Clinical implications of genomic-directed therapies by comprehensive genomic profiling in breast cancer patients at a large academic cancer center.

Abstract

e12037 Background: Increased use of comprehensive genomic profiling (CGP) has recently led to improved genomic characterization of tumors, increased access to individualized therapies and increased availability of clinical trials in breast cancer patients. The aim of this study was to evaluate the clinical impact of genomic profiling in breast cancer patients with the use of a CGP assay at a large cancer center. Methods: We retrospectively analyzed 101 consecutive breast cancer patients who received CGP at the John Theurer Cancer Center between 12/2011 and 08/2016. Genomic alterations (GAs) were identified using the FoundationOne assay (Foundation Medicine, Cambridge, MA). GAs, number of available genomic-directed therapies and number of available clinical trials were reviewed. The CGP interrogated up to 315 genes and introns of 28 genes. Results: Median age at diagnosis was 58 years (range: 35-83 years). With a median follow-up of 189 months (range 1-189), median survival was 163 months (range 142-184). A total of 560 GAs were found in our population, with a median of 5.0 GAs/sample (range 0-16), a median of 2.0 therapies/patient (range 0-11), and a median of 11.0 clinical trials/patient (range 0-36). The most frequent GAs found were TP53 (47.5%, n = 48), PIK3CA (34.7%, n = 35), MYC (22.8%, n = 23), CCND1 (19.8%, n = 20), FGF3 (16.8%, n = 17), FGF4 (15.8%, n = 16), and ZNF703 (14.9%, n = 15). A significant positive correlation was found between number of GAs and the number of available targeted therapies and clinical trials (r = 0.5 and r = 0.7, p = 0.00, respectively). Increasing age is a predictor of having a PIK3CA mutation (OR = 1.05; CI:1.01-1.09, p = 0.00) while decreasing age is a predictor of having a MYC mutation by logistic regression (OR = 0.95; CI:0.91-0.95, p = 0.03). Conclusions: The systematic use of CGP led to the identification of a high number of GAs, which correlated with a median of 2.0 individualized therapies and a median of 11.0 clinical trials available for breast cancer patients. The clinical impact of genomic-directed individualized therapies needs to be further investigated in prospective, randomized studies.