Impact of a structured exercise program on cardiac function in women receiving anthracycline-containing chemotherapy: a randomized controlled trial

Publications

Effects of physical exercise concomitant with chemotherapy on cardiac functionality of women with breast cancer

Publication . Antunes, Pedro Miguel da Silva; Esteves, Maria Dulce Leal; Ascensão, António Alexandre Moreira Ribeiro de; Sampaio, Francisco Pedro Morais Dias de Almeida

Anthracycline-containing chemotherapy is commonly used in the treatment of hematologic cancers and solid tumors, including breast cancer. Despite its wellrecognized clinical efficacy, the use of anthracyclines is limited by dose-dependent and cumulative cardiotoxic risk. Additionally, breast cancer treatment is often multimodal, which can further increase the cardiac damage. The cardiac toxicity poses significant challenges, influencing therapeutic decision-making and exacerbate patients’ morbidity and mortality. Longitudinal studies have shown that cardiovascular diseases are one of the leading causes of death among women with breast cancer. As a result, various international agencies, such as the American Society of Clinical Oncology and the European Society of Cardiology, emphasize the importance of implementing primary prevention interventions. Exercise training is an accessible and cost-effective intervention with well-documented benefits for overall health. Preclinical studies have shown promising results in mitigating the cardiotoxic impact of anthracyclines. However, whether this potential cardioprotective effect translates to humans is a question that remains to be clarified. The objectives of this thesis were to conduct a literature review on this topic (Study 1 and 2) and, as the core of this doctoral program, to design a single-center, randomized controlled trial with two arms (exercise group vs. usual care group) (Study 3). The main objective of this trial was to analyze the impact of a supervised exercise training program on established markers of cardiac toxicity (i.e., left ventricular ejection fraction, global longitudinal strain, and cardiac biomarkers) in women with breast cancer undergoing curative anthracycline-containing chemotherapy. Secondary objectives included analyzing the safety of exercise training and its effect on cardiorespiratory fitness, physical functionality, and health-related quality of life. The program consisted of three sessions per week of combined training (i.e., aerobic and resistance training) during each participant's chemotherapy length (approximately 5- months). Through the literature review, supported by a systematic review with metaanalysis of randomized controlled trials (Study 2), we found that evidence on the effect of physical exercise on established parameters of cardiac toxicity was limited, as only four eligible studies were identified. Most of these studies had significant limitations, including designs not specifically aimed at evaluating the efficacy of physical exercise on the parameters of interest, small sample sizes, short training programs, and brief followup periods. The results of the meta-analysis did not show a significant effect of exercise training compared to non-exercise. However, an exploratory analysis, which included studies with training programs consisting of at least 36 sessions (n=3), revealed a superior effect of exercise training on resting left ventricular ejection fraction. This suggests that the length of the exercise training programs might be associated with the effect of exercise training on cardiac function. The results of the randomized controlled trial demonstrated that exercise training did not significantly prevent the decline in established markers of cardiac toxicity compared to control (Study 4). However, it was found that exercising was safe—no serious adverse events were reported during the exercise training sessions—and it significantly prevented the decline in cardiorespiratory fitness, physical functionality, and health-related quality of life (Study 4 and 6). Additionally, we found that the response of cardiorespiratory fitness among participants randomized to the exercise group was heterogeneous, which justified the analysis of potential predictors through an exploratory study (Study 5). The results revealed that the parameters associated with the response in cardiorespiratory fitness to training were baseline body mass index and total aerobic training metabolic equivalent of task per hour (MET-hour). In summary, the results of this thesis suggest that adding exercise training to standard breast cancer care does not provide benefits on established markers of cardiac toxicity in women undergoing anthracycline-containing chemotherapy. However, the findings of experimental works indicate that implementing a supervised exercise training program during chemotherapy is safe and can be a viable and effective approach for improving cardiorespiratory fitness, preventing the decline in physical functionality and healthrelated quality of life in this challenging patient population. Additionally, our study suggests that the total energy expenditure of aerobic exercise (i.e., MET-hour) may be a predictor of cardiorespiratory response.

2025-06Doctoral thesis

Open access