THC & Cancer: Current Evidence on Antitumor Effects

Preclinical studies show cannabinoids (THC, CBD) have potential antitumor properties in cell and animal models, but no clinical evidence supports injecting THC into tumors as cancer treatment.

Preclinical Mechanisms

• CB1/CB2 receptor activation → apoptosis, autophagy, cell‑cycle arrest
• Inhibition of angiogenesis (VEGF downregulation)
• Reduced invasion/metastasis (MMP inhibition)
• Modulation of immune microenvironment

Clinical Reality

• No Phase III trials demonstrating tumor regression in humans.
• Cannabinoids used clinically for symptom management: chemotherapy‑induced nausea/vomiting (CINV), cancer pain, appetite stimulation.
• Rick Simpson Oil (RSO) and similar unregulated preparations lack standardization, dosing, safety data.
• Intratumoral injection risks: infection, hemorrhage, seeding, unknown pharmacokinetics.

Ongoing Research

• Combination with immunotherapy, radiotherapy, targeted agents.
• Synthetic cannabinoids with improved therapeutic index.
• Biomarker‑driven patient selection.

Bottom Line

THC is not a proven cancer cure. Patients should discuss cannabis use with oncology team to manage symptoms safely and avoid interactions.