Berberine Cuts Colon Polyp Recurrence in Half Over Six Years After Treatment Ends

Colorectal cancer typically begins as adenomatous polyps, which recur at high rates after endoscopic removal. Finding safe, effective chemopreventive agents to interrupt this cycle is a major clinical priority. Berberine — a plant alkaloid derived from the Chinese herb Coptis chinensis, long used for gastrointestinal conditions — emerged from prior research as a candidate due to its ability to modulate colorectal tumorigenesis pathways and gut microbiota composition.

The original Chemoprevention of Berberine in Adenoma Recurrence (CBAR) trial (NCT02226185) was a double-blind, randomized, placebo-controlled, multicenter study showing that 2 years of berberine supplementation reduced adenoma recurrence (36% vs. 47%) with no serious adverse events. The current CBAR Follow-up Extension (CBAR-FE) study is a retrospective cohort analysis of those same participants over a median total follow-up of 78 months (approximately 6.5 years) — critically, without any ongoing supplementation.

Of the 895 patients who completed the original 2-year trial, 781 were recruited into the follow-up, and 648 underwent at least one colonoscopy during the extended period. Baseline characteristics — including age, sex, BMI, smoking, family history of colorectal cancer, and colonoscopy timing — were well balanced between groups. In the primary analysis, colorectal adenoma recurrence occurred in 34.7% of the berberine group versus 52.1% of the placebo group (adjusted HR 0.58; 95% CI 0.45–0.74; p < 0.001). Broader colorectal neoplasm occurrence (including serrated lesions and inflammatory polyps) was also significantly lower: 63.4% vs. 71.0% (adjusted HR 0.75; 95% CI 0.62–0.91; p = 0.004). The protective effect was not immediately apparent but reached statistical significance by the third year post-treatment and remained stable from year five onward.

These findings are notable because they suggest a durable, possibly epigenetic or microbiome-mediated mechanism rather than a simple drug-present effect. Berberine's ability to reshape gut microbial composition and inhibit inflammatory and proliferative signaling pathways may set in motion lasting changes that suppress adenoma regrowth long after the treatment window closes.

Implications for clinical practice are significant: berberine is inexpensive, widely available, and has a well-established safety profile, making it a realistic candidate for post-polypectomy chemoprevention in populations at elevated colorectal cancer risk. However, the retrospective observational design of the follow-up phase, potential selection bias among those who underwent colonoscopy, and the predominantly Chinese study population limit the generalizability of these findings. Prospective confirmation in diverse populations is needed before broad clinical adoption.