Neoadjuvant CAPOX and bevacizumab alone for locally advanced rectal cancer: long-term results from the N-SOG 03 trial

Background Neoadjuvant chemotherapy (NAC) alone for locally advanced rectal cancer (LARC) remains an experimental treatment, and the efficacy in terms of long-term outcome has not been fully elucidated. The N-SOG 03 trial examined the safety and efficacy of neoadjuvant CAPOX and bevacizumab (Bev) without radiotherapy in patients with poor-risk LARC. Methods Thirty-two patients with MRI-defined LARC received neoadjuvant CAPOX and Bev followed by curative resection between 2010 and 2011. The overall survival (OS), progression-free survival (PFS), and local-relapse rate (LRR) were calculated using the Kaplan-Meier method, and the risk factors were evaluated by multivariate analysis using the Cox proportional hazard models. This trial is registered with UMIN, number 000003507. Results In the entire cohort, the 5-year OS was 81.3%. Because of disease progression during chemotherapy, 3 patients ultimately did not undergo curative surgery. As a result, 29 patients underwent R0/1 resection. Among these 29 patients, the 5-year OS, PFS, and LRR were 89.7%, 72.4% and 13.9%, respectively. In multivariate analysis, cT4b tumor was an independent poor prognostic factor for OS and LRR, and ypT4b tumor and absence of N down-staging were independent poor prognostic factors for PFS. Conclusions Patients with cT4b tumor were not suitable for NAC alone. However, the long-term outcomes of the other patients were satisfactory, and NAC alone might be an option for treatment of LARC. N down-staging was likely to bring favorable PFS, even in patients with cStage III.