cancer diagnosis in a population-based sample of cancer survivors.

Purpose: This study aimed to characterize the prevalence and correlates of cannabis use and the methods and reasons for use among recently diagnosed cancer survivors in a population sample within Washington state.

Methods: We identified individuals diagnosed with invasive cancers in the prior 6 to 17 months from April 2020 to December 2020 using the Seattle-Puget Sound Surveillance, Epidemiology, and End Results (SEER) cancer registry. Participants (n = 1,515) completed a questionnaire, including demographics, medical history, cannabis use, and other substance use. Cancer characteristics and date of diagnosis were obtained from SEER registry data. We calculated weighted prevalence estimates and logistic regression models to evaluate correlates of cannabis use.

Results: Overall, 41.3% of survivors reported cannabis use at any time after diagnosis, most commonly via edibles (60.5%) and smoking (43.8%). The most frequently reported reasons for use were sleep (54.5%), mood, stress, anxiety, and depression (44.3%), pain (42.3%), and recreation (42.3%). Cannabis use was associated with younger age, race (White vs. Asian), less education, former or current smoking, consuming more than 2 alcohol-containing drinks per day, having late-stage cancer, and cancer site.

Conclusion: In this first evaluation of cannabis use in a registry-linked, population-based sample of survivors of all cancer types, based in a state where recreational and medical cannabis have been legal for a decade, approximately 2 in 5 survivors reported post-diagnosis use. Given how common cannabis use is among cancer survivors, there is a great need to understand its impact on cancer treatment outcomes and the overall health of cancer survivors.