Fatores de risco para a ocorrência de radiodermatites e seu impacto na qualidade de vida de mulheres com câncer de mama submetidas à radioterapia: estudo coorte prospectivo

Abstract

Introduction: Among the most frequent acute adverse events in women with breast cancer (BC) in radiotherapy (RT) are the reactions in the skin denominated radiodermatitis. They are characterized by erythema, hyperpigmentation, peeling and ulceration that can cause pain, stress and impairment of quality of life (QoL). Objective: To evaluate the risk factors for the occurrence of radiodermatitis, the QoL of women with BC submitted to RT and the agreement between evaluators regarding the scales of radiodermatitis. Methods: A prospective cohort study was conducted to evaluate 100 BC women weekly and one to three months after the end of RT. Radiodermatitis were evaluated using the Radiation Therapy Oncology Group (RTOG) and World Health Organization (WHO) scales and QoL according to the Dermatology Life Quality Index (DLQI). The Kaplan-Meier survival analysis, the univariate and multivariate Cox model were applied to identify the risk factors for severe radiodermatitis (grade ≥2). Generalized Estimating Equations (GEE) were used according to the gamma model and the sequential Sidak test to identify the effect of treatment the evaluation times and degree of radiodermatitis on QoL. To evaluate the agreement between the evaluators that used the measurement scales, weighted Kappa and Krippendorf´s Alpha ordinal were calculated. The SPSS and R software’s were used. Results: According to the multivariate Cox model, the RT performed in the afternoon (HR = 1.566, p = 0.042), the separation of the tangential fields > 21 cm (HR = 2.923, p = 0.003), the moderate brown skin color (HR = 1.706, p = 0.022), dark brown (V) or black (VI) (HR = 5.336, p < 0.001) were associated with the early occurrence of severe radiodermatitis. Considering QoL, the total score and its domains "work and school", "leisure", "daily activities" and "symptoms and feelings" had an effect of RT time (p< 0.001), degree of radiodermatites (p≤ 0.002 ), and the interaction between the time of treatment and the degree of radiodermatitis (p < 0.001). When evaluating the post-hoc, higher mean values of the total QoL score were identified in the presence of radiodermatitis grade 3 (mean = 6.00) in T3, grade 4 in T5 (6.50) and T6 (7.00). Finally, a low and moderate agreement (RTOG: 0.409, 95% CI 0.369-0.438; WHO: 0.550, 95% CI 0.509-0.593) was observed among the evaluators who used these two measurement tools, in addition to general agreement of 10.2% and 28.8%, respectively. Conclusion: We suggest that women with BC presenting large breast and dark and dark brown color, should perform the RT in the morning (07-10) in order to reduce the early appearance of radiodermatitis and, consequently, clinically significant damage to their QoL. The RTOG and WHO scales should be used with caution in clinical practice since there was poor agreement among the evaluators.