Uptake of risk-reduction, surveillance, and therapeutic interventions among patients with breast cancer with pathogenic germline variants.

10579 Background: Management of breast cancer (BC) patients with pathogenic germline variants (PGVs) can include risk-reducing bilateral mastectomy (BLM), PARP inhibitors (PARPi), enhanced breast imaging (MRI/tomosynthesis), risk-reducing salpingo-oophorectomy (RRSO) and pancreatic cancer surveillance (endoscopic ultrasound, EUS/MR cholangiopancreatography, MRCP). We assessed intervention uptake in >1,400 PGV-positive BC patients. Methods: Germline genetic testing (GGT) data (Invitae Corp.) and insurance claims data (Komodo Healthcare Map) were assembled for female patients with BC or DCIS diagnosed 2015-23, GGT 1 year of claims post-GGT. Inclusion/exclusion criteria followed prior work (PMID 32027353). Genes analyzed were those conferring high (>50%; BRCA1, BRCA2, CDH1, PALB2, PTEN, STK11, TP53) or moderate (20-50%; ATM, BARD1, CHEK2, NF1, RAD51C, RAD51D) BC risk. Multivariable logistic regression models of intervention use included PGV risk, race/ethnicity, age, family cancer history, local metastasis, type of insurance, geographic region and time from diagnosis to GGT. Chi-square tests were used to compare intervention uptake rates by PGV risk (Table). Results: 1,432 patients had >1 PGV in a high- (51%) or moderate-risk (49%) gene: 68% White, 32% lymph node involvement, 69% BC family history, 28% Medicare/Medicaid, mean (SD) age at testing: 51 (12) and mean (SD) days from diagnosis to GGT: 40 (26). The intervention with the highest uptake was BLM (60% in all PGV carriers). BLM, RRSO, and PARPi were significantly more frequent in high- vs. moderate-risk PGV carriers. In the multivariable model, patients with BLM uptake were younger (odds ratio, OR 0.9, 95% confidence interval, CI 0.9-1), more often had family cancer history reported (OR 2, 95% CI 1-3) and had high-risk PGV (OR 5, 95% CI 3-7). Patients with RRSO uptake had higher odds of pancreatic (OR 2, 95% CI 1-2) or ovarian (OR 2, 95% CI 1-3) cancer family history and high-risk PGV (OR 6, 95% CI 4-8) and lower odds of Medicare (OR 0.4, 95% CI 0.2-0.8). Conclusions: Overall, the uptake of interventions was higher in patients with high- compared to moderate-risk PGV. More research, however, is needed on the shared decision-making process, as uptake of BLM was relatively high in those with moderate-risk PGV, and uptake of surveillance measures was relatively low.Table: see text