Cannabis Dependence Not Linked to Higher Cancer Mortality, Unlike Alcohol and Opioids
Among 22,763 cancer patients, cannabis dependence showed no significant association with mortality, while alcohol and opioid dependence were linked to significantly higher death rates even after adjusting for tumor stage.
Quick Facts
What This Study Found
Cannabis dependence was not significantly associated with mortality among cancer patients. In contrast, alcohol and opioid dependence remained significant predictors of mortality after adjusting for tumor stage. Tobacco dependence showed an attenuated association after stage adjustment, suggesting confounding by later-stage diagnosis.
Key Numbers
22,763 cancer patients; cannabis dependence not significant for mortality; alcohol and opioid dependence significant in adjusted models; tumor stage adjustment reduced opioid and tobacco hazard ratios.
How They Did This
Retrospective analysis of 22,763 cancer patients aged 18+ from UC San Diego Health. Substance dependence identified from electronic health records. Cox proportional hazards models adjusted for tumor staging (TNM system with imputed missing data).
Why This Research Matters
Cancer patients sometimes worry that cannabis use might worsen their prognosis. This large study suggests cannabis dependence, unlike alcohol or opioid dependence, does not appear to independently increase mortality risk in cancer patients.
The Bigger Picture
As more cancer patients use cannabis for symptom management, understanding whether it affects survival is critical. This study adds to evidence suggesting cannabis does not worsen cancer outcomes, though the small number of cannabis-dependent patients limits statistical power.
What This Study Doesn't Tell Us
Substance dependence from clinical notes may undercount actual use. Small sample of cannabis-dependent patients limits power. Single health system. Cannot distinguish between types/amounts of cannabis use. Observational design with potential unmeasured confounders.
Questions This Raises
- ?Would a larger sample of cannabis-dependent cancer patients reveal a mortality signal?
- ?Does cannabis type or consumption method matter for cancer outcomes?
Trust & Context
- Key Stat:
- Cannabis dependence not linked to cancer mortality
- Evidence Grade:
- Large retrospective cohort with tumor stage adjustment, but limited by small cannabis-dependent sample and observational design.
- Study Age:
- 2025 publication
- Original Title:
- Influence of Substance Use Disorders on Mortality in a Systemwide Cohort of Cancer Patients.
- Published In:
- Psycho-oncology, 34(8), e70243 (2025)
- Database ID:
- RTHC-06821
Evidence Hierarchy
Frequently Asked Questions
Does cannabis use affect cancer survival?
In this study of 22,763 cancer patients, cannabis dependence was not significantly associated with mortality. However, the small number of cannabis-dependent patients means this finding should be interpreted cautiously.
Which substances are linked to worse cancer outcomes?
Alcohol and opioid dependence were significantly associated with higher cancer mortality even after accounting for tumor stage. Cannabis and amphetamine dependence were not, though both had limited sample sizes.
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Cite This Study
https://rethinkthc.com/research/RTHC-06821APA
Khoyilar, Shawnly; Purushothaman, Vidya; Cuomo, Raphael E. (2025). Influence of Substance Use Disorders on Mortality in a Systemwide Cohort of Cancer Patients.. Psycho-oncology, 34(8), e70243. https://doi.org/10.1002/pon.70243
MLA
Khoyilar, Shawnly, et al. "Influence of Substance Use Disorders on Mortality in a Systemwide Cohort of Cancer Patients.." Psycho-oncology, 2025. https://doi.org/10.1002/pon.70243
RethinkTHC
RethinkTHC Research Database. "Influence of Substance Use Disorders on Mortality in a Syste..." RTHC-06821. Retrieved from https://rethinkthc.com/research/khoyilar-2025-influence-of-substance-use
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.