Background

Concurrent chemoradiation for the treatment of anal cancer has been established to result in long term disease free survival and sphincter preservation in a majority of patients. Conformal radiotherapy delivered using ACT2 protocol reports 61% grade3/4 non-haematological toxicity (James et al ASCO 2010). This is a retrospective analysis of patients treated with IMRT delivered using ACT2 schedule at the Royal Marsden Hospital Sutton evaluating the toxicity profile and response rates.

Method

24 patients were treated with IMRT and concurrent chemotherapy (MMC 12mg/m² and daily capecitabine 1250mg/m²) between November 2010 and May 2012. 30.6 Gy over 17 fractions to the pelvis was delivered as aninverse planned5 field IMRT for phase 1 treatment with an additional 19.8Gy over 11 fractions given as a conformally planned phase 2 boost to the tumour and any involved nodes. Toxicities were graded according to the CTC AE version 4.0.

Results

Median age of patients was 56 (range 40-84) years with a majority being females (70.8%). Two were HIV positive. Three patients had a defunctioning procedure prior to treatment. 7(29.1%) patients were either T3/T4 or N1/2. Only one required radiotherapy treatment interruption and 3 (12.5%) needed admission for symptom control. All patients completed prescribed radiotherapy. Chemotherapy breaks were necessary in 7(21.9%) patients.14 (58.3%) and 6 (25%) patients experienced G2 and G3 acute skin toxicity respectively. 5(20.8%) and 4(16.7%) of patients experienced G2 and G3 acute GI toxicities. GU toxicity was minimal. 2 patients had grade3 neutropenia. Response at 3 months was evaluable for 19 patients with 84.2% having a complete response clinically and radiologically.

Conclusion

IMRT with concurrent chemotherapy appears well tolerated and effective in the management of anal cancer. The lack of haematological toxicity could be explained by low superior field border therefore sparing bone marrow.