Impacto da intervenção nutricional e composição corporal sobre eventos adversos do tratamento em mulheres diagnosticadas com câncer de mama

Abstract

Breast cancer is the most common oncological diagnosis among women worldwide. Its treatment often involves multimodal approaches, such as surgery, chemotherapy (CT), radiotherapy and hormonal therapies. Although these treatments have significantly improved survival rates, they are also associated with a series of adverse effects that negatively affect the anthropometric nutritional status and body composition of patients, causing undesirable adverse effects. Although there are different studies on this topic, the evaluation of nutritional interventions on adverse events during neoadjuvant chemotherapy treatment in young women (<40 years) with breast cancer is still little explored. In addition, the relationship between changes in body composition and mortality in this age group is still unknown. This doctoral thesis aimed to evaluate the effect of nutritional intervention on adverse events (CT and radiotherapy toxicity, post-surgical complications, gastrointestinal symptoms) and the impact of body composition on the prognosis of mortality in women diagnosed with breast cancer. The thesis is composed of products from two studies: 1) the first study was a randomized clinical trial conducted at the beginning of neoadjuvant chemotherapy (NACT) including women with breast cancer treated at a reference center in oncology in Brazil and followed until the end of the radiotherapy period, at least. This study aimed to evaluate the effect of early nutritional intervention on adverse clinical events in women with breast cancer undergoing NACT; 2) the second study was a cohort study with retrospective data collection, which aimed to investigate the relationship between body composition measured by computed tomography (CT) and mortality in young women recently diagnosed with breast cancer, identifying the best correlated cutoff point. According to the results obtained in the first study (n = 34), early nutritional intervention was associated with low gastrointestinal chemotoxicity (nausea, vomiting and constipation, p < 0.001, p < 0.048 and p < 0.024, respectively). However, there were no statistically significant differences between the two groups (Control Group – CG and Intervention Group – IG) regarding the presence of long-term adverse events (radiotherapy toxicity - 88.2% vs 76.9%, weight loss - 21.1% vs 26.7% for IG and CG, respectively, p > 0.05 for both). The results of the second study (n = 192) showed that overall mortality occurred in 12% of women. Stages III–IV were the most frequent (69.5%). Women who died had a lower muscle area index (p < 0.05). A higher assessed muscle area (MC) was inversely associated with mortality. For each reduction of 1 cm2/m2 in the skeletal muscle index, the risk of mortality increased by 9%. Higher values of adiposity compartments were independently associated with higher mortality, despite a lower magnitude of risk. The findings of this thesis reinforce that early nutritional intervention may be associated with a lower frequency of early events, but not with long-term adverse events in women with breast cancer during treatment. In addition, they highlight the predictive significance of skeletal muscle area and adipose tissue in predicting survival among young women recently diagnosed with breast cancer.