Hypofractionated whole breast radiotherapy with or without hypofractionated boost in early stage breast cancer patients: a mono-institutional analysis of skin and subcutaneous toxicity

Abstract

Background: Our study evaluated skin and subcutaneous toxicity analyzing its correlation with patient- and treatment-related factors in a large mono-institutional series of women with early stage breast cancer treated with adjuvant hypofractionated whole breast radiotherapy (WBRT) with or without a sequential hypofractionated boost (HB).

Methods: Two hundred and nineteen patients, median age 62 years, received adjuvant hypofractionated WBRT in 16 fractions to a total dose of 42.4 Gy. Patients with negative prognostic factors received a HB of 2.65 Gy for 4 or 5 (patients with focal positive surgical margins) fractions. Systemic adjuvant treatments were hormonal therapy (HT) and/or chemotherapy (CHT) and/or Trastuzumab. Toxicities were assessed using the Common Terminology Criteria for Adverse Events (CTCAE 4.03) scale at 5th, 10th, 16th, 20th day from the start of radiotherapy (RT) and 1, 6 and 12 months after the end of RT. Univariate and multivariate analysis estimated toxicity predictive factors.

Results: No case of treatment interruption and no acute or late G3 toxicities occurred. In the univariate analysis HB administration resulted a risk factor for acute toxicity, while CHT administration and number of excised lymph nodes ≥ 10 resulted a risk factor for late toxicity. In the multivariate analysis none of the evaluated factors emerged a risk factor for acute and/or late toxicity.

Conclusions: Our results confirmed that hypofractionated WBRT even followed by a HB resulted safe and well tolerated. Longer follow-up is warranted to estimate late toxicity and treatment outcomes.

Keywords: Breast cancer; Hypofractionated whole breast radiotherapy; Hyprofractionated boost; Skin toxicity; Subcutaneous toxicity.