Stage I-III squamous cell cancers (SCC) of the anal canal are treated with definitive concurrent chemoradiotherapy. Capecitabine (Cape) and mitomycin-C (MMC) chemotherapy is an approved concurrent regimen, but with limited evidence.
A retrospective analysis of stage I-III SCC patients treated at Tata Memorial hospital with concurrent Cape-MMC (Capecitabine 1250mg/m2 PO continuous with IV Mitomycin C 12mg/m2 on D1) based chemoradiotherapy from March 2014 to March 2020 was conducted. Patients were staged as per American Joint Committee on Cancer, seventh edition. The primary outcome of the study was recurrence-free survival (RFS). Overall survival (OS) and RFS were calculated by Kaplan-Meier estimates.
Two hundred and twenty-six patients were included in the study, with the median age being 58 (range: 22-81) years. Stage I, stage II, and stage III cancers were seen in 1(0.4%), 62 (27.4%), and 163 (72.1%) patients, respectively. Patients received a median 45 Gy (range; 20-63) in 25 fractions as definitive radiotherapy with concurrent Cape-MMC. Response evaluation at 6 months was available in 190 patients, with 51 patients (27%) having local residual or progressive disease. Nine patients (4%) underwent salvage surgery. At a median follow up of 28 months, 38 recurrences had occurred, with 13 patients having only local recurrence while 25 patients had distant metastasis, with or without local recurrences. The median 2-year RFS was 82%, while median 2 years OS was 85%. Patients with stage III disease had inferior RFS as compared to patients with stage I/II disease (2 year RFS: 78% vs. 90%; p=0.042) Common grade 3 and grade 4 toxicities were local skin reactions in 44 (21.4%), neutropenia and thrombocytopenia in 9 (4.4%) patients, respectively.
The current study using chemoradiation with Cape-MMC is a large study in predominantly stage III anal canal cancers and shows excellent loco-regional control rates and tolerance in comparison to the traditional 5 fluorouracil-based regimens.
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