Background: Currently surgery is reserved as salvage treatment of anal carcinomas (AC) resistant to radiotherapy (RT) or chemoradiation (CRT). The prediction of initial treatment failure of AC is an important issue. The aim of this prospective study was to define clinical and therapeutic factors associated with poor response of AC and to evaluate the role of surgery as salvage option.
PATIENTS: Between 1995-2005, 108(98 female) patients [mean age 61(33-81)] with AC were included into prospective study. There were 61(56.5%) T1-2N0M0 and 12(11.1%) T1-2N1-2M0; 17(15.7%) T3-4N0M0 and 18(16.7%)T3-4N1-3M0. Of 108 AC 71(65.7%) were presented with keratinized squamous-cell carcinomas and the rest AC were non-keratinized or basaloid.
ENDORECTAL ULTRASONIC STAGING: EUS staging was performed using the linear 7.5MHz transduser. We based our uTNM system on the tumor invasion into surrounding tissues. There were no tumors confined by subendothelial layer of anal canal (uT1). 33 (30.6%) tumors were confined by the internal anal sphincter (uT2); 24(22.2%) invaded to the external anal sphincter (uT3) and 51(47.2%) invaded into levator ani muscle or perirectal fat (uT4) or to surrounding organs e.g. vagina. All clinical T4 carcinomas (n=14) corresponded to uT4.
INITIAL TREATMENT REGIMES: Of 108 patients 58 had RT (split-course 60-65Gy), 19 had hyper-fractionated RT (1.5Gy - 1st session and 1.0Gy -2nd session combined with 5-FU up to 55-65Gy); 20 had CRT (60-65Gy, 5-FU and mitomycin C) and 11 had RT combined with capecitabin.
Results: The overall complete regression rate was 66/108(61.1%) with overall 5-year survival of 81.7% in good responders. No therapeutic factors (CRT or RT, boost type, overall treatment time) as well as age, sex, nodal status were related to AC response, while T stage, tumor invasion (uT) and keratinized type of AC were significant in univariate analysis. Complete response (CR) of AC was obtained in 53/73(72.6%) of T1-2 and in 13/35(37.1%) of T3-4 (p=0.005). CR of AC was achieved in 27/33(81.8%) of uT2, 17/24(70,8%) of uT3 and 22/51(37.3%) of uT4 (p=0.0005). Keratinized AC responded poorer to RT/CRT 37/71(52.1%) comparing to non-keratinized or basaloid AC 29/37(78.3%)(p=0.01). In multivariate logistic analysis only uT was independent prognostic variable (p=0.015). Of 42 residual AC abdomino-perineal excision (APE) was used in 35 cases with 5-year survival rate of 69.0%.
Conclusion: The predictive value of EUS uTNM staging based on AC invasion was demonstrated in presented study. APE remains the salvage modality of choice for residual AC.