Low body mass index is an independent predictive factor of local recurrence after conservative treatment for breast cancer

Background. Obesity or increased body mass index (BMI) has been shown to ha ve two important adverse effects related to breast cancer. First, several s tudies have identified an association between increased BMI and advanced st age breast cancer. Second, increased BMI has been shown to be associated wi th poorer prognosis. In a previous report, we had identified low BMI as a r isk factor for local reccurence at five years. The objectives of this study were to evaluate the relationship between BMI and local control and to con firm this prognostic factor in a larger population with an important follow -up. Materials and methods. Between 1976 and 1988, 605 women with invasive breas t carcinoma less than 4 cm in diameter underwent conservative surgery with axillary dissection and radiation therapy. The median follow-up time was 82 months. The risk of local recurrence and distant metastasis was evaluated by univariate retrospective analysis using Kaplan-Meier method for the main clinical and histologic factors. Those found to be significant were entere d in a Cox model for multivariate analysis. Results. Since the beginning of the study, 80 patients had developed local recurrence. The 5 years and 10 years local control rates were 91 % and 83 % , respectively. Four parameters were independent predictive factors of loca l recurrence: Age lower than 40 years (HR = 2.42 95 % CI = [1.35-4.34]), BM I: elevation of one unit reducing the local recurrence of 0.92 95 %CI = [0. 85-0.99], multifocality of the tumor on pathological examination (HR = 2.12 95 % CI = [1.16-3.88]) and positive axillary nodes HR = 0.54 95 % CI = [0. 31-0.95]. Size of the breast was not a predictive factor for local cancer r ecurrence. Low BMI did not increase risk of distant. Conclusion. Our study offers new data concerning the possibility that thinn ess may be related to local recurrence of breast cancer.