The Role of Adjuvant Postoperative Radiotherapy in Curative Resectable Sigmoid Colon Carcinoma / 대한치료방사선과학회지

ABSTRACT

PURPOSE: To evaluate the role of postoperative radiation therapy after curative resection of sigmoid colon cancer MATERIALS AND METHODS: From 1988 to 1993, a total of 93 patients with curative resectable sigmoid colon cancer of modified Astler-Coller (MAC) stage B2, B3, C2, C3 was divided into two groups on the basis of those who received radiation treatment and those who did not. Forty-three patients who treated by surgery alone were classified as postop RT ( group. The remaining 50 patients who underwent postoperative radiotherapy were classified as postop RT (+) group. In all patients in postop RT (+) group, radiation therapy was delivered using 4 or 10 MV linear accelerators to treat the tumor bed with approximately 5cm margin to a total dose 50.4-61Gy (median 54Gy) in 1.8Gy per fraction. Thirty-two patients were treated with 5- Fluorouracil based adjuvant chemotherapy at least 3 cycles, but these was no significant difference between two groups. Treatment failure pattern, 5-year local failure-free survival rates (LFFS), and 5-year disease-free survival rates (DFS) were compared between two groups. RESULTS: Five year LFFS and DFS were 85.1%, 68.5%, respectively. In postop RT (-) group, LFFS was 76.2%, compared with 91.7% in postop RT (+) group. Improved LFFS and DFS were seen for patients with stage C3 sigmoid colon carcinoma with postoperative radiation therapy compared with postop RT (-) group (P=0.01, P=0.06 respectively). In stage B3, LFFS washigher in postop RT (+) group than that in postop RT (-) group, although it was not significant. Especially, local control was higher in stage T4 in postop RT (+) group than that in postop RT (-) group. CONCLUSION: This study showed significantly improved LFFS and DFS in MAC Stage C3 and improved tendency of LFFS and DFS in MAC Stage B3 disease. Large scale prospective study is required to verify the role of adjuvant radiation therapy in resectable sigmoid colon cancer.