Abstract P6-09-02: Knowledge of tumor/blood genomic testing (NGS) and ESR1 mutations in a survey of patients with ER+/HER2- metastatic breast cancer (mBC)

Abstract Introduction: In patients (pts) with ER+/HER2- mBC, acquired ESR1 mutations after endocrine therapy can lead to treatment resistance, metastasis, and poor prognosis. The objective of this survey was to understand the knowledge of NGS in pts with mBC. Methods: The 42-question, online EQUALS (ESR1 QUAlity of Life Survey) survey was sent to US subjects in June 2022 from 1) the Cure Media Group (n=6,625) by email, 2) private Facebook groups of pts with mBC and 3) members of a BC clinic. Eligible pts were those with ER+/HER2- mBC. At survey completion, respondents received a $10 gift card. Survey answers were summarized descriptively. Results: Of 236 pts who responded to the survey, 213 completed. Participants had a mean age of 57 y (range, 31–83 y), mean mBC diagnosis year of 2018 (range, 1995–2022), and were mostly white (91%), living in an urban/suburban setting (75%), with mean household income of ≥$75k (53%), and higher education degree (71%). First-line mBC treatments were aromatase inhibitor (AI) + CDK4/6 inhibitor (CDK4/6i; 44%), AI alone (18%), fulvestrant + CDK4/6i (16%), chemotherapy (12%), selective estrogen receptor modulator (SERM; 4%) or other/clinical trial (7%). Second-line therapies were none (31%), AI + CDK4/6i (28%), fulvestrant + CDK4/6i (18%), or AI alone (12%). Of the 54% (114/213) who received chemotherapy in the metastatic setting, 34% (39/114) had received ≥3 lines of chemotherapy. Pt’s oncologist gender (female 56%) and type (general [52%], breast cancer only [48%]) or setting (office [22%], community [35%], academic [43%]) of oncology practice were well balanced. Most pts’ oncologists (63%) had discussed tumor NGS by a blood test or tumor biopsy with them, but only 29% of them had explained liquid biopsy (assessment of circulating tumor DNA from a blood draw). Regardless, pts knew a lot/moderate amount about NGS (65%), less so of liquid biopsies (44%). NGS awareness by location was different with more suburban pts (73%) knowing a lot/moderate amount than urban (63%) or rural (59%) pts, and by income (>$50k [68%], $35k to <$50k [61%], <$35k [52%]), but not by age (< 50 y [71%]; 50-60 y [62%]; ≥60 y [69%]). When asked if they knew what an ESR1 mutation was, about a third each knew a fair amount, a little bit, or did not know much; only 24% of pts thought they had been tested for an ESR1 mutation. ESR1 awareness (Table) differed by location, with more urban pts (40%) knowing a lot/moderate amount about ESR1 mutations vs rural (30%) or suburban (26%) pts, by income (>$50k [32%], $35k to <$50k [28%], <$35k [14%]) and by oncologist setting (academic [39%] vs office [23%] or community [24%]), but not by age. Slightly more pts had an ESR1 test in urban (26%) vs rural (20%) settings, and with higher (29%) vs lower (10%) incomes, but similar by age. Overall, most pts believed that ESR1 testing results could affect their treatment options/decisions (92%), were comfortable asking about NGS (94%), and would prefer a blood test over a tumor biopsy for more targeted mBC treatments (88%). Conclusion: In this survey of ER+/HER2- pts living with mBC, most had some knowledge of NGS but knowledge of ESR1 mutations was lower. Discordance between physician discussion of NGS and liquid biopsies was observed. Awareness of NGS and ESR1 mutations analyzed by demographics data suggests socioeconomic disparities in pt education and knowledge. Further education on NGS and ESR1 mutations is needed as NGS testing is becoming an important aspect of mBC treatment. Table 1. Awareness of ESR1 mutations based on demographics *Never heard of it or heard of it but don’t know what it is. Citation Format: Jane Meisel, Sarah L. Sammons, Kelly Shanahan, Timothy Pluard, Monica Kozlowski, Dominic Carroll, Elizabeth Attias. Knowledge of tumor/blood genomic testing (NGS) and ESR1 mutations in a survey of patients with ER+/HER2- metastatic breast cancer (mBC) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-09-02.