THE INFLUENCE OF OBESITY ON THE DISEASE-FREE SURVIVAL IN PRIMARY BREAST-CANCER

Hyper-estrogenism is more common in obese than in non-obese women. Con sequently obesity has been shown to increase the risk of hormone depen dent tumors. Some investigators have claimed that obesity at the time of primary treatment may be an independent prognostic factor for breas t cancer, but this issue is still controversial. Therefore, we conduct ed a retrospective analysis to assess the influence of obesity at the time of primary treatment on disease-free survival (DFS). Obesity was defined as an excess of more than 25% of ideal weight according to Bro ca's index ([Height (cm) -100]) 10%). The Cox-model was used for multi variate analysis. Mean follow-up was 61 (range 6-126) months. 295 (62. 3%) patients were classified as of normal weight and 178 (37.6%) as ob ese. Mean excess of ideal weight was 8.9 kilograms (kg) in premenopaus al and 13.9 kg in postmenopausal patients (nonparametric t-test p<0.00 001). Patients with tumor size <20mm, 20-50mm and >50mm had a mean exc ess of the real weight of 10.6kg, 12.5kg and 16.1kg, respectively (non -parametric t-test p<0.0001). Percentual excess of real weight compare d to ideal weight was 22.4 [+/-21.2] kg in patients without recurrence and 21.5 [+/-21.9] in patients with recurrent disease (nonparametric t-test p=0.7256). Univariate analysis revealed no significant associat ion between obesity and the DFS. Multivariate analysis identified axil lary lymph node involvement as the only statistically significant prog nostic factor for disease-free survival (RR 1.55; 95%-confidence inter val 1.02-2.36; p:0.0368). Because of the high correlations of node-sta tus, tumor size and histological grading, the other factors failed to be prognostically relevant in this analysis. Obesity was not found to influence DFS of patients with primary breast cancer and is therefore unlikely to constitute an independent prognostic factor. It may, howev er, contribute to delayed diagnosis, since a significant proportion of obese patients were diagnosed with local advanced disease.