Epidermoid carcinoma of the anal canal treatment results and prognostic variables in a series of 242 cases.

UNLABELLED: From 1972 to 1985, 260 cases of anal canal epidermoid carcinoma were irradiated. Eighteen cases treated for palliation were excluded from the study; 242 (93%) were treated with curative intent. The sex ratio was 1/5.5; mean age was 66 years. HISTOLOGY: 60.3% were well differentiated epidermoid carcinoma; 31.0% moderately differentiated and 8.7%, cloacogenic cases. Staging: T1: 11.5%; T2: 16.1%; T3a: 17%; T3b: 33.5%; and T4: 21.9%. Abnormal inguinal nodes were present in 15.3% of cases. Crude overall survival (Kaplan-Meier) for the 242 cases is 86.4% at 1 year, 63.9% at 3 years, 51.2% at 5 years, and 30.8% at 10 years. Radiation therapy was the sole treatment for 193 cases. No chemotherapy was given. Patients were irradiated by external beam. They received a first course of X rays (mostly 18 MV, some 6 MV) 40 to 45 Gy (box technique) over 4 to 5 weeks in the pelvis. Age and size of tumor were considered when deciding on the target volume. After a rest period of 4 to 6 weeks, a second course of 15 to 20 Gy in 2 weeks was given through a perineal field by electron-beam of suitable energy. The mean total dose was 60.56 Gy and median was 62.5 Gy; the mean overall treatment duration was 85.3 days (median 82 days) and the mean Time Dose Factor including decay factor was 98.96. In this group, 5-year determinate survival was: T1-T2, 84.5%; T3a, 74.8%; T3b, 64.9%; T4, 58.9%. In 147/193 patients (76.2%) local control was achieved. The overall anal conservation rate was 62.6%. In 106 cases (55%), the anus had maintained normal function. The 5-year survival rate by N was 73.3% in the absence of inguinal nodes (169 cases) and 36.1% if such nodes were present. There was no significant difference in survival rate according to histological type. In the second group, receiving radiation therapy plus surgery, 33/49 cases (T3b-T4) were irradiated before surgery (median dose 40.5 Gy). Post operative radiation therapy was administered in 16 cases (T3b-T4) (median dose 49.6 Gy). The 5-year determinate survival is 53.2% for T3b and 79% for T4. According to the log-rank test, there was no significant difference between survival with radiation therapy alone and radiation therapy plus surgery. Multivariate analysis of the whole group indicated that T stage is the only predictive variable.(ABSTRACT TRUNCATED AT 400 WORDS)