Shenbai Granules for Preventing Malignant Transformation of High-risk Colorectal Adenomas

High-risk colorectal adenomas (HR-CRAs) are a recognized precursor lesion for colorectal cancer, with 25-40% of patients developing metachronous adenomas within 3 years after endoscopic resection. Low-dose aspirin is the only agent supported by high-level evidence for reducing the incidence of metachronous HR-CRAs, but its use is limited by bleeding risks. Although previous studies on the traditional Chinese medicine compound Shenbai Granules (SBG) have suggested its potential in preventing metachronous HR-CRAs, sufficient evidence from randomised controlled trials (RCTs) is still lacking. This trial aims to confirm the efficacy and safety of SBG in preventing the development of metachronous adenomas and subsequent carcinogenesis, and to identify clinical predictors of treatment response to define the optimal target population. This multicentre, randomised, double-blind, placebo-controlled trial will enroll 450 patients with endoscopically resected HR-CRAs. Participants will be randomly allocated 1:1 to receive either SBG (n=225) or a matching placebo (n=225). The trial comprises a 14-day screening period, a 6-month treatment phase, and a 30-month surveillance phase, including four on-site visits and one telephone follow-up. The primary endpoint is the three-year cumulative incidence of metachronous HR-CRA. Secondary endpoints include the incidence of metachronous low-risk adenomas and serrated lesions within the same 3-year window, cumulative number and size of lesions, anatomic distribution, histopathology, and the incidence of colorectal cancer.