Abstract

A phase II trial was done to evaluate the efficacy and safety of a postoperative radiation therapy and chemotherapy in patients who had undergone "curative" surgical resection for rectal adenocarcinoma. Eighty-six rectal cancer patients with pathologic stsge of Astler-Coller B1 and C were entered into this study between January 1986 to January l990. Four patients were excluded from the analysis because they were lost to fo11ow-up. Radiation therapy was begun 3-4 weeks after surgery. A total dose of 5,000 to 6,000 G was delivered in a period of 5 to 6 weeks. 5-fluorouracil(5-FU) was administered intravenously in a dose of 500 mg per square meter on the first three days of radiation as a radiosensitizer. Four weeks after radiation therapy was completed, 5-FU maintenance chemotherapy was started. 5-FU, 12mg/kg/day, was given intravenously in a bolus on days I-5 of a treatment cycle. Each chemotherapy cycle was repeated every 4 weeks upto twelve cycles or until evidence of treatment failure was documented. At the time of analysis(Aug. l994), 46 of the 82 patients(56%) had recurrence of their cancer. Of the 46 patients in whom recurrent diseases developed, 13 had locoreaional recurrences and 29 had distant metastases as the first signs of recurrences. During the 4 to 84 months(median 45 months) of follow-up period, the median time to relapse-free survival, and overall survival were 31.3 months(4.2+ -83+ months) and 71.5 months(4.2+ -83+ months), respectively. The 5-year actuarial relapse-free survival, and overall survival rates of 82 patients were 40% and 64%, respectively. The prognostic value of several variables(age, sex, performance status, pathologic stage, type of surgery, histologic subtypes, preoperative CEA level, and number of cycles of maintenance chemotherapy) was assessed. Among them, type of surgery, and number of cycles of maintenance chemotherapy(¡A6 vs. >7) were found to be significantly correlated with relapse-free interval, and age, preoperative CEA level, and number of cycles of maintenance chemotherapy were found to be significantly correlated with overall survival. The toxicities associated with radiation therapy and chemotherapy were mild and tolerable. There was no treatment-related mortality. In conclusion, the postoperative radiation therapy and 5-FU maintenance chemotherapy is effective and safe in patients with rectal cancer of Astler-Coller B2 and C stage.

• Keywords: Rectal cancer, Radiation therapy, Adjuvant Chemotherapy, 5-Fluorouracil