Resistance-type Exercise Training in Postmenopausal Women Survivors of Breast Cancer

Background: In postmenopausal women, an alteration in body composition occurs as a consequence of the secretion of low levels of serum estrogens by the ovaries. Observing an increase in abdominal and mammary fat mass and a decrease in skeletal muscle mass, which is also accompanied by loss of muscle strength and physical function, which leads early to a sarcopenia. On the other hand, the increase in estrogen production by adipose tissue has been associated with an increased risk of breast cancer during menopause because the mammary parenchyma is particularly sensitive to this type of estrogen. For this reason, Hormone Therapy (Aromatase Inhibitors and Tamoxifen) is prescribed in women with estrogen receptor-positive breast cancer. Antineoplastic treatments (Chemotherapy and Hormonal Therapy) have contributed to non-metastatic breast cancer currently presenting a high survival rate, not without adverse effects associated with the course of the disease, age and antineoplastic treatment, affecting various systems, but particularly skeletal muscle mass. Therefore, resistance exercise training has been proposed as an effective intervention strategy to increase muscle mass and strength in different populations. However, the level of muscle response to this type of training in postmenopausal women survivors of breast cancer with and without hormone treatment (Aromatase Inhibitors and Tamoxifen) is unknown.