Predictors of breast cancer development in a high-risk population

BACKGROUND: The purpose of this study was to investigate the strongest predictors of breast cancer in a high-risk population and to increase our understanding of the possible interactions between risk factors. METHODS: The Women At Risk High-Risk Registry provided the study population. The variables of interest included age at enrollment, presence of lobular carcinoma in situ (LCIS), atypical ductal hyperplasia (ADH), atypical lobular hyperplasia, family history of breast cancer, body mass index, and Gail scores (5-year high-risk > or =1.7%). Univariate and multivariate analyses were conducted with the Cox proportional hazards regression model and years of follow-up evaluation as the time scale. RESULTS: Out of 1553 high-risk women, 79 (5%) developed breast cancer during a median follow-up period of 5 years. Results from the multivariate Cox model demonstrated that FHBC (hazard ratio HR] = 1.76; 95% confidence interval CI], 1.05-2.97), ADH (HR = 1.90; 95% CI, 1.16-3.13), LCIS (HR = 1.71; 95% CI, .99-2.95), and a body mass index > or =30 (HR = 2.22; 95% CI, 1.14-4.35) were statistically significant predictors of breast cancer within this high-risk population. CONCLUSIONS: These results support current literature showing the synergistic increase in risk for patients with ADH, LCIS, and a positive family history of breast cancer. Obesity was also a strong predictor of breast cancer risk, which suggests that there may be a potentiating effect of obesity on other risk factors. Obesity may represent a modifiable risk factor, providing women with an opportunity to reduce their risk with lifestyle modification. Women with a strong family history of breast cancer or a diagnosis of ADH or LCIS may benefit most from risk-reduction strategies, chemoprevention, and surveillance.