Integration of Universal Germline Genetic Testing for All New Breast Cancer Patients.

BACKGROUND: The American Society of Breast Surgeons recommends genetic testing (GT) for all women with breast cancer (BC), but implementation and uptake of GT has not been well-described. METHODS: A retrospective chart review was performed for newly diagnosed BC patients or patients with a newly identified recurrence of BC seen in a multidisciplinary clinic (MDBC) who were offered genetic counseling (GC) and GT. RESULTS: The 138 women attending the MDBC had a median age of 54 years and comprised non-Hispanic whites (46%), Asians (28%), Hispanics (17%), blacks (4%), and other (5%). Of the 105 (76%) patients without prior GT, 100 (95%) accepted GC, with 93 (93%) of these 100 patients undergoing GT. The patients meeting the National Comprehensive Cancer Network (NCCN) guidelines for GT were more likely to undergo GT. Testing was performed with a 67- to 84-gene panel, together with an 8- to 9-gene STAT panel if needed. Among 120 patients with reports available, including 33 patients previously tested, 15 (12%) were positive (1 BLM, 1 BRCA1, 3 BRCA2, 1 BRIP1, 1 CFTR, 1 CHEK2, 1 MUTYH, 1 PALB2, 1 PRSS1, 1 RAD50, 1 RET, and 2 TP53), 44 (37%) were negative, and 61 (51%) had an uncertain variant. The median time to STAT results (n = 50) was 8 days. The STAT results were available before surgery for 47 (98%) of the 48 STAT patients undergoing surgery. CONCLUSIONS: New BC patients attending the MDBC demonstrated high rates of acceptance of GC and GT. The combination of GC and GT can offer timely information critical to patient risk assessment and treatment planning.

Multicenter Prospective Cohort Study of the Diagnostic Yield and Patient Experience of Multiplex Gene Panel Testing For Hereditary Cancer Risk.

PURPOSE: Multiplex gene panel testing (MGPT) allows for the simultaneous analysis of germline cancer susceptibility genes. This study describes the diagnostic yield and patient experiences of MGPT in diverse populations. PATIENTS AND METHODS: This multicenter, prospective cohort study enrolled participants from three cancer genetics clinics-University of Southern California Norris Comprehensive Cancer Center, Los Angeles County and University of Southern California Medical Center, and Stanford Cancer Institute-who met testing guidelines or had a 2.5% or greater probability of a pathogenic variant (N = 2,000). All patients underwent 25- or 28-gene MGPT and results were compared with differential genetic diagnoses generated by pretest expert clinical assessment. Post-test surveys on distress, uncertainty, and positive experiences were administered at 3 months (69% response rate) and 1 year (57% response rate). RESULTS: Of 2,000 participants, 81% were female, 41% were Hispanic, 26% were Spanish speaking only, and 30% completed high school or less education. A total of 242 participants (12%) carried one or more pathogenic variant (positive), 689 (34%) carried one or more variant of uncertain significance (VUS), and 1,069 (53%) carried no pathogenic variants or VUS (negative). More than one third of pathogenic variants (34%) were not included in the differential diagnosis. After testing, few patients (4%) had prophylactic surgery, most (92%) never regretted testing, and most (80%) wanted to know all results, even those of uncertain significance. Positive patients were twice as likely as negative/VUS patients (83% v 41%; P < .001) to encourage their relatives to be tested. CONCLUSION: In a racially/ethnically and socioeconomically diverse cohort, MGPT increased diagnostic yield. More than one third of identified pathogenic variants were not clinically anticipated. Patient regret and prophylactic surgery use were low, and patients appropriately encouraged relatives to be tested for clinically relevant results.