Clinical Trial of The Use of Bolus in Post Mastectomy Irradiation in Breast Cancer

The aim of this study is to evaluate the impact of adding bolus in adjuvant radiotherapy after mastectomy, in relation to the time of treatment interruption and acute effects. This study evaluates whether there is an increase in treatment time with the addition of the bolus, which can overshadow the benefit of increased dose to the skin and subcutaneous tissue. The patients will continue to be followed for oncologic outcomes, focusing on chest wall local control.

Rational: * The use of high-energy photons (6 MeV) creates a characteristic skin-sparing effect, which can generate a region of low-dose subcutaneous tissue. * The subcutaneous tissue is a possible area of clinical failure in the chest wall after mastectomy for breast cancer. * To optimize treatment, it is used a bio-equivalent material to increase the surface dose. * This dose increase may be accompanied by greater skin reaction, making it necessary to temporarily discontinue treatment to recover radiodermatitis. * The total treatment time is a determinant of tumor control in the treatment of cancer with radiation. Description: * This study aims to evaluate whether different intensities of application of the bolus correlate with greater likelihood of treatment discontinuation. * This will be a single blind randomised controlled trial. The target population comprises patients with indication of post mastectomy radiation (PMRT). * The patients will be divided into two groups: one with higher risk of recurrence in subcutaneous, which will be randomized to use 0.5cm bolus every other day or on consecutive days, and one lower risk group, which will be randomized to use bolus 0.5cm on alternate days or do not use bolus. The group with high risk is defined as patients with clinical or pathological tumor invasion of skin. The others will be considered standard risk. * Randomization will be made so that each group has the same proportion of patients with high body mass index (\> / = 30 kg/m2), as this may be a factor in worsening radiodermatitis. * The patients will be followed during treatment and will be evaluated weekly for the radiodermatitis, interruption time of treatment for recovery from the acute effects and expenditures for local care. The evaluation will be done blindly (without knowledge of the utilization of bolus) by trained nurses in the management of radiodermatitis. After treatment, patients will continue to be followed for oncologic outcomes, focusing on chest wall local control.