Chemoradiotherapy versus radiotherapy alone for anal cancer: a retrospective comparison

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.

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.

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.

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.