Abstract 1544: Association of tumor location with the breast and clinicopathological characteristics

Abstract

Abstract Introduction Tumor location within the breast varies, with the highest frequency in the upper outer quadrant (UOQ) and lowest in the lower inner quadrant (LIQ). What is not well understood is whether tumor location is prognostic. To determine whether tumor location is prognostic, associations between tumor site and clinicopathological characteristics were evaluated. Methods The Clinical Breast Care Project database was queried to identify all patients whose tumor site- UOQ, upper inner quadrant (UIQ), central, (LIQ), lower outer quadrant (LOQ) - was determined by a single, dedicated breast pathologist between 2001 and 2013. Patients with multicentric disease (n = 122) or tumors spanning multiple quadrants (n = 381) were excluded from further analysis. Clinicopathological characteristics evaluated included age at diagnosis, ethnicity, BMI, tumor stage, grade, and size, and hormone receptor, HER2 and lymph node status. Data was analyzed using chi-square and Mann-Whitney tests for univariate analysis with multivariate analysis performed using principal components analysis and multiple logistic regression. Significance was defined as P<0.05. Results Of the 980 patients with defined tumor location, 30 had bilateral disease. Tumor location in the UOQ (51.5%) was higher than in the UIQ (15.6%), LOQ (14.2%), central (10.6%) or LIQ (8.1%). Tumors in the central quadrant were significantly more likely to have higher tumor stage (P = 0.003) and size (P<0.001), positive lymph node status (P<0.001), and mortality rates (P = 0.011) compared to other quadrants. Analysis within each tumor size, however, found no difference in lymph node status by tumor location. After multivariate analysis, only tumor size and lymph node status remained significantly associated with mortality. Discussion Although tumors in the central region are associated with less favorable outcome, this association was driven by significantly larger tumor size, which has been associated with positive lymph node status. Tumors in the central region are known to be more difficult to detect mammographically and the majority of tumors in this region are palpable, thus, tumor location is not an independent prognostic factor, but rather less favorable prognosis, including larger tumor size, higher grade and more lymph node involvement in the central region can be attributed to delayed diagnosis. Citation Format: Seth Rummel, Nick Costantino, Matthew T. Hueman, Craig D. Shriver, Rachel E. Ellsworth. Association of tumor location with the breast and clinicopathological characteristics. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1544. doi:10.1158/1538-7445.AM2015-1544