Preoperative chemoradiotherapy with oxaliplatin and tegafur-uracil in locally advanced rectal cancer: pathologic complete response rate and preliminary results of overall and disease-free survival in a single institute in Taiwan

Abstract

Background: We conducted a Phase II study of biweekly oxaliplatin plus oral tegafur-uracil in the preoperative chemoradiotherapy (CRT) for locally advanced resectable mid-to-lower rectal cancer in our hospital, to evaluate the feasibility of this drug combination in tumor pathologic response, acute toxicity, local control, disease-free survival (DFS), overall survival (OS), and time to distant metastasis in an Asian cohort.

Methods: Twenty patients with histopathologically confirmed rectal cancer (Stage II-III) were enrolled in the study. Radiotherapy of 50 Gy was delivered in 25 fractions of 2 Gy, one fraction/day, five fractions/week, for 5 weeks. Oxaliplatin 55 mg/m(2) was administered intravenously for 60 minutes on Day 1 every 2 weeks, and tegafur-uracil 350 mg/m(2) was given orally everyday during the whole radiotherapy course, including holidays. Surgery was scheduled 6 weeks after completion of the preoperative chemoradiotherapy. The primary endpoint was to determine the pathologic complete response (pCR) rate after this neoadjuvant chemoradiotherapy. The secondary endpoint was to determine the treatment-related toxicity profile, local control, DFS, OS, and time to metastasis.

Results: All patients underwent a complete course of preoperative chemoradiotherapy. There was no local recurrence during the study period. The complete resection rate was 20/20 (100%) and the close resection margin rate was 3/20 (15%). The pCR rate was 8/20 (40%). During chemoradiotherapy, the most frequent toxicity was diarrhea 9/20 (45% of patients, grade 2 in 3/20, 15%). There were no grade 3 or higher hematologic or non-hematologic events or treatment-related deaths. The 3-year OS and DFS rates were 94.1% and 78.6%, respectively.

Conclusion: Preoperative chemoradiotherapy with oxaliplatin and tegafur-uracil was well-tolerated and achieved an excellent pCR in our patients with locally advanced mid-to-lower rectal cancer.

Keywords: chemoradiotherapy; oxaliplatin; preoperative; rectal neoplasm; tegafur-uracil.