Systematic Review of Clinical Utility and Longer Term Follow up of Afirma GEC Testing

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 270-310-Thyroid Neoplasia (posters)
Clinical/Translational
Saturday, April 2, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SAT 284
Richard T Kloos*, John W Hanna, Jeff Haroldson and Neil Barth
Veracyte, Inc., South San Francisco, CA
Background

Medical policy coverage for novel diagnostics requires demonstration of clinical utility defined as the use of a diagnostic to change patient management and improve patient health outcome. We aimed to conduct a systematic review of published studies to measure if the Afirma GEC has reduced unnecessary surgeries among patients with indeterminate thyroid nodules.

Methods

A systematic literature review was conducted in PubMed through November 10, 2015 using the keyword search phrase - thyroid gene expression classifier. Studies were included that reported results for GEC benign and GEC suspicious patients. We abstracted the rates of GEC benign and GEC suspicious results, operative rates in each group, malignancies found at surgery, and median follow-up. Meta analyses were constructed of the impact of patient management using the GEC compared with historical control groups reported in these studies, and longer-term follow-up when reported.

Results

The keyword search yielded 55 results of which 40 citations were excluded for not reporting on patients managed with the GEC. Fifteen studies report on use of the GEC to manage patients in clinical practice. Twelve report rates of GEC benign and suspicious results, two report on only GEC benign and one reports on only GEC suspicious. In the twelve studies reporting on consecutive patients managed with GEC testing the number of patients tested ranged from 13 to 322. In total 1,345 patients in the twelve studies underwent GEC testing that yielded a diagnostic result. Among these patients 615 (46%) were GEC benign, of which 58 (9%) underwent surgery and 7 (1%) were malignant. The GEC was suspicious in 730 (54%) patients, of which 543 (74%) underwent surgery and 243 (33%) were malignant. Three studies compared management with the GEC to historical control groups from their institutions and reported that 869 of 1,569 (55%) patients with indeterminate nodules proceeded to thyroid surgery. In comparison, across twelve studies 601 of 1,345 (45%) patients managed with the GEC proceeded to surgery, an 18% lower overall surgical rate than the historical control groups (p<0.01). Follow-up of GEC benign nodules was reported in four studies of 158 patients with a median follow-up range of 7-13 months. With a multi-set median follow-up of 8 months, 135 (85%) GEC benign patients remained un-operated.

Conclusion

Clinical utility of the GEC to reduce unnecessary surgeries was established in twelve published studies. Only 1% of GEC benign nodules were reported as histologically malignant, suggesting a very low false negative rate of the assay in real-world practice. Overall we found an 18% reduction in surgical rates among patients managed with the GEC compared to historical control groups. Studies reporting longer-term follow-up suggest that 85% of GEC benign patients remain un-operated.

Disclosure: RTK: Employee, Veracyte, Inc., Employee, Veracyte, Inc.. JWH: Employee, Veracyte, Inc., Employee, Veracyte, Inc.. JH: Employee, Veracyte, Inc., Employee, Veracyte, Inc.. NB: Employee, Veracyte, Inc., Employee, Veracyte, Inc..

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting/pr-resources-for-endo

Sources of Research Support: Disclosure: Drs. Kloos, Haroldson, Barth and Mr. Hanna are employees and equity owners of Veracyte, Inc.