Genetic testing into survivorship after diagnosis of breast cancer.

Abstract

10583 Background: Support for universal genetic testing after diagnosis of breast cancer is growing because of concerns that targeted guidelines fail to identify all patients who could benefit from genetic risk evaluation (GRE). Little is known about use of genetic testing in survivors of breast cancer over time. Methods: Women who were diagnosed with breast cancer in 2014-15 and reported to the SEER registries of Georgia and Los Angeles County completed a baseline survey about 9 months after diagnosis (N=2502). We performed a follow-up survey (FUPs) about 6 years after diagnosis among survivors (N=2347), of whom 1423 responded (60% response rate). We asked women about their receipt of clinical germline genetic testing and results, communication with relatives about cancer genetic testing, and use of direct-to-consumer testing (DTCt) after diagnosis. We categorized women into indications (yes/no) for GRE based on National Comprehensive Cancer Network guidelines at time of diagnosis (GRE indication baseline) and at the time of the follow-up survey (GRE indication FUPs only). Results: We present results for a preliminary sample (N=1272). About half of the respondents (44.6%) had indications for GRE over the study period; 28.0% at baseline; and an additional 16.6% at time of the follow-up survey (FUPs only). The Table below shows patient-reported testing at FUPs by GRE indication category (baseline, FUPs only, no indication). About two thirds of those with a baseline indication for GRE received genetic testing over the observation period: 66.5% vs 43.9% with indication at FUPs only vs 35.0% of those with no indication (p<.001). A substantial proportion of those who reported testing received the test during the survivorship period (1 to 6 years post-diagnosis): approximately one-third of those with baseline indications vs over half of those with GRE indication at FUPs only. Testers with a pathogenic variant result (n=59) were much more likely to have talked to most or all of their first-degree adult relatives about genetic testing than those with a variant of unknown significance (n=40) or a negative finding (n=382): 64.3% vs 35.0% and 37.1%, respectively (p<.001). Overall, there was very little interest in DTCt for cancer risk: 5.0% researched DTCt online somewhat to a lot; and only 3.5% had DTCt. Conclusions: The proportion of patients with indications for GRE after diagnosis of breast cancer markedly increases into survivorship but many patients do not receive genetic testing. Lack of survivor interest in DTCt for cancer risk is reassuring that patients are not substituting DTCt for clinical testing. [Table: see text]