Injectable CBD Implant Shows Promise in Treating Aggressive Breast Cancer, Study Finds

Researchers at the University of Madrid developed an in situ forming implant (ISFI) designed to release CBD—a non-psychoactive component of cannabis—over a period of two months. TNBC, which accounts for up to 20% of breast cancer cases and disproportionately affects younger women, remains one of the most aggressive and treatment-resistant forms of breast cancer.

The research team tested several formulations, ultimately selecting one containing 10 mg of CBD and 100 mg of polycaprolactone (PCL) as the most effective. In laboratory studies, this formulation, known as 10-CB-ISFI, significantly inhibited the growth and migration of TNBC cell lines and blocked the development of blood vessels in tumor models—an effect known as antiangiogenesis. In experiments using the chorioallantoic membrane (CAM) model, a single injection of 10-CB-ISFI was as effective at reducing tumor growth as daily doses of CBD in solution, both achieving roughly 60% inhibition. Notably, the implant’s antiangiogenic effect was stronger than that of the CBD solution, suggesting a superior therapeutic profile.

Researchers say the long-acting implant could be administered during neoadjuvant chemotherapy, potentially enhancing existing treatments while minimizing systemic side effects.

“These findings support the potential of CBD-based implants as a complementary strategy for TNBC,” the authors wrote, though they noted further studies are needed to advance the technology toward clinical use.