Adjuvant versus neoadjuvant chemoradiotherapy in distal rectal cancer: Comparison of two decades in a single center

Standard surgery alone was not able to decrease local recurrence (LR) rate below 20% in rectal cancer treatment. Thus, many centers administered neoadjuvant radiotherapy (preopRTx) with or without concomitant chemotherapy for the prevention of LR. In this study, the results of 164 consecutive patients with mid- and distal rectal cancer who received surgery and adjuvant chemoradiotherapy (Group A) or neoadjuvant chemoradiotherapy (Group NA) followed by surgery are presented.

The staging system used in this study is that of the American Joint Committee on Cancer (AJCC), also known as the TNM system. Eligible patients were required to have radiologically assessed stage 1 (only T2N0M0) to stage 3C (T4bN1-2M0) tumor with pathologically confirmed R0 resection. The surgical method was total mesorectal excision (TME). Radiotherapy was applied with daily 180 cGy fractions for 28 consecutive days. Chemo-therapy comprised 5-fluorouracil (450 mg/m(2)/d) and leucovorin (20 mg/m(2)/d) bolus at days 1-5 and 29-33.

Nine patients (13%) in Group NA achieved pathologic complete response (pCR). In Group NA and Group A, locoregional recurrence (LRR) rates were 6.7% and 30.8%, (p<0.001), the mean LR-free survival was 190.0±7.3 months and 148.0±11.7 months (p=0.002) and the mean overall survival (OS) was 119.2±15.3 months and 103.0±9.4 months (p=0.23), respectively. A significant difference with regard to LR has been obtained with a statistical power of 0.92. Secondary outcome measures (DFS and OS) have not been met.

Neoadjuvant chemoradiotherapy with TME is an efficient treatment protocol, particularly for the treatment of magnetic resonance imaging-staged 2A to 3C patients with two or three distal rectal adenocarcinomas. Given that a considerable proportion of patients with cT2N0M0 would develop pCR, this method of treatment can be considered for further studies.