Effectiveness of preoperative chemoradiotherapy for advanced rectal cancer

To determine the pathologic effectiveness of preoperative chemoradiotherapy (CRT) in patients with advanced rectal carcinoma, we reviewed clinical records of 76 patients who received preoperative pelvic radiation +/- chemotherapy. Since 2 patients refused operation and 2 died before surgery, 72 patients underwent operation with a mean delay of 19.9 days after completion of irradiation. Pathologic tumor regression grade (Grade 0-3) was determined by the amount of viable tumor versus necrosis and fibrosis. Grade 0, 1 a, 1 b, 2, and 3 (pCR) were observed in 0%, 25.0%, 38.9%, 27.8% and 2.8% of patients, respectively. The pathologic response (PR) rate was 75.0% when PR was defined as greater than grade 1 b (tumor regression more than 1/3). Downstaging was observed in 35.8% of patients, in which 5-year overall survival was significantly better than in patients without downstaging (90.0% vs. 50.1%, p<0.05). No correlation could be observed between PR and downstaging. CRT is a useful tool with a high PR rate in patients with advanced rectal cancer. More accurate and careful clinical staging is important to select adequate candidates for CRT. Multi-institutional clinical trials as well as standardizing the surgical procedure including LN dissection are required to validate the advantages of CRT for Japanese patients.