Oncology Women with low muscle mass have worse prognosis in the treatment of breast cancer
Study conducted at USP in Ribeirão Preto evaluated data from 54 newly diagnosed patients with early stage disease
Oncology
Women with low muscle mass have worse prognosis in the treatment of breast cancer
Study conducted at USP in Ribeirão Preto evaluated data from 54 newly diagnosed patients with early stage disease
FERNANDA BASSETTE | Agency FAPESP – Maintenance of muscle mass has been shown to be a crucial factor for cancer treatment patients. Studies show that individuals with more muscle tend to respond better to therapies, such as chemical and radiotherapy, as well as less risk of complications and more effective recovery. This is because muscles play an essential role in metabolism, helping to regulate the inflammatory response and absorption of medicines. Oncological patients with low muscle mass, on the other hand, have a higher risk of toxicity during treatments, which can lead to worse prognosis and lower survival rate.
Study conducted at the Ribeirão Preto Medical School of the University of São Paulo ( FMRP-USP ) with support FAPESP evaluated data from recently diagnosed breast cancer women and confirmed that those with lower muscle mass at the beginning of follow-up presented a worse prognosis indicative compared to those of muscle mass considered normal. The results were published in the magazine Discover Oncology
The work is part of a secondary analysis of a larger study, which explored metabolic changes related to chemotherapy in women with breast cancer. The idea of the researchers was to evaluate the possible associations between muscle mass markers, evaluated by computed tomography and the phase angle result (a measure obtained in the analysis of bioimpedance).
In all, 54 patients were recruited at the Mastology Outpatient Clinic of the FMRP Hospital das Clínicas, a regional reference in Brazil. They had been diagnosed with early -stage breast cancer and were referred to chemotherapy. Before starting treatment, all underwent anthropometric evaluations, bioimpedance test, computed tomography (with third back vertebra clipping analysis), as well as physical function tests (manual grip force, marching speed test and fatigue assessment) and blood tests.
According to the nutritionist MIRELE SAVENAGO MIALICH GRECCO author of the article and researcher at the Department of Health Sciences of FMRP-USP, women with breast cancer are predisposed to mass loss, impairment of muscle quality and decreased force during treatment. And these changes can serve as predictors of adverse results, including mortality.
The choice of this audience for the study occurred because there are many overweight or obesity patients, which may end up masking the real situation of the patient's body composition. “Often overweight gives a false impression that everything is fine with this woman, as if she had a greater reserve of muscle mass. Treatment has a high toxicity and generates a very important inflammatory response, which favors the reduction of muscle mass along the journey,” he explains.
Grecco points out that the patient with breast cancer, most of the time, does not have the stereotype of an cancer patient with tumors in other regions, which tends to lose weight faster and more evidently – and this may disrupt the finding that there is loss of muscle mass. “If we do not evaluate this woman more deeply, mass decrease can go unnoticed,” he says.
Path to the results
Chest tomography is an exam that is part of the treatment routine of these patients. The researchers decided to cut the images (specifically in the lower back, vertebra L3) to analyze the amount and quality of muscle mass of women with cancer before they started chemotherapy or any other intervention for treatment.
As in clinical practice computed tomography are not always available or are impracticable to evaluate body composition, researchers have also analyzed the phase angle (PHA) as an alternative method. This is a measure associated with membrane integrity, obtained by bioimpedance analysis. It is a quick and noninvasive tool that can reflect body composition.
“It is a portable, low -cost and widely accessible method to evaluate individuals in clinical environments. But specific knowledge is required for the correct interpretation of results,” ponders Grecco.
Five years later, the researchers consulted the medical records of these patients to verify mortality in the period. The results showed that low muscle mass is significantly associated with reducing women's survival with non -metastatic breast cancer compared to those with normal muscle mass.
In addition, individuals with low muscle mass also had a lower phase angle and this was associated with a worse prognosis, which negatively affected patients' survival, regardless of cancer age and stage. According to Grecco, this means that phase angle measurement emerges as a promising marker of overall health and can be a valuable clinical tool in the prognosis assessment.
Real life impact
Breast tumor is one of the types of cancer that most kill women every year. In Brazil, the National Cancer Institute (INCA) estimates almost 74,000 new cases of the disease per year between 2023 and 2025 and 18,000 deaths. Only in 2023, according to the Ministry of Health, the public network recorded 60,866 cases of this cancer in women – 11% of them under 40 years of age.
According to the study, the prevalence of low muscle mass in cancer patients varies widely from 38% to 70%. For breast cancer specifically, studies report a prevalence close to 40%. In this population, reduced muscle mass has been associated with treatment failure, chemotherapy toxicity, decreased physical activity, tumor progression and less survival.
According to Grecco, muscle loss during cancer treatment is expected but is not desired. Therefore, precise assessment of body composition is essential to monitor metabolic changes related to the disease and guide directed nutritional measures, particularly in populations in which greater adiposity can mask the change. Thus, the objective of the study was to try to identify more practical and applicable measures in the clinical routine so that health professionals can do more interventions for these patients.
“Our idea with this work is to have a deeper look and propose an early intake earlier for this woman, as soon as breast cancer is diagnosed, indicating the amount of proteins required she would need to eat a day, for example,” says the nutritionist.
Another suggestion is that by accompanying the patient's muscle mass from the outset, the health professional forwards her to a physical exercise program within what her condition allows. “Especially for resistance and strength exercises, which will help preserve muscle mass a little more. The idea is not to promote muscle gain, but to minimize losses and give a better condition for this woman to hold on all cancer treatment,” says the researcher.
The article Association of skeletal muscle quantity and quality with mortality in women with nonmetastatic breast cancer can be read in: https://link.springer.com/article/10.1007/s12672-025-01999-1