Therapeutic effects of oxaliplatin-based neoadjuvant chemotherapy and chemoradiotherapy in patients with locally advanced rectal cancer: a single-center, retrospective cohort study

Abstract

Background

Neoadjuvant chemoradiotherapy (NACRT) has now become the standard treatment for locally advanced rectal cancer (LARC). NACRT has decreased local relapse (LR) rate in patients with LARC; however, distant relapse has recently attracted much attention. This study aimed to assess the feasibility and efficiency of neoadjuvant chemotherapy (NAC) for LARC.

Methods

Data on patients with cT3/4 and N+ rectal cancer who were treated in our institution from April 2010 to February 2016 were reviewed retrospectively. Twenty-seven patients who received 2–9 cycles of oxaliplatin-based NAC and 28 patients who received NACRT (45 Gy delivered in 25 fractions and 5-fluorouracil-based oral chemotherapy) were analyzed. The primary and secondary endpoints of the present study were the 3-year relapse-free survival (RFS) and the local and distant relapse rates, respectively.

Results

Regardless of the kind of neoadjuvant therapy, no patient experienced any grade 3–4 therapy-related adverse events. The frequent toxic events were grade 1 diarrhea in patients with NACRT and neutropenia in patients with NAC. A significantly higher proportion of patients with NAC underwent laparoscopic surgery and anterior resection (p = 0.037 and p = 0.003, respectively). The percentages of patients with lymph node yield less than 12 in the NAC group, and those in the NACRT group were 26 and 68%, respectively (p = 0.002). Comparing the NAC with the NACRT groups, the local relapse and distant relapse rates were 7.4 and 7.1% and 7.4 and 18%, respectively. There were no significant differences in 3-year RFS and 4-year overall survival (OS) between NAC and NACRT (3-year RFS 85.2 vs. 70.4%, p = 0.279; 4-year OS 96.3 vs. 89.1%, p = 0.145, respectively). With an analysis excluding patients who received postoperative adjuvant chemotherapy, no patients who received NAC had a distant relapse, and there was a significant difference in 3-year RFS compared with the NACRT groups (94.4 vs. 63.2%, p = 0.043).

Conclusion

These outcomes suggest that the therapeutic effect of oxaliplatin-based NAC is at least equal to that of NACRT and that NAC is a feasible and promising option for LARC.