Obesity in Terms of BMI and BSA in Egyptian Breast Cancer Patients: Can Tumor Behavior Be Predicted?

Abstract

Background: Obesity is a major health problem worldwide and is involved in etiology of breast cancer. Egypt is ranked among the highest globally in obesity problem. Body mass index (BMI) is the most widely used tool to define obesity. Body surface area (BSA) is another measure used widely in clinical practice, particularly in calculating doses of chemotherapeutic agents. Both Body Surface Area (BSA) and Body Mass Index (BMI) rely on weight and height and can be used as indicators of obesity. Patients and Methods: This is a cross-sectional observational study that was carried out in the department of clinical oncology, Faculty of medicine, Ain Shams University Hospitals. Medical records of patients scheduled for adjuvant chemotherapy were revised regarding age, comorbidity, side of the tumor, stage, and type of the surgery performed. Immunohistochemistry (IHC) to detect ER, PR, and Her2 and molecular subtypes of the tumors was recorded. BMI and BSA were calculated for all patients. Inclusion Criteria: Female patients with newly diagnosed breast cancer, cases that didn’t start the adjuvant treatment, data for IHC available, weight, and height of the patients recorded in the files. Exclusion Criteria: Male breast cancer cases, bilateral cases, metastatic cases, age above 80 years, cases with multiple primaries. Results: The mean age of patients was 48 ± 11 years and 60% of them were premenopausal. The mean weight in Kgs was 81 ± 13 and the mean height in cm was 156 cm ± 5. Mean BMI was 33.8 ± 6.0 and mean BSA was 1.84 ± 0.15. Comorbidities were present in 10.6% of patients. In the studied group of patients, tumors were more common of right side (55.7%), T2 tumor (40%), N1 (40.9%), and stage III in 57.4%. Regarding the hormonal receptor status, most of the patients were ER+ (76.5%), PR+ (66.1%) and Her2 ? (73.9%). The molecular subtypes were also estimated with HR+ subtype most common in (60%) and Her2+ subtype least common in (10.4%). Neither BMI nor BSA was different based on menopausal status. Tumor characteristics were compared in relation to BMI and BSA, and none of the studied parameters regarding menopausal status, T staging, N staging, TNM staging, ER, PR, Her2 and molecular subtype were significantly associated with BMI or BSA. Receiver operating characteristic (ROC) curve was done for the poor prognostic variables. It was found that both BMI and BSA were poorly predictive for the prognostic tumor characteristics regarding T stage, N stage, Her2 overexpression and TN disease. Conclusion: Obesity is a major health problem among breast cancer patients in Egypt. Both BSA and BMI (as indicators of obesity) in Egyptian breast cancer patients are higher compared to other parts of the world. Both BMI and BSA were poorly predictive of prognostic parameters in breast cancer patients.