How accurately can clinicians predict the Oncotype DX DCIS score?

Abstract

90 Background: The Oncoype DX DCIS Score was developed to assess the risk of recurrence for ductal carcinoma in situ, as well as an invasive breast cancer. It is a 12 gene assay performed on an individual patient’s tumor and is used to predict the ten year local recurrence risk of an ipsilateral breast event, which can be either an invasive breast cancer or ductal carcinoma in situ. It is also used to predict the 10 year risk of an invasive cancer. The DCIS Score was clinically validated using patients from ECOG 5194. The purpose of this study was to investigate how often clinicians, (medical oncologists, breast surgical oncologists, and radiation oncologists) can predict the DCIS Score. Methods: In this IRB approved study, we retrospectively reviewed the charts of 27 patients at our institution who underwent unilateral or bilateral partial mastectomy for DCIS from April 2012 to February 2013 and who had their pathology specimens submitted for DCIS Scores. Patient age range was 40-79 years old, with a mean of 56.8. All patients underwent consultation with radiation oncology. A chart was compiled to include the patient’s age and tumor histology. This included grade of DCIS, extent of DCIS, presence of necrosis, margin width, and hormone receptors. We then removed all identifying factors from the patients’ data, and surveyed our radiation oncologists, medical oncologists, and breast surgical oncologists on whether patients had a low, intermediate, or high DCIS Score. Results: Breast surgical oncologists accurately predicted the DCIS score 49% of the time. Medical oncologists predicted the DCIS score 35% of the time, while radiation oncologists were accurate 51% of the time. Conclusions: This study demonstrates the difficulty in predicting the DCIS Score. The information obtained from the DCIS Score is specific to the genetic behavior of each individual tumor, whereas traditional methods of predicting risk of recurrence and benefit of radiation are based on standard pathologic and clinical criteria. Further studies on larger patient populations need to be performed prior to wide scale acceptance of this genomic test. [Table: see text]