Chinese Study Finds CBD Effects in Mouse Models of Colorectal Cancer

A 2023 study by researchers in China reported that cannabidiol (CBD) altered immune-cell behavior and slowed tumor growth in mouse models of colorectal cancer. The findings were preclinical: they did not demonstrate that CBD treats colorectal cancer in people or improves patients’ response to immunotherapy.

What the Researchers Found

The study, published in the Journal of Pharmaceutical Analysis, used single-cell techniques to examine the tumor environment. Researchers focused on macrophages, immune cells whose behavior can help or hinder a tumor’s growth.

CBD treatment shifted macrophage populations away from M2-like characteristics and toward M1-like characteristics in the experimental tumors. The researchers also observed changes in macrophage energy metabolism and signaling, including inhibition of the PI3K-Akt pathway. In transplanted-tumor mouse experiments, combining CBD with an anti-PD-1 immunotherapy produced a stronger response.

These findings suggest a mechanism worth investigating. They do not establish a safe or effective CBD regimen for a person with cancer.

Why the Mouse Results Need Caution

A tumor model cannot reproduce every feature of human cancer, a patient’s immune system, or concurrent treatments. Effects observed in mice need appropriate human testing before researchers can determine whether benefits outweigh harms. Laboratory findings about CBD combined with other cancer treatments require the same distinction.

This report concerns a specific 2023 experiment. It should not be read as a recommendation to buy CBD oil or add it to immunotherapy, nor as evidence that commercial CBD products reproduce the experimental treatment.

What This Means for Cancer Care

The American Society of Clinical Oncology’s guideline recommends against replacing cancer-directed treatment with cannabis or cannabinoids. It also recommends against using them to augment cancer-directed treatment outside a clinical trial.

People considering CBD should discuss it with their oncology team, including why they want to use it and which medicines they take. Symptom management and treatment aimed at controlling a tumor are separate goals. This study supports further research into the latter; it does not establish a clinical benefit.