Local excision after neoadjuvant chemoradiotherapy for mid and low rectal cancer: a multicentric French study from the GRECCAR group.

AIM: A complete or subcomplete tumour response (CTR) is observed in 10%-25% of patients with mid/low rectal cancer after neoadjuvant chemoradiotherapy (CRT). The aim of our study was to report a multicentric French experience in local excision (LE) after CRT. METHOD: All patients who underwent LE for mid/low rectal cancer with suspected CTR after CRT, from 2006 to 2019 in seven GRECCAR centres were included. LE was considered adequate if the specimen showed a ypT0/Tis/T1R0 tumour, otherwise, a completion total mesorectal excision (TME) was discussed. Morbi-mortality, functional results and oncological outcomes were studied. RESULTS: A total of 257 patients were included. LE specimens showed 36% ypT0, 4% ypTis and 19% ypT1. Thus, 108 patients (42%) had theoretical indication of completion TME, which was performed in only 42 patients. Overall, 30-day morbidity after LE was 11%, including 2% Clavien-Dindo grade III or IV complications. After completion TME, 47% described major low anterior resection syndrome versus 5% after LE alone (p < 0.001). After a mean follow-up of 4 years (range 2-6 years), the recurrence rate was 11% after LE, 32% after completion TME and 20% in patients for whom completion TME was indicated but not performed (p = 0.021). CONCLUSION: TME remains the gold standard for mid/low rectal cancer after CRT. LE in selected patients is safe for operative and functional, but also oncological, results. However, completion TME was indicated in 42% of patients after LE, highlighting the difficulty of the preoperative diagnosis of CTR after CRT.