Chemoradiation and consolidation chemotherapy for rectal cancer provides a high rate of organ preservation with a very good long-term oncological outcome: a single-center cohort series

Aim To report long-term oncological outcomes and organ preservation rate with a chemoradiotherapy-consolidation chemotherapy (CRT-CNCT) treatment for locally advanced rectal cancer (LARC). Method Retrospective analysis of prospectively maintained database was performed. Oncological outcomes of mid-low LARC patients (n=60) were analyzed after a follow-up of 63 (50-83) months. Patients with clinical complete response (cCR) were treated with the watch-and-wait (WW) protocol. Patients who could not achieve cCR were treated with total mesorectal excision (TME) or local excision (LE). Results Thirty-nine (65%) patients who achieved cCR were treated with the WW protocol. TME was performed in 15 (25%) patients and LE was performed in 6 (10%) patients. During the follow-up period, 10 (25.6%) patients in the WW group had regrowth (RG) and 3 (7.7%) had distant metastasis (DM). Five-year overall survival (OS) and disease-free survival (DFS) were 90.1% and 71.6%, respectively, in the WW group. Five-year OS and DFS were 94.9% (95% CI: 88-100%) and 80% (95% CI: 55.2-100%), respectively, in the RG group. For all patients (n=60), 5-year TME-free DFS was 57.3% (95% CI: 44.3-70.2%) and organ preservation-adapted DFS was 77.5% (95% CI: 66.4-88.4%). For the WW group (n=39), 5-year TME-free DFS was 77.5% (95% CI: 63.2-91.8%) and organ preservation-adapted DFS was 85.0% (95% CI: 72.3-97.8%). Conclusion CRT-CNCT provides cCR as high as 2/3 of LARC patients. Regrowths, developed during follow-up, can be successfully salvaged without causing oncological disadvantage if strict surveillance is performed. Keywords: Watch and wait, Non-operative management, Rectal cancer, Clinical complete response, Pathological complete response, Total neoadjuvant chemoradiotherapy