83 patients had radiotherapy for anal cancer, with 76 included in the analysis. Patients excluded had non-IMRT or palliative treatment. 66% of patients were female. Median age was 62 years (range 28-90 years).
The percentages of patients with T1, T2, T3 and T4 disease were 21%, 30%, 29% and 19% respectively. The percentages of patients with N0, N1, N2 and N3 disease were 44%, 22%, 16% and 17% respectively. Most patients had moderately differentiated histological grade (64%). Seven patients had basaloid subtype.
The radiotherapy treatment schedule was 50.4 Gy in 28 fractions to involved regions. 40 patients (53%) with higher stage disease had simultaneous integrated boost to primary to 53.2 Gy in 28 fractions. 4% of patients received 41.4 Gy in 23 fractions as part of the PLATO clinical trial for low-risk disease.
13% of patients had a defunctioning stoma prior to radiotherapy. 80% of patients received concurrent mitomycin C and capecitabine. Capecitabine alone (3%) or mitomycin C/5-FU (1%) were used infrequently. 16% of patients did not have chemotherapy. 8% started on a reduced dose of chemotherapy due to co-morbidities, and 11% had reduced dose intensity during treatment. Reasons for chemotherapy interruption included thrombocytopaenia, renal impairment and skin toxicity. There was no Grade 4 toxicity.
Median follow-up was 16 months (range 1-61 months). Nine patients (12%) had local recurrence. Seven of these patients had T3/4 disease or nodal involvement. Three did not receive chemotherapy during treatment. Five patients with local recurrence were successfully treated with salvage surgery, while the others declined or were not fit for surgery. The rate of metastatic progression was 13%, and all these patients had T3/4 disease or nodal involvement at presentation. For the whole cohort, 12-month overall survival was 88% and 24-month overall survival was 84%.