The use of cannabis appears to result in a lower incidence of basal cell carcinoma (BCC) over 10 years, but not cutaneous squamous cell carcinoma (cSCC) or malignant melanoma (MM), suggests a recent study presented at AAD 2026.
“These findings suggest potential biologic effects of cannabinoids on cutaneous carcinogenesis,” said lead study author Dr Stefano M DiCenso, Case Western Reserve University School of Medicine, Cleveland, Ohio, US.
“However, further prospective and mechanistic studies are needed to clarify causality and inform clinical relevance,” he added.
DiCenso and his team used the TriNetX platform to identify and match adults aged ≥30 years with documented cannabis use (n=74,276) with controls (n=74,276) based on demographics and comorbidities. The mean age of participants was 47.3 years, and more than half were male (52.3 percent) and White (60.3 percent). [AAD 2026, abstract 70596]
For 10 years, DiCenso and colleagues followed the participants for outcomes including incident MM, cSCC, and BCC, with removal of benign lesions serving as a negative control. They estimated hazard ratios (HRs) with 95 percent confidence intervals (CIs) using univariate Cox proportional hazards models.
Cannabis use resulted in a 22-percent reduction in the risk of BCC (HR, 0.78, 95 percent CI, 0.69‒0.89; p=0.0002). This protective benefit persisted in sensitivity analyses restricting follow-up to 1‒10 years (HR, 0.66, 95 percent CI, 0.58‒0.77; p<0.0001) and among patients with a diagnosis of cannabis abuse (HR, 0.66, 95 percent CI, 0.54‒0.82; p<0.0001).
In subgroup analyses, the use of cannabis reduced the risk of BCC by 27 percent in males (HR, 0.73, 95 percent CI, 0.62‒0.86) and by 18 percent in White patients (HR, 0.82, 95 percent CI, 0.72‒0.95).
There were no differences seen for cSCC or MM, but one sensitivity analysis revealed a 27-percent decrease in MM risk (HR, 0.73, 95 percent CI, 0.57‒0.95). Moreover, no differences were noted for benign lesion removals.
“Cannabis use was associated with decreased BCC incidence but not cSCC or MM,” said DiCenso and colleagues, noting the need for further prospective and mechanistic studies before making any clinical or policy recommendations.
Cutaneous cells
Many types of cutaneous cells, including keratinocytes down to the basal layer, melanocytes, immune cells, and sensory neurons, express cannabinoid (CB) receptors. [Am J Clin Dermatol 2018;20:167-180; J Biol Chem 2012;287:15466-15478]
In several in vitro studies of MM and cSCC, CB activity was found to reduce cytokine and chemokine release, as well as modulate apoptosis and proliferation in malignant cells. [Dermatology 2015;135:1629-1637; J Immunol 2013;190:4929-4936; Cancers 2022;14:1769]
“Despite an increase in the self-reported use of cannabis in the US and other high-income countries of 120 percent from 2008 to 2022, no clinical studies have assessed the risk of cannabis use and skin cancer,” according to DiCenso and colleagues. [Addiction 2024;119:1648-1652]
“Dermatologists are increasingly asked for advice on this topic, emphasizing the unmet need for research,” they added.