Endoscopic resection after neoadjuvant therapy for advanced rectal cancer with near-complete response: a retrospective multicentre case series

Background Radical surgery after neoadjuvant therapy remains standard for locally advanced rectal cancer but carries substantial postoperative morbidity. With near-complete clinical response (near-cCR) and superficial-appearing residual disease, endoscopic resection may offer an organ-preserving alternative, although evidence for safety and oncological efficacy remains limited. Objective To evaluate feasibility, safety and oncological outcomes of endoscopic resection for superficial residual rectal neoplasia in patients with near-cCR after various neoadjuvant therapies. Design Multicentre retrospective case series from 12 centres (2018–2025) of patients with presumed superficial residual neoplasia based on endoscopy and cross-sectional imaging excluding lymph node involvement or distant metastases. Primary outcomes: technical success, safety, R0 resection and recurrence. Results Among 42 patients (median age 68 years) treated with endoscopic submucosal dissection (43%) or deeper resection techniques, en bloc and R0 resection rates were 97.6% and 85.4%, respectively. Histology showed hyperplasia/adenoma in 52.4%, T1 cancer in 35.7% and ≥T2 cancer in 11.9%, with cancer in 28% of Japanese Narrow Band Imaging Expert Team (JNET) type 2 lesions (all but one T1) and 80% of JNET type 3 lesions, one-third >T1. Six underwent surgery for incomplete resection or lesion risk features. Among remaining patients, median follow-up was 29 months. Recurrence occurred in 16% (four endoluminal, one locoregional, one solitary lung metastasis). Adverse events occurred in 7.3%, all grade ≤2; major low anterior resection syndrome occurred in 10% of 29 evaluable patients. Conclusions Endoscopic resection appears feasible for selected near-cCR patients after neoadjuvant therapy. Residual tumour extent remains difficult to predict, but JNET type 3 may indicate disease less amenable to endoscopic resection.