Abstract P1-07-21: Relationship between hereditary cancer syndromes and oncotype DX recurrence score

Abstract

Abstract Background Oncotype DX Recurrence Score (RS) is used to stratify breast tumors into those likely to respond to cytotoxic chemotherapy. Women and men with hereditary cancers tend to have tumors that are chemosensitive. We hypothesize that a high RS may harbor a signal of potential hereditary risk. This analysis aims to identify whether breast cancer patients with hereditary cancer syndromes have a disproportionate amount of high RS compared to sporadic cases. Methods Individuals with a personal history of breast cancer who received treatment at participating research facilities and had hormone receptor positive breast cancer, Oncotype DX testing and hereditary cancer mutation testing were included. Oncotype DX RS was recorded along with the type of genetic testing and the genetic testing results. RS was categorized as low (0-17), intermediate (18-30), and high (31+). Those with deleterious mutations in any known hereditary cancer gene were considered positive. Individuals with a variant of uncertain significance (VUS) or negative genetic testing result were considered negative. Difference in distribution of tumors with low, intermediate, and high Oncotype DX results in those with hereditary breast cancers compared to those with sporadic breast cancers was determined with Chi-square. Results 419 patients with Oncotype DX testing from two clinical sites were collected from 2013. Of those, 123 underwent genetic risk assessment. Mutations identified included the following genes: BRCA1 (1), BRCA2 (5); CHEK2 (3); BRIP1 (3); NBN (2); MSH6 (1). Of those testing positive for a deleterious mutation, the number of patients with RS results in each category were 5, 4 and 6 for low, intermediate and high, respectively. For those considered negative on hereditary cancer panel testing, the RS results were 76, 52 and 8, respectively. Of those with high RS, 43% had deleterious mutations. Chi square test was statistically significant for a difference between the RS of those with deleterious hereditary mutations versus those with sporadic cancers (p = 0.000086). Conclusions High RS may indicate a higher likelihood of harboring a hereditary cancer syndrome. Further investigation with larger numbers and multivariate analysis is needed to validate if a high RS serves as an independent predictor of benefit from genetic counseling and testing. Citation Format: Toltzis S, Casasanta N, Lipinski S, Marino A, McHenry A, Denduluri N, Rodriguez P, Kaltman R. Relationship between hereditary cancer syndromes and oncotype DX recurrence score [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-21.