Two-week course of preoperative chemoradiotherapy followed by delayed surgery for rectal cancer: A phase II multi-institutional clinical trial (KROG 11-02)

Purpose The aim of this study was to evaluate the efficacy and safety of a two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer. Methods and materials Eighty patients with rectal cancer located in the mid to low rectum, staged cT3-4N0-2M0, were prospectively enrolled they underwent preoperative chemoradiotherapy and delayed surgery 6-8 weeks after the completion of radiation therapy. A radiation dose of 33 Gy in 10 fractions was delivered to the pelvis for 2 weeks. One cycle of oral capecitabine was administered at a dose of 1650 mg/m²/day during radiotherapy. Tumor response and toxicity were the study endpoints. This study was registered at ClinicalTrials.gov (number, NCT01431599). Results All included patients underwent total mesorectal excisions including 12 cases of robot assisted surgery and 50 cases of laparoscopic surgery. Of the 80 patients, 27 (33.8%) achieved downstaging (ypT0-2N0) of a rectal tumor and 11 (13.8%) had a pathologically complete response (ypCR). Downstaging rates were 45% for T classification and 65% for N classification. Sphincter saving was achieved in 73 (91.3%) of the 80 patients. Of the 80 patients, 3 (3.8%) experienced grade 3 hematologic toxicity, and 2 (2.5%) had grade 3 postoperative complications such as ileus and wound dehiscence there was no grade 4 toxicity. Conclusion A two-week schedule of radiotherapy with oral capecitabine in locally advanced rectal cancer patients showed low toxicity profiles and promising results in terms of tumor response.