Phase II study of capecitabine (Xeloda®) and concomitant boost radiotherapy in patients with locally advanced rectal cancer

Purpose: The aim of this study was to determine the efficacy of capecitabine (Xeloda®), an oral fluoropyrimidine, as a radiosensitizer in the neoadjuvant treatment of locally advanced rectal cancer (LARC). Methods and Materials: We conducted a phase II study of capecitabine (825 mg/m² orally, twice daily continuous) with radiotherapy (52.5 Gy/30 fractions to the primary tumor and perirectal nodes) in 54 patients with LARC (node-negative ≥T3 or any node-positive tumor) staged by endoscopic ultrasound (EUS). The primary endpoint was pathologic response rate; secondary endpoints included toxicity profiles and survival parameters. Results: Of the 54 patients (median age, 56.7 years; range, 21.3-78.7 years; male:female ratio, 1.7; Eastern Cooperative Oncology Group performance status 0-1: 100%), 51 patients (94%) had T3N0 or T3N1 disease by EUS. Surgery was not performed in 3 patients; 2 of these patients had metastatic disease, and the third patient refused after a complete clinical response. Of the 51 patients evaluable for pathologic response, 9 patients (18%) achieved complete response, and 12 patients (24%) had microscopic residual disease (<10% viable cells). In addition, 26 patients of all 54 patients (51%) achieved T-downstaging, and 15 patients of 29 patients (52%) achieved N-downstaging. Grade 3/4 toxicities were radiation dermatitis (9%) and diarrhea (2%). Sphincter preservation rate for tumor ≤5 cm from the anal verge was 67% (18/27). Conclusion: This regimen of radiotherapy plus capecitabine is well tolerated and is more convenient than protracted venous infusion of 5-FU. The pathologic response rate is comparable to our previous experience using protracted venous infusion 5-FU for LARC.