Effect of body mass index on metastatic pattern in early breast cancer patients.

e11553 Background: Obesity is well known risk factor for breast cancer recurrence and poor prognosis. However there is no data available about the effect of obesity on metastatic pattern in early breast cancer patients. Therefore, we aimed to asses the effect of obesity on metastatic pattern in early breast cancer patients. Methods: We retrospectively evaluated the data of 2973 early breast cancer patients who were admitted to Hacettepe University Cancer Institute between years 2002 and 2013. Patients who had BMI values at the time of diagnosis were included into the study. Patients were grouped according to body mass index (BMI) as follows; < 25 kg/m2 (Normal), > 25 – 29 kg/m2 (overweight), ≥ 30 kg/m2 (obese). Metastatic site of patients were grouped in 9 sites; local, contralateral, lymph node, bone, lung, liver, bone marrow, brain and others. For these sites we calculated the site specific disease free survival for each one. The effect of BMI groups on disease free survival (DFS) and overall survival (OS) for each metastatic site was assessed statistically. Results: The median age of patients was 48(min-max:18-92) years. Median BMI at the diagnosis of breast cancer was 27 kg/m2. Median follow up time was 40 months. During this time period 662 (22.3%) patients had recurrence and / or metastasis. Eleven percent of the patients died. DFS and OS were shorter in obese group (p=0.049 and p=0.003, respectively). Site specific DFS for local, contralateral, lymph node, lung, liver, bone marrow and brain sites were not statistically different between BMI groups. Only the bone metastatic site specific DFS was shorter in obese BMI group significantly. 3 –year DFS for bone metastasis were 92% (normal weight), 93% (overweight) and 88% (obese). Conclusions: Obese patients had shorter DFS and OS. Only thebone metastatic site specific DFS was significantly shorter in early breast cancer patients. In conclusion, obese patients may develop earlier bone metastasis compared to normal body weight patients.