A comparative analysis of body mass index with estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 status in pre- and postmenopausal breast cancer patients

Background: Breast cancer is now the most common cancer among Indian women. Recent studies have suggested a possible link between risk factors like high BMI and molecular subtypes of breast cancer. Studies from Western and Asian population have shown varying relationship between post- menopausal obesity and expression of ER, PR, Her2-neu receptors in breast cancer patients. Aim: This study was done with an aim to explore if overweight or obesity as defined by BMI and status of ER, PR and Her2-neu receptors differ in Indian pre-menopausal and post-menopausal breast cancer patients. Methods and Material: This is a retrospective analysis of 446 breast cancer patients treated at Mahavir Cancer Sansthan, Patna from July to December 2019. Their case records were evaluated and data regarding age, menopausal status, height, weight and ER, PR & HER2-neu receptor status were extracted for analyses. Statistical Analysis: Chi-square test was used to compare categorical variables between the pre-menopausal and post-menopausal group. Results: The prevalence of obesity in the post-menopausal group was 2.3% more than the pre-menopausal group (P-value = 0.24). As compared to the pre-menopausal group, there was an increase in the ER/PR positivity in the post-menopausal group by 3.41% (P-value = 0.47) and in the Her2-neu positivity by 6.38% (P-value = 0.15). As compared to the pre-menopausal group, there was further increase in the ER/PR positivity in the post-menopausal group by 6.85% (P-value = 0.40) in sub-group of patients with BMI >= 25kg/m2. Conclusions: Our study showed slightly increased incidence of obesity in post-menopausal breast cancer patients. Overweight post-menopausal patients also had a higher percentage of ER/PR receptor positivity and lower percentage of Triple negative breast cancer. The percentage of Her2-neu receptor positivity was more in post-menopausal patients. A high BMI was found to be associated with a lower Her2neu positivity.