Study of Maximal Respiratory Pressures after Exposure to Breast Radiotherapy in Women: a Pilot Study

Abstract

Introduction: Postoperative radiotherapy is widely used to reduce risks of locoregional recurrence of breast cancer. However, the radiation of the thoracic structures involves risks, especially to the lungs. Objective: To study the Maximal Respiratory Pressures (MRP) after exposure to breast radiotherapy (RT) in women. Method: Prospective observational study conducted at the Alfredo Abrão Cancer Hospital in Campo Grande, state of Mato Grosso do Sul - MS. The study sample consisted of women (N = 08) exposed to breast RT after quadrantectomy surgery. Respiratory muscle strength was assessed through Maximal Inspiratory Pressure (MIP) and Maximal Expiratory Pressure (MEP) using a portable device called manovacuometer. The exam was performed before the 1^st session of RT and after the 25^th session corresponding to the last day of radiotherapy treatment. It were also evaluated the weight and height to measure the body mass index (BMI), clinical respiratory symptoms of dyspnea using the Medical Research Council (MRC) Dyspnea Scale and characterization of cough with the Common Lung Toxicity Criteria according to the clinical pneumonitis classification. Results: MIP values were 95.90±23.86 and 81.20 ±23.12 (mean ±standard deviation p = 0.035) in relation to the ideal percentage, characterizing a significant decrease when comparing before and after RT exposure. It was observed level of significance of p<0.05, t-student and paired test were applied. Conclusion: The study of MRP before and after exposure to breast RT showed a significant decrease in MIP.