Randomized trial of postoperative adjuvant therapy in stage II and III rectal cancer to define the optimal sequence of chemotherapy and radiotherapy: a preliminary report.

Abstract

We conducted a prospective randomized trial to define the optimal sequence of chemotherapy and radiotherapy of postoperative adjuvant treatment in stage II and III rectal cancer. Three hundred eight patients were enrolled onto the study. We randomly assigned 155 to arm I (early radiotherapy group) and 153 to arm II (late radiotherapy group). Treatment included eight cycles of chemotherapy at 4-week intervals and pelvic radiotherapy of 45 Gy in 25 fractions. Radiotherapy started on day 1 of the first chemotherapy cycle in arm I and on day 1 of the third chemotherapy cycle in arm II. The chemotherapy regimen consisted of fluorouracil 375 mg/m(2)/d and leucovorin 20 mg/m(2)/d. Chemotherapy was administered for 3 days per cycle in two cycles during the period of radiotherapy and for 5 days per cycle in the remaining six cycles. Twenty patients in arm I and 14 in arm II were not eligible. We included 274 patients in the analysis. With a median follow-up of 37 months for surviving patients, disease-free survival was significantly prolonged in arm I compared with arm II (81% v. 70% at 4 years; P =.043). Twenty-three recurrences occurred in arm I and 38 in arm II (P =.047). Overall survival was not significantly different between arms I and II (84% v. 82% at 4 years; P =.387). Early radiotherapy with concurrent chemotherapy after resection of stage II and III rectal cancer demonstrated a statistically significant advantage for disease-free survival compared with late radiotherapy with chemotherapy.