Measuring real-world concordance with evidence-based guidelines for genetic testing in patients with breast cancer: A retrospective quality review.

Abstract

e22542 Background: Genetic testing plays an important role in the detection and management of breast cancer. Patients with high-risk mutations may undergo more frequent screening and possible risk reduction with medical and surgical management. Genetic testing also guides treatment decisions, including the recent approval of adjuvant olaparib for patients with high-risk BRCA1/2-mutated early-stage breast cancer. The most recent NCCN guidelines expand the age recommendation for genetic testing for patients with a personal history of breast cancer from age ≤ 45 years to ≤ 50 years though in clinical practice, it is likely patients age 46-50 were undergoing genetic testing prior to this recommendation. The goal of this quality review was to assess real-world concordance with genetic testing as per NCCN guidelines and evaluate practice patterns of genetic testing in patients age 46-50 at two large academic centers with a diverse patient population. Methods: We conducted a retrospective quality review of patients age ≤ 50 years diagnosed with early-stage breast cancer at two academic centers from 2019 to 2021. Imaging, pathology, and genetic testing were abstracted from medical records. Baseline characteristics included age, gender, race, ethnicity, stage at diagnosis, receptor status, and genetic testing data. We used descriptive statistics to describe the population and genetic testing results. Results: There were a total of 376 patients with an average age of 44 years. Of these patients, 374 (99%) were female, 158 (42%) white, 76 (20%) African American, 60 (16%) Asian, and 77 (20%) identified as Hispanic. There were 255 patients (68%) diagnosed with stage I cancer, 82 (22%) with stage II, and 39 (10%) with stage III. There were 261 patients (69%) with hormone-receptor positive, HER2-negative cancer and 45 patients (12%) with triple-negative breast cancer (TNBC). Of the 230 patients age ≤ 45, 225 (98%) completed genetic testing. Of the patients who did not undergo genetic testing, 2 were offered and declined. Genetic mutations were found in 25 patients including 13 patients with BRCA1 and 4 patients with BRCA2. Of the 146 patients age 46-50, 134 (92%) completed genetic testing. Excluding patients with TNBC as genetic testing is recommended at any age for patients with TNBC, 115 patients (91%) underwent genetic testing. Mutations were identified in 8 patients including 3 patients with BRCA1 and 2 patients with BRCA2. Conclusions: Genetic testing is a key component of the pre-treatment diagnostic evaluation for patients with breast cancer given implications for management. Our study demonstrated nearly all patients age ≤ 45 with early-stage breast cancer underwent genetic testing, reflecting concordance with evidence-based guidelines. Furthermore, most patients age 46-50 at our institution had undergone genetic testing prior to the expanded NCCN guidelines.