32 Background: Oncotype DX breast cancer 21 gene assay recurrence score (RS) is used to predict disease recurrence and response to chemotherapy in order to offer patients the highest treatment benefit to risk ratio. There is a dearth of literature on the relationship of Oncotype RS and race in women with hormone receptor positive and node negative/positive disease. The purpose of this study was to investigate the relationship of race and clinical characteristics (including Oncotype RS) in an insured population of highly screened women with newly diagnosed breast cancer. Methods: The Breast Cancer Database of our institution was queried for patients who were newly diagnosed with breast cancer. We looked at demographics, risk factors, tumor characteristics, and Oncotype RS. Statistical analyses included Pearson’s Chi-Square and Fisher’s Exact Tests. Results: A total of 1,767 women were diagnosed with breast cancer from 1/2010 to 4/2014. The median age was 59 years. There was a total of 1327 (75%) Whites, 162 (9%) Blacks, 163 (9%) Asians, and 108 (6%) Hispanics. Majority of patients had a college-level education (83%), had annual/biannual screening mammography (78%), and clinical breast exams (89%). Majority of patients had invasive ductal carcinoma (61%), early stage (0, I, II) tumors (94%), ER+ (85%), PR+ (72%), Her2-negative (86%), and node-negative disease (80%). Compared to Whites, there was a significantly higher proportion of later stage disease among Blacks (p = 0.001) and Asians (p = 0.003), more triple negative breast cancers among Blacks (p < 0.0001) and higher Ki-67 scores among Blacks (p < 0.001) and Asians (p < 0.001). Oncotype RS was not significantly different among the race categories and a majority of patients had a low Oncotype RS (57%). These results did not change after stratifying for nodal status. Conclusions: In a population of women who had health insurance and were highly screened, we found clinical differences among races with respect to tumor histology. However, we did not find a statistically significant difference among race and Oncotype RS, even after stratifying for nodal status. Further studies are warranted to determine which tumor proliferation markers are contributing to ethnic differences in breast cancer mortality.
Relationship of Oncotype Dx score with tumor grade, size, nodal status, proliferative marker Ki67 and Nottingham Prognostic Index in early breast cancer tumors in Saudi Population
