The role of Ki-67 proliferation index vis-à-vis Oncotype DX.

Abstract

e11055 Background: Most newly diagnosed patients with invasive breast cancer have node negative disease. A key question in management of these patients is the risk/benefit ratio of adjuvant chemotherapy. Several microarray tests have been developed and are currently used to help identifying the patients who will benefit from adjuvant chemotherapy. Ki 67 proliferation index is less expensive and has been used as a prognostic and predictive factor in node positive breast cancer and neoadjuvant setting. Methods: Forty five cases of T1-2 N0 M0 (ER positive, HER2/neu negative) breast cancer were reviewed. Oncotype Dx results were available for all patients. Tumor specimens were stained for Ki 67. Results: The median of Ki 67 index was 17 (range 2-90). The median Oncotype recurrence score was 17 (range 7-60). There was a strong linear correlation between Ki67 index and Oncotype recurrence score (correlation coefficient= 0.74, P value= 0.000). This correlation was stronger in tumors with Ki 67 proliferation inde...