Abstract P2-02-06: Genetic counseling, germline genetic testing, and impact of results in patients with newly diagnosed breast cancer

Abstract

Abstract The surge in BRCA1/2 and multiple-gene panel testing after a diagnosis of breast cancer has fueled concerns about how genetic testing results will be integrated into patient management. However, there is virtually no research about the timing or extent of genetic counseling before or after testing or the impact of genetic results on bilateral mastectomy (BLM) use since the advent of more widespread testing. Methods: A population-based sample of 3600 patients newly diagnosed with breast cancer identified by two SEER registries (Georgia and Los Angeles County) were sent surveys two months after surgery (Dx dates 2014-15) about their genetic testing and treatment experiences. Survey information was merged with SEER data. We examined patterns and correlates of counseling and genetic testing and the impact of results on patient preferences for BLM and receipt of BLM. Results: Among 2388 patients with unilateral breast cancer (response 70%), 697 (29.2%) had elevated pre-test risk of a germline mutation (based on age, family cancer history, ancestry, and tumor subtype). One-quarter of these higher risk patients (25.6%) did not discuss whether to have testing with any provider, 26.1% discussed it with clinicians only, and 48.3% had a visit with a genetic counselor. Half of patients with elevated pre-test risk (51.2%) were tested: 6.6% before diagnosis, 65.4% after diagnosis but before surgery and 28.0% after surgery. Higher risk patients who underwent testing were younger (p<.001) and had higher income (p=.029) but rates did not differ significantly by race, education, insurance, marital status, cancer stage, comorbidities, or geographic site after controlling for all covariates. There was wide variation in the type of professional who discussed test results with patients: discussed with surgeon only (17.8%), medical oncologist only (19.7%), both physicians but no counselor (4.8%), or genetic counselors (56.8%). Among all testers in the total sample (n=667), 54 (9.4%) reported a pathogenic mutation (12.1% of higher risk patients vs 5.7% of low risk patients) and 59 (10.0%) reported a variant of unknown significance (VUS) (10.2% of higher risk patients vs 9.9% of lower risk patients), p=.027 for differences between groups. Two-thirds (60.4%) of patients with pathogenic mutations reported that the test made them more interested in BLM vs 8.8% of those with a VUS, and 11.4% of those with negative tests, p<.001. Two-thirds (69.2%) of those with pathogenic mutations received BLM vs 21.9% of those with VUS and 27.9% of those with negative tests, p<.001. Conclusions: Many patients newly diagnosed with breast cancer at higher risk of carrying a pathogenic mutation do not receive pre-test counseling or genetic testing and disparities are observed. There is wide variability in the timing of genetic testing after diagnosis and with which clinician the findings are discussed. Taken together, these results suggest that germline genetic testing after a diagnosis of breast cancer is poorly integrated into practice. However, the impact of genetic test results on patient attitudes and receipt of bilateral mastectomy suggests that genetic testing does help target prevention to a patient's future risk for a new primary breast cancer. Citation Format: Katz SJ, Morrow M, Jagsi R, Kurian A. Genetic counseling, germline genetic testing, and impact of results in patients with newly diagnosed breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-02-06.