Abstract 873: Prevalence and correlates of HER2/neu overexpression among invasive breast cancer cases in two hospitals in Puerto Rico

Abstract

Abstract Introduction Breast cancer (BC) is the most common female malignancy in Puerto Rico. Cases with human epidermal growth factor receptor 2 (HER-2)/neu oncoprotein overamplification are consistently associated with poor prognosis, poor response to endocrine treatment, and an increased likelihood of recurrence. The objective is to evaluate the prevalence of HER2 /neu gene overexpression among a hospital-based female population of BC cases in Puerto Rico, and to determine its association with other clinical characteristics. Methods This cross-sectional study analyzed data from female patients with invasive BC diagnosed between 2000 and 2005, at the I. Gonzalez Martinez Hospital and the Auxilio Mutuo Hospital (n=1,082) in San Juan, Puerto Rico. Information on Her-2 status and other clinical characteristics was retrieved form the hospital's cancer registries and from medical record review. This study was approved by the Institutional Review Boards of the participating hospitals. Logistic regression models were used to evaluate the associations between relevant clinical characteristics and Her-2 status. Results: The prevalence of Her-2/neu overexpression in our study aas 20.9%, whereas 72.3% of the cases were ER positive and 59.3% were PR positive. In multivariate analysis, women with an age at diagnosis ≤ 50 years were 1.74 (95% CI=1.26-2.41) times more likely to be Her-2 positive as compared with those with an age at diagnosis ≥ 50 years. Regarding ER/PR status, women with ER+/PR- and those with ER+/PR+ were 1.97 (95% CI=1.30-2.98) and 2.15 (95% CI=1.49-3.10) times more likely to be Her-2 positive as compared to those with ER-/PR- status. Finally, women with invasive ductal histology were 1.79 (95% CI=1.08-2.95) more likely to be Her-2 positive as compared to those with invasive lobular histology. Women with tumor grade III/IV, tumor size ≥ 2 cm and lymph node metastasis were also more likely to be Her-2 positive (p<0.05). Conclusions: The prevalence of Her-2/neu overexpression in this population of Puerto Rican patients (20.9) and its association with earlier age at diagnosis, tumor size, lymph node metastasis and other clinical characteristics shows that BC patients with Her-2 positive tumors followed similar profiles as Her-2 positive BC patients in the US population. Results from this study will be useful for the development of future BC prevention and control strategies in Puerto Rico. Sponsors: This work was supported by an unrestricted grant from Glaxo SmithKline with additional support from the National Institutes of Health and National Center for Research Resources (NCRR) [grant number G12RR03051 and U54CA96297]. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 873.