Stepwise multicenter introduction of intensity modulated radiation therapy for anal cancer in the United Kingdom: from consensus guidance to large-scale prospective audit, prior to future clinical trials

Purpose/Objective(s) The ACT 2 trial determined the standard UK radiotherapy technique in chemoradiotherapy for anal cancer. Intensity-modulated radiotherapy (IMRT) is increasingly used due to reduced acute toxicity, however the implementation in a multicenter setting is challenging. We planned a stepwise implementation of IMRT prior to the PLATO study; an anal cancer trial due to open in 2016, investigating optimization of radiotherapy dose. We developed a consensus guidance document, adapting the ACT 2 doses and volumes for IMRT, and this was presented and published in 2014 [1]. We then performed an audit of clinical practice prior to the opening of the PLATO trial. Materials/Methods The Royal College of Radiologists carried out a prospective national audit, over a 6-month period between February and July 2015. All UK cancer centers were asked to submit details of consecutive anal cancer patients receiving radiotherapy over that period. Results Two hundred and forty-two cases were received from 41 centers. Median age was 62 (range = 29 to 90), with a female to male ratio of 2.8. 99% had invasive squamous cell, basaloid, or cacogenic carcinoma. T1/2 and T3/4 constituted 53.5% and 46.7% of tumors respectively. 49.6% had positive lymph nodes. 64.5% and 28.1% underwent Mitomycin / 5FU and Mitomycin / Capecitabine respectively. Initial analysis reveals 187 (77.3%) received treatment using inverse planning of which 148 patients received full dose radiotherapy using the doses and delivery proposed in the guidance. For toxicity comparisons the grade 3 + 4 toxicity in 3 groups were compared; those treated as per consensus guidance, those treated using the ACT 2 protocol within the audit and the published toxicity from the ACT 2 trial. Toxicity was as follows: Non-hematological - 40%, 49%, and 62%; hematological - 17%, 13%, and 26%; skin - 26%, 43%, 48%; and pain - 12%, 17%, 26%. Diarrhea was reported in 12%, 2%, and 9%. Further analysis demonstrated this was different in c