Abstract S2-2: Multivariate Analysis of Obesity and Disease Free Survival in Patients with Nodal Positive Primary Breast Cancer — The ADEBAR Trial

Abstract

Abstract Background: The prevalence of obesity increases throughout all evolved civilizations. On the other hand several epidemiological studies have shown not only an increase in breast cancer among obese women but also an adverse impact of obesity on survival of breast cancer patients. This analysis focuses on the impact of obesity on patients (pts) treated within the ADEBAR study protocol. Methods: The ADEBAR Trial compared 4 cycles of EC followed by 4 cycles of Doc vs. 8 cycles of FEC (120) in pts with primary breast cancer (>=4LN). 1500 pts have been accrued from sep/01 through may/05. For this analysis data of 1361 pts has been analyzed about the impact of obesity on disease free survival. Therefore pts have been grouped to either “underweight” (BMI<18.5kg/m2), “normal weight” (BMI18.5-25kg/m2), “overweight” (25kg/m2<BMI>30kg/m2) or “obese” (BMI>30). Results: 13 pts (1.0%) were “underweight”, 557 pts (40.9%) were normal weight, 491 pts (36.1%) were overweight, 300 pts (22.0%) were obese at the time of study enrollment. After a follow up period of 60 months 87.5% of the underweight group, 70.4% of the normal weight group, 70.7% of the overweight group and 58.6% of the obese group were alive with no signs of recurrent disease. This difference was significant (Chi-square=9.355; p< 0.0249). The tumor size at clinical diagnosis was strongly associated to the patient's weight (< 0.0001). There was no significant difference in the number of positive lymph nodes (p = 0.2890), tumor histology (p = 0.9750), grading (p = 0.9520), ER and PR hormone receptors (ER p = 0.9708, PR p = 0.7785) and the expression of HER2 (p = 0.1710) regarding underweight, normal, overweight and obese patients. In a multivariate analysis obesity was an independent prognostic factor with a hazard ratio of 1,007 per 1kg/m2 increase (P<0,0167). Conclusion: This analysis strongly implicates an impact of obesity on disease free survival in patients with early stage node positive breast cancer in the prospectively randomized ADEBAR multicenter trial. It is therefore in line with earlier findings in epidemiological research and raises the question whether a weight reduction might be an additional approach on breast cancer therapy. Figures available in online version. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S2-2.