Epidermoid carcinomas of the anal canal treated with definitive radiation therapy in a series of 305 patients

Abstract

To identify prognostic factors and treatment toxicity in a serie of epidermoid cancers of the anal canal without evident metastasis. Between June 1972 and January 1997, 305 patients (pts) were treated with curative-intent radiation therapy (RT). The T-stages according to the 1987 UICC classification were: 26 T1, 141 T2, 104 T3, and 34 T4. There were 49 pts with nodal involvement at presentation. Pretreatment anal function scoring according to our in-house system was: 22 scored 0, 182 scored 1, 74 scored 2, 7 scored 3, 11 scored 4, and 9 not available pts. The treatment started with external beam RT (EBRT) in 303 pts (median dose: 45 Gy). After a rest period of 4 to 6 weeks, a boost of 20 Gy was delivered by EBRT in 279 pts and by interstitial 192Ir brachytherapy (Bcy) in 17 pts. Seven pts received only one course of EBRT (mean dose: 49.5 Gy) and 2 pts were treated with interstitial 192Ir Bcy alone (55 and 60 Gy, respectively). Concomitant chemotherapy (5-fluoro-uracil and either mitomycin C or cisplatin) was delivered to 19 pts. Mean follow-up was 103 months. At the end of RT local tumor clinical complete response (cCR) rate was 80%. Out of 61 non responders or local progressive tumors 27 (44%) were salvaged with abdominoperineal resection (APR). The rate of local tumor relapse (LR) was 12%. Out of 37 LTR, 20 (54%) were salvaged with APR and one with interstitial 192Ir Bcy. The orevall local tumor control (LC) rate with or without salvage local treatment was 84%. LC rate with a good anal function scoring (score 0 and 1) was 56.5%. Among 181/186 available pts who preserved their anus, 94% had a good anal function scoring. For a subgroup of 15 pts with length tumor <2 cm-N0, the LC rate after the end of RT was 100%, the LC rate with or without local salvage treatment was 100%, and among 13 available pts who preserved their anus, the anal function scoring was good in 12 pts (92%). The 10-years disease-free survival was 74%. After multivariate analysis, 3 independent predicting factors significantly influenced the disease-free survival: gap duration between 2 courses of RT (>38 days vs < or =38 days, P =0.0025), pretreatment anal function scoring (0 vs 1 vs 2 vs 3 vs 4, P =4.4 10(-6)), and cCR after the end of RT (no complete response vs complete response, P =2.5 10(-14)). We confirm excellent results with RT in T1 and T2 lesions. However, chemoradiotherapy should be prefered to improve survival free of colostomy with a good anal sphincter function for tumors more than or equal to 2 cm in length and locally advanced tumors.