Preoperative long-course chemoradiotherapy plus adjuvant chemotherapy versus short-course radiotherapy without adjuvant chemotherapy both with delayed surgery for stage II-III resectable rectal cancer: 5-Year survival data of a randomized controlled trial

Abstract

Background and objective: At present, there are common recommendations for treatment for stage II-III resectable rectal cancer patients: preoperative conventional chemoradiotherapy (CRT) with delayed surgery in 6-8 weeks or preoperative short-course radiotherapy (SCRT) followed by immediate surgery. The aim of this study was to compare overall survival (OS) and disease-free survival (DFS) in two treatment groups: preoperative SCRT and CRT both with delayed surgery plus adjuvant chemotherapy in CRT arm.

Materials and methods: A total of 150 patients were randomly assigned to two groups: 75 to CRT (preoperative conventional CRT, 50Gy/25 fr with fluorouracil and leucovorin on the 1st and the 5th week of RT followed by TME surgery in 6-8 weeks and 4 cycles of adjuvant fluorouracil/leucovorin every 4 weeks; then follow-up) and 75 to SCRT (preoperative short-course RT, 25Gy/5 fr followed by TME surgery in 6-8 weeks; then follow-up). The data of 140 patients (72 in CRT and 68 in SCRT group) were included in statistical analysis. Primary end points were OS and DFS.

Results: Median follow-up was 60.5 (range, 5-108) months. The 5-year DFS was 67% in the CRT group (n=72) and 45% in the SCRT group (n=68) (P=0.013; HR=1.88; 95% CI, 1.13-3.12; P=0.015). The 5-year OS was 79% and 62% in the CRT and SCRT groups, respectively (P=0.015; HR=2.05; 95% CI, 1.13-3.70; P=0.017). The 5-year OS for intent-to-treat (ITT) population (n=150) was 78% in the CRT and 58% in the SCRT group (P=0.003; HR=2.28; 95% CI, 1.30-4.00; P=0.004).

Conclusions: The 5-year DFS and OS were significantly better in the CRT than the SCRT group. For ITT population, OS was also significantly better after CRT versus SCRT.

Keywords: Chemoradiotherapy; Radiotherapy; Rectal cancer.