Purpose: To evaluate the effect of adding one cycle of concomitant chemotherapy to curative radiotherapy on tumor control and toxicity in the treatment of anal cancer.
Methods and materials: One hundred twenty-five patients completed curative sphincter-conserving treatment, 57 with radiotherapy alone and 68 with concomitant chemo-radiotherapy. Compared 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 cobalt field (mean dose 31 Gy at 5 cm/10 fractions/3 weeks), complemented in most cases by a sacral are field, followed (mean split 54 days) by Iridium-192 implantation (mean dose 23 Gy, Paris system). The large majority of chemoradiotherapy patients received antero-posterior opposed 10 MV photon fields, including pelvic and inguinal 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 received 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/m2/day. Median follow-up was 65 months for radiotherapy and 48 months for chemo-radiotherapy patients.
Results: For all 125 patients at 5 years, 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-specific survival, nor in local control, local-regional control, or sphincter preservation rates between patients treated with chemoradiotherapy vs. radiotherapy alone. There was no significant difference between the two groups regarding acute or late toxicity.
Conclusion: This retrospective analysis does not confirm the efficacy of one course of simultaneous Mitomycin-C and 5-fluorouracil, at least in association with full-dose radiotherapy incorporating Iridium-192 boost.