This study aimed to evaluate whether earlier initiation (< 4 weeks) of adjuvant chemotherapy (ACT) confer any oncological benefits for locally advanced rectal cancer (LARC) patients undergoing neoadjuvant chemoradiotherapy (nCRT) and radical surgery.
Clinicopathological and survival outcomes were compared. Propensity score matching (PSM) was performed to adjust for differences between groups. Cox regression analysis was performed to evaluate the impact of earlier ACT initiation on overall survival (OS) and disease-free survival (DFS).
Totally, 443 eligible patients were included. More laparoscopic surgeries, less postoperative complications, and more ACT completion were observed in patients whose ACT was initiated within 4 weeks after surgery (all P < 0.001). With a mean follow-up of 59 months, the 5-year OS and DFS rate was 89.8% and 82.0% in the early group, significantly higher than 81.6% and 73.1% in the late group (P = 0.007, and P = 0.022, respectively). After PSM, the 5-year OS and DFS rate was 90.9% and 84.4% in the early group, significantly higher than 83.4% and 68.8% in the late group (P = 0.047, and P = 0.017, respectively). Cox regression analysis demonstrated that time to ACT initiation (early vs. late, HR = 0.486, P = 0.008) was independently associated with OS.
Early initiation of ACT (<4 weeks) confers a survival benefit, and is an independent prognostic factor of OS in LARC patients following nCRT. Further investigations are needed to define the role of earlier initiation of ACT in patients with LARC after nCRT.