The health benefits of exercise against chemotherapy-induced skeletal muscle loss ; Os benefícios do exercício físico na atenuação da perda de massa muscular induzida pela quimioterapia

Paraneoplastic conditions such as cancer-associated cachexia and sarcopenia are often exacerbated by chemotherapy, which affects the patient’s quality of life as well as the response to therapy. In order to prevent or treat the muscle changes underlying these conditions, therapeutic approaches that include physical exercise programs have been suggested. In this thesis we describe the existing knowledge about the chemotherapy induced skeletal wasting, at function, mass and molecular levels, as well as the counteracting effects that exercise have on this condition, namely on increasing protein synthesis and decreasing muscle proteolysis. For that purpose, we performed two reviews: one focused on chemotherapy-induced molecular and functional changes in skeletal muscle and the other focused on the molecular and functional interplay between physical exercise and chemotherapy on skeletal muscle remodeling. Next, to bring more insights about the impact of chemotherapy and physical exercise on skeletal muscle of cancer patients, we explored the effect of a prehabilitation program in gastric cancer treated with FLOT, a recent neoadjuvant regiment. Our data suggests no changes promoted by chemotherapy nor prehabilitation (with WHO recommended physical activity (PA group) or structured exercise program (EXER group)) in anthropometric measures, but handgrip strength was reduced in men from EXER group after neoadjuvant chemotherapy. Albumin was significantly reduced only in the EXER group and HbA1c was increased in both EXER and PA group after neoadjuvant chemotherapy. No significant changes were detected on SkM regarding histological analysis (observational) nor in molecular players involved in SkM protein synthesis or proteolysis. Further pre-clinical and clinical studies with more defined criteria, molecular analysis of muscle samples as well as supervised exercise training to guarantee the fulfilment of protocol are needed to understand if exercise can be an effective strategy against muscle wasting induced by cancer and ...