RISK FACTORS FOR THE DEVELOPMENT OF RADIODERMATITIS IN WOMEN WITH BREAST CANCER: COHORT STUDY

Introduction: The radiotherapy has an important role in locoregional and distant control of the neoplasia, increasing the disease-free and overall survival rates. However, the radiodermatitis (RD) is an adverse effect with high incidence in this treatment. Objective: To evaluate the incidence of RD in women with breast cancer, identify the factors associated with its severity, and determine the time this side effect occurs during radiotherapy. Methods: This was a prospective and analytical cohort study which was carried out in the University Hospital. One hundred seventeen patients over 18 years old were included from February to September 2017. The patients were evaluated at the time of inclusion in the study and around every fifth application until the end of treatment. Chi-square or Fisher’s exact tests were used for categorical variables and T-Test for independent samples for parametric continuous variables and Kruskall-Wallis for non-parametric variables. For the assessment of risk factors, the logistic regression and the Cox proportional regression model was used. P values lower than 0.05 were considered significant. Results: The incidence rate of RD in breast area was 98.2% and it were demonstrated that for each additional point of Body Mass Index (BMI) the chance of occurrence of RD in grades II to IV increases by 14% [OR = 1.14 (CI95% 1.04 1.26); p=0.004] and the use of statin increases the risk of severe skin lesions by four times [OR = 4.27 (CI95% 1.11 16.42); p=0.035]. The exclusive use of hydrogel for skin hydration was an independent factor to delay the onset of RD when compared to patients using hydrogel associated with moisturising creams [HR = 0.55 (CI95% 0.36 0.82); p=0.004]. To the radiotherapy performed in the supraclavicular fossa, the incidence rate of RD was 97.5% and the hypothyroidism was an independent factor to decrease the free time of this side effect [HR=5.22 (1.09 24.90); p=0.04] while the exclusive use of hydrogel for skin hydration increases the free time of RD [HR= 0.38 (0.18 0.79); p=0.009]. Conclusions. These findings shows the high incidence of RD, associate BMI and use of statin with severe lesions and the use of hydrogel how an important factor to delay the emergency of this side effect.