Node-Sparing Short-Course Radiation Combined With Capecitabine and PD-1/CTLA-4 for MSS Early Rectal Cancer

This is a single-arm, prospective, multicenter study evaluating a novel neoadjuvant treatment strategy for patients with early, mid-low rectal adenocarcinoma that is microsatellite stable (MSS). Instead of irradiating regional lymph nodes, we deliver short-course radiotherapy (25 Gy in 5 fractions) exclusively to the primary tumor ("lymph-node-sparing" approach), immediately followed by four 3-week cycles of capecitabine plus combined PD-1/CTLA-4 immune checkpoint inhibitors. Two weeks after completing chemo-immunotherapy, tumor response is assessed. Patients who achieve a clinical complete response may enter a "watch-and-wait" program; others will undergo local excision or total mesorectal excision (TME) as appropriate. The primary endpoint is the rate of complete response (clinical and pathological). Secondary endpoints include organ-preservation rate, 3-year local recurrence, 3-year disease-free and overall survival, toxicity, and quality-of-life measures. Results from a pilot study suggest that this regimen may substantially improve complete response rates while reducing radiation-related toxicity, potentially allowing more patients to avoid radical surgery and permanent stoma.

NCT Number	NCT07068763
Lead Sponsor	Sir Run Run Shaw Hospital
Conditions	Rectal Cancer
Enrollment	52 participants
Start Date	2025-10-09
Primary Completion	2026-12-31 (estimated)
Study Completion	2029-12-31 (estimated)
Updated on ClinicalTrials.gov	2026-01-06