CHEMORADIOTHERAPY VERSUS RADIOTHERAPY ALONE FOR ANAL CANCER - A RETROSPECTIVE COMPARISON

Purpose: To evaluate the effect of adding one cycle of concomitant che motherapy to curative radiotherapy on tumor control and toxicity in th e treatment of anal cancer. Methods and Materials: One hundred twenty- five patients completed curative sphincter-conserving treatment, 57 wi th radiotherapy alone and 68 with concomitant chemo-radiotherapy. Comp ared with chemoradiotherapy patients, radiotherapy patients were older (median age 71 vs 63) and had less advanced tumors (T3-4 26% vs 51%). Radiotherapy patients were usually treated with a direct perineal cob alt field (mean dose 31 Gy at 5 cm/10 fractions/3 weeks), complemented in most cases by a sacral arc field, followed (mean split 54 days) by Iridium-192 implantation (mean dose 23 Gy, Paris system). The large m ajority of chemoradiotherapy patients received antero-posterior oppose d 10 MV photon fields, including pelvic and inguinial nodes (mean dose 38 Gy/19 fractions/4 weeks), followed (mean split 42 days) by implant boost (mean dose 18 Gy). In addition, chemo-radiotherapy patients rec eived starting on day 1 an IV bolus of Mitomycin-C, 0.4 mg/kg (maximum 20 mg) and a 5-day continuous infusion of 5-fluorouracil 600-800 mg/m 2/day. Median follow-up was 65 months for radiotherapy and 48 months f or chemo-radiotherapy patients. Results: For all 125 patients at 5 yea rs, overall survival was 65.5%, definitive local control 83% and local control with sphincter preservation 68%. Overall and stage for stage, there was no difference in overall, progression-free or cancer-specif ic survival, nor in local control, local-regional control, or sphincte r preservation rates between patients treated with chemoradiotherapy v s. radiotherapy alone. There was no significant difference between the two groups regarding acute or late toxicity. Conclusion: This retrosp ective analysis does not confirm the efficacy of one course of simulta neous Mitomycin-C and 5-fluorouracil, at least in association with ful l-dose radiotherapy incorporating Iridium-192 boost.