RÉSUMÉ
Objective:To analyze the body composition of breast cancer patients and the changes with age; to compare the incidence of obesity in breast cancer patients with different diagnostic criteria; To understand the relationship between body mass index (BMI) and body composition; to investigate the incidence of sarcopenia and its relationship with obesity in breast cancer patients.Methods:The bioelectrical impedance technique was used to analyze the body composition of 1 187 female breast cancer patients before surgery.Results:There was a statistically significant difference between different age groups of breast cancer patients with various body composition indicators ( F values were 3.767-32.627, P < 0.01), and the incidence of obesity and sarcopenia was different in different age groups ( χ2 value was 20.819, P < 0.01). The obesity detection rate of different diagnostic methods was different. The obesity rate diagnosed by body fat percentage (PBF) was the highest. 28.14% (334/1 187) of breast cancer patients were diagnosed as "invisible obesity", which refers to normal or low BMI but excessive PBF. BMI was positively correlated with all body composition indicators ( r values were 0.137-0.954, P < 0.01), and moderately correlated with PBF and skeletal muscle mass ( r values were 0.761, 0.534, P < 0.01). The incidence of sarcopenia in breast cancer patients was 8.26% (98/1 187). 8.78% (64/1 187) of the patients with normal BMI were diagnosed as Sarcopenia. Among patients with excess PBF and excess visceral fat area, 6.70% (47/1 187) and 5.98% (15/1 187) were diagnosed with sarcopenia, respectively. Conclusion:The incidence of PBF obesity in breast cancer patients is high, and some patients have sarcopenia, which is not good for prognosis. Bioelectrical impedance technology can accurately assess the body composition of patients, and can find "invisible obesity" and sarcopenia that cannot be diagnosed by BMI, which is worthy of further promotion and application in clinical practice.