The Impact of Adjuvant Chemotherapy in Patients With Locally Advanced Rectal Cancer After Neoadjuvant Chemotherapy: A Propensity Score Matching Cohort Study.

Abstract

Background/aim: Total neoadjuvant therapy has been widespread over the past years and the multimodal treatment strategy involving administration of neoadjuvant chemotherapy (NAC) gradually increases for patients with locally advanced rectal cancer. However, the necessity of adjuvant chemotherapy (AC) following NAC remains controversial. The aim of this study was to investigate the impact of AC on survival outcomes and the influence of perioperative chemotherapy on treatment efficacy in patients with locally advanced rectal cancer (LARC) who received NAC followed by surgery.

Patients and methods: We retrospectively analyzed 107 patients with LARC who received NAC using propensity score matching (PSM) with covariates of clinical N stage, anus-preserving status, presence of severe complications (≥ Clavien-Dindo 3). All patients were planned and treated for three months with oxaliplatin-based doublet chemotherapy preoperatively.

Results: There were no significant differences between AC and Non-AC groups in 50 patients of the PSM cohort. At a median follow-up of 85.6 months, the 5-year overall survival was 88.0% and the 5-year relapse-free survival (RFS) was 81.3% for the entire cohort. The 5-year RFS was significantly better in the AC than in the non-AC group (87.3% vs. 79.8%, p=0.033). Multivariate analysis demonstrated that non-AC and lateral lymph node metastasis were poor prognostic factors of RFS in patients with LARC [non-AC: Hazard ratio (HR)=4.089, 95% confidence interval (CI)=1.217-13.735, p=0.023; lateral lymph node metastasis: HR=9.04, 95%CI=1.737-47.040, p=0.009].

Conclusion: AC could improve RFS in patients with LARC following NAC.