Medical cannabis and its effect on oncological outcomes in patients with ovarian cancer treated with PARP inhibitors

Abstract

Background: Poly (ADP-ribose) polymerase inhibitors (PARPi) play a pivotal role in ovarian cancer management. With medical cannabis emerging as a novel component of supportive care, this study investigated the impact of medical cannabis use on oncological outcomes in patients with ovarian cancer undergoing PARPi therapy.

Methods: The study included patients from a single institution database treated for ovarian cancer between January 2014 and January 2020 who received PARPi maintenance therapy in a first-line or recurrent disease setting after a confirmed response to platinum-based treatment. The study categorized patients as cannabis users and cannabis-naïve. Univariate and multivariate Cox regression analysis and the Kaplan-Meier method were used to assess the effects of medical cannabis use on the duration of PARPi therapy, progression-free survival, and overall survival.

Results: Among the eligible patients (n=93), most were cannabis-naïve (69%, n=64) while the rest used medical cannabis (31%, n=29). Medical cannabis use rates were comparable for patients receiving PARPi therapy post-primary treatment or for recurrence (42%, n=9, vs 27%, n=20; p=0.1). Both groups exhibited similar median duration for PARPi therapy (12.1 vs 9.5 months; p=0.89) and progression-free survival (20 vs 21 months; p=0.83). Kaplan-Meier analysis detected no differences in progression-free survival associated with cannabis use. Although cannabis users had an extended overall survival compared with the cannabis-naïve group (129.3 vs 99 months; p=0.03), cannabis use was insignificant for overall survival on multivariate analysis (p=0.10). Multivariate analysis showed stage IV at diagnosis (p=0.02) to be the sole factor associated with progression-free survival (p=0.02).

Conclusion: Medical cannabis usage in patients receiving PARPi treatment showed no association with duration of PARPi therapy, progression-free survival, or overall survival.

Keywords: BRCA1 protein; BRCA2 protein; ovarian cancer; quality of life (PRO)/palliative care.