Full-field digital mammography systems should be downclassified to Class II, supported by revised guidance as a special control, FDA's Radiological Devices Advisory Panel recommended May 23.

"The level of technology has been developed, tested and has shown clinical effectiveness" sufficient to justify downclassification, summarized voting panel member John Bourland, PhD, University of Washington, Seattle.

At the Gaithersburg, Md., meeting, the panel voted unanimously (7-0) to recommend reclassification.

Now regulated as Class III, full-field digital mammography (FFDM) systems approved to date have required submission of a full PMA. Class II status would allow clearance via the less burdensome 510(k) route, lowering barriers to entry for new systems.

"Our understanding of FFDM technology has improved to the point that we can develop appropriate special controls so that we can assure adequate safety and effectiveness through the 510(k) process," CDRH Office of Device Evaluation Radiological Branch Chief Robert Phillips said during a presentation to the panel.

Panel members based their recommendation on results of the 42,000-patient Digital Mammography Imaging Screening Trial (DMIST), by Etta Pisano, MD, University of North Carolina at Chapel Hill, et al. Results were published last September in the New England Journal of Medicine (¹ Also see "Digital Mammography More Accurate Than Film For Younger Women – NEJM" - Medtech Insight, 19 September, 2005., p. 11).

DMIST showed that FFDM is similar to film overall and more accurate than film for women younger than 50. Patients get 15% lower radiation dose with FFDM versus film, because digital imaging exposes only a portion of the breast.

Eliminating the need for the more extensive studies typically used to support full PMA submissions, downclassification would benefit patients as well as new entrants to the market, panel members suggested.

"I think the most compelling argument given to me is that by eliminating the need for subsequent PMA studies, we've eliminated the need for double exposure to patients undergoing those studies" for use in image comparisons, stated James Potchen, MD, Michigan State University, a temporary voting member.

FFDM systems approved via PMA, and now the market include GE Healthcare's Senographe 2000D , Fischer's SenoScan , Hologic's Selenia and Siemens' Mammomat Novation . GE was the only FFDM manufacturer to publicly support reclassification at the panel meeting.

"The four approved devices that have PMAs right now would become the predicate devices" for future 510(k)s, Phillips observed. FFDM technology developers also include Kodak, Fuji, Konica, Imaging Dynamics, Sectra and PlanMed.

The panel concluded that FDA guidance is adequate as the sole special control for FFDM Class II status. However, the advisory group proposed to include standardization for processing of soft copy images produced by FFDM systems.

"It is increasingly important as we go to soft copy that we develop some standards," Potchen said. "There is a wide variation in what we see" in soft copy FFDM images, and the guidance is an opportunity to regulate this, he explained. Many radiologists adhere to American College of Radiology standards for hard copy images, according to Potchen.

Guidance for 510(k) approval of these systems would be similar to current guidance on the PMA process, with a few differences in physical performance data and clinical data requirements, according to FDA.

A downclassification proposal and draft guidance will be available for public comment in the Federal Register, the agency said.

The panel's downclassification recommendation for FFDM has been more than a decade in the making.

The National Electrical Manufacturers Association (NEMA) argued in favor of 510(k) status during a 1995 panel meeting, but FDA felt at the time that safety issues necessitated PMA-type clinical data collection; since then, several 510(k) FFDM submissions have been denied by the agency (² Also see "FDA Panel To Consider If Digital Mammography Is Ready For 510(k)" - Medtech Insight, 17 April, 2006., p. 14).

- Adosh Unni

Digital Mammography 510(k) Status Recommended By FDA Panel

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