Randomized Trial of Postoperative Adjuvant Therapy in Stage II and III Rectal Cancer to Define the Optimal Sequence of Chemotherapy and Radiotherapy: 10-Year Follow-Up

Abstract

To determine the optimal sequence of postoperative adjuvant chemotherapy and radiotherapy in patients with Stage II or III rectal cancer. A total of 308 patients were randomized to early (n = 155) or late (n = 153) radiotherapy (RT). Treatment included eight cycles of chemotherapy, consisting of fluorouracil 375 mg/m(2)/day and leucovorin 20 mg/m(2)/day, at 4-week intervals, and pelvic radiotherapy of 45 Gy in 25 fractions. Radiotherapy started on Day 1 of the first chemotherapy cycle in the early RT arm and on Day 1 of the third chemotherapy cycle in the late RT arm. At a median follow-up of 121 months for surviving patients, disease-free survival (DFS) at 10 years was not statistically significantly different between the early and late RT arms (71% vs. 63%; p = 0.162). A total of 36 patients (26.7%) in the early RT arm and 49 (35.3%) in the late RT arm experienced recurrence (p = 0.151). Overall survival did not differ significantly between the two treatment groups. However, in patients who underwent abdominoperineal resection, the DFS rate at 10 years was significantly greater in the early RT arm than in the late RT arm (63% vs. 40%; p = 0.043). After the long-term follow-up duration, this study failed to show a statistically significant DFS advantage for early radiotherapy with concurrent chemotherapy after resection of Stage II and III rectal cancer. Our results, however, suggest that if neoadjuvant chemoradiation is not given before surgery, then early postoperative chemoradiation should be considered for patients requiring an abdominoperineal resection.