The effect of obesity on recurrence pattern in early breast cancer patients.

Purpose: Obesity is a well known risk factor for breast cancer recurrence and poor prognosis. We studied the effect of body mass index (BMI) on recurrence pattern in early breast cancer patients.

Methods: This retrospective cross-sectional study analyzed the data of 2731 early stage breast cancer patients. Patients who had metastatic disease at the time of diagnosis and with unknown BMI values were excluded from study (N=276). Patients were classified into three BMI categories: normal body weight, overweight, and obese. The recurrent/metastatic sites of patients were grouped in 8 categories: local, contralateral, lymph node, bone, lung, liver, brain and others. The association between first relapse site of early breast cancer patients and BMI categories were evaluated.

Results: The median patient age was 48 years (range 18-92). The median follow up time was 40 months (range 1-284). During follow-up, 469 (17.1%) patients developed recurrence and/or metastasis. Of 2455 total patients, 853 (34.6%) were classified as having normal weight, 898 (36.2%) were overweighted and 704 (29.2%) were obese. In the whole patient group no relation between metastatic sites and BMI groups was noticed. The first primary metastatic sites were also not associated with BMI groups in pre and postmenopausal subpopulations. In obese patients, disease free survival (DFS) was shorter compared to normal weighted patients, but the difference was not significant. There was no significant difference between site-specific DFS in relation to BMI categorization. Obese and overweighted patients had significantly shorter overall survival (OS) compared to the normal-weight group (p=0.003).

Conclusion: Although obesity had no effect on recurrence pattern of early breast cancer patients, obese early breast cancer patients had shorter OS compared to their normal-weight counterparts.