Abstract

Obesity is an established risk factor for breast cancer, with particular significance in postmenopausal women. The pathophysiology involves estrogen production in adipose tissue after menopause, leptin-mediated tumor cell proliferation, chronic inflammation, and insulin resistance. Obesity can also develop post-diagnosis and during treatment, with younger premenopausal women more susceptible to weight gain. Weight gain was more common in women who had used certain chemotherapy regimens. While endocrine therapies such as tamoxifen or aromatase inhibitors do not significantly contribute to weight gain, they may elevate the risk of type 2 diabetes and cardiovascular disease. Obese breast cancer survivors demonstrate increased incidence of lymphoedema, cancer recurrence, and mortality compared to normal-weight counterparts. Multidisciplinary interventions incorporating dietary modification, physical activity, and psychosocial support have shown efficacy in weight reduction and quality of life improvement. Therefore, weight management strategies should be integrated early in breast cancer treatment protocols. Further research is needed to determine whether obesity interventions can mitigate breast cancer recurrence or mortality, assess long-term weight loss maintenance, and identify optimal body mass index targets to minimize complications. High-quality, longitudinal intervention studies are crucial to address these questions and enhance outcomes for breast cancer patients and survivors.