OBJECTIVE: Patients with breast cancer (BC) who are obese or overweight at the time of diagnosis have a low survival rate and a high death rate. We aimed to investigate if having a higher body mass index (BMI) at diagnosis raised the risk of local recurrence (LR) and distant metastasis.

PATIENTS AND METHODS: Patients were divided into three categories based on their BMI. The patient's BMI was determined by dividing his weight in kilograms by his height in square meters (kg/m²). The WHO defines normal weight as 18.5 ≤ BMI < 25 kg/m², overweight as 25 ≤ BMI < 30 kg/m², and obesity as BMI ≥ 30 kg/m².

RESULTS: The mean BMI was 30.27±6.06 kg/m². Out of 250 patients, 60 (24.0%), 73 (29.2%) and 117 (46.8%) patients had normal, overweight and obese BMI respectively. No significant difference between BMI and estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2) was found, but there was an association between tumor (T) stage and lymph vascular invasion (LVI) (p<0.05). Obese patients had poorer disease-free survival (DFS) and overall survival (OS) than normal and overweight categories (35.38 ±1.72 vs. 42.38 ± 2.79 and 37.82 ± 2.27 months) (39.65±1.65 vs.45.70 ± 2.53 and 44.31 ± 2.04 months) (p<0.001). LR occurs more prevalent in over-weight and obese patients than normal (p<0.03) but there is no significant difference for distant metastasis.

CONCLUSIONS: There is a strong negative association between increased BMI and BC prognosis and patient survival; controlling of this phenomenon may improve the response to treatment and survival, therefore health awareness programs should be implemented.