t NEJM.org. From the School of Medicine, the Fuqua School of Business, and the Sanford School of Public Policy, Duke University, Dur- ham, NC. 1. National Comprehensive Cancer Network. NCCN clinical practice guidelines in oncology: breast cancer. 2015 (http://www.nccn.org/ profess iona Is/physician_gls/f_ guidelines .aspitsite)

where previous extensive molecular testing on tumors was negative. Approximately one third of patients were matched to therapies in accordance with National Comprehensive Cancer Network (NCCN) treatment guidelines, and approximately one third were matched to clinical trials enrolling at MSKCC at the time of testing. • In May, addi