INCOMPLETELY RESECTED RECTUM, RECTOSIGMOID, OR SIGMOID CARCINOMA - RESULTS OF POSTOPERATIVE RADIOTHERAPY AND PROGNOSTIC FACTORS

Postoperative radiotherapy was given in 40 patients with gross or microscopic pathologically proven residual disease after surgical resection of rectum, recto-sigmoid, or sigmoid carcinoma. The radiotherapy target volume included the pelvis with (9 patients) or without (31 patients) the perineum. Median total dose of radiation was 50 Gy (range 30 - 60). One patient received 30 Gy, 10 received > 30 to 40 Gy, 13 received > 40 to 50 Gy, and 16 patients received > 50 to 60 Gy. The median follow-up in the survivors (16 patients) was 53 months (range: 16-85). Probability of survival with censoring for death due to intercurrent disease was 36% at 5 years. Survival for patients with microscopic residual disease (21 patients) was 40% at 5 years compared to 12% for those with gross residual disease (19 patients) (p = 0.09). Twenty-five patients relapsed. All but one relapse occurred earlier than 50 months after radiotherapy. Approximately half (12/25) of the relapses were observed within 6 months after radiotherapy. Local relapse inside the radiotherapy portals was observed in 9/40 (22%) patients. Therapy-related urogenital complications occurred in no patient and gastro-intestinal complications in three patients (7%). In one patient they were scored WHO grade 4 and in two patients WHO grade 3. Prognostic factors were analyzed using the Cox proportional hazards model. For survival differentiation, grade (p < 0.001), stage (p = 0.04), and perineal irradiation (p = 0.03) were independent prognostic factors. With relapse-free survival as the endpoint, only stage (p = 0.003) was a statistically significant prognostic factor. There was a trend toward a better relapse-free survival when the perineum was included in the radiation portals (p = 0.09).