Effect of adjuvant radiotherapy on local recurrence in stage II rectal cancer

Background: Prospective trials have demonstrated that chemotherapy combined with radiotherapy decreases local recurrence rates in stage II and stage III rectal cancer. Some patients with stage II lesions, however, have relatively low risks of local recurrence. We evaluated the effect of radiotherapy on local recurrence in patients with stage IIA rectal cancer. Methods: From the colorectal cancer database, we identified 390 stage IIA rectal cancer patients who underwent curative resection followed by adjuvant therapy from 1995 to 2002; a total of 72 patients who received preoperative chemoradiotherapy and who did not receive adjuvant therapy were excluded. Mean follow-up period was 65 months (range, 2-133 months). Results: Of the 390 patients, 110 had primary tumors in the upper rectum, 136 in the midrectum, and 144 in the lower rectum. Lymphovascular invasion was observed in 35 patients (9.0%). Mean (+/- SD) number of examined lymph nodes was 18 (+/- 12). Adjuvant chemotherapy was provided to 180 patients (46.2%), and chemotherapy plus radiotherapy was provided to 210 patients (53.8%). Radiotherapy was significantly more common in younger patients (P = .01) and those with lower rectal cancer (P < .001). Local recurrence rate did not differ between patients who did and did not receive radiotherapy. In patients with mid and lower rectal cancer, the local recurrence rate was not affected by radiotherapy. Conclusions: Radiotherapy did not seem to provide additional benefit in decreasing local recurrence rate of stage IIA rectal cancers. In selected patients, however, the role of radiotherapy needs to be carefully evaluated.