(ChemotherapyAdvisor) – Physicians who received results of a gene-expression-based tissue-of-origin test for patients with difficult-to-diagnose primary cancers changed the primary site diagnosis for 50% of patients and treatment management for 65%, results of a study presented at the ASCO 2012 Gastrointestinal Cancers Symposium has found.
John C. Hornberger, MD, of Cedar Associates LLC and Stanford School of Medicine, Menlo Park, CA, and colleagues collected data from 65 physicians who had ordered the tissue-of-origin test. Detailed web-based and telephone interviews were conducted and a chart survey included patient demographics, imaging and immunohistochemistry (IHC), and therapy. “The physicians were queried regarding their working diagnoses and treatment recommendations prior to and after tissue of origin test result availability,” the investigators noted. “Date of death was also obtained with a minimum of one-year follow-up from date of biopsy.”
The registry included 107 patients, most of whom had undergone extensive evaluation (≥10 IHC) prior to gene expression analysis. The test results led physicians to change the primary site diagnosis for 53 patients (50%; P<.001) and treatment management for 72 patients (65%; P<.0001). At last follow-up, 69 patients had died; median survival was 426 days. At 1,000 days, >30% of patients were alive. “Survival outcomes compare favorably to historical controls in treatment trials where median survival is generally less than one year,” they concluded.