Acute toxicity of breast cancer irradiation with modulated intensity by tomotherapy

Helical radiation intensity modulated by tomotherapy improves dose distribution to complex and large volumes. The aim of the study was to assess acute toxicity of this technique during breast cancer irradiation after conserving surgery or mastectomy. Cutaneous toxicities, lung and oesophageal side effects, and breast lymphedema were retrospectively collected according to the Common Terminology Criteria for Adverse Events Version 4.0 (CTCAE v4.0) in 292 patients treated for a breast cancer by tomotherapy between May 2010 and December 2014. After conservative surgery, the dose administered to breast volume and the tumour bed was respectively 52.2Gy and 63.8Gy in 29 fractions. After mastectomy, the dose was 50Gy in 25 fractions. Univariate and multivariate analyses were performed to highlight risk factors for dermatitis and breast oedema. The rate of dermatitis grade 2 and 3 were 22.9% and 1.7% respectively. In univariate analysis, factors associated with acute radiation dermatitis were breast volume (P=0.002), body mass index (BMI) (P