Breast Cancer Radiation Device Prompts Concerns Over FDA Quick-Review Process

Main Category: Breast Cancer
Also Included In: Medical Devices / Diagnostics;  Radiology / Nuclear Medicine;  Regulatory Affairs / Drug Approvals
Article Date: 29 Oct 2008 - 7:00 PST

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A device to treat breast cancer that was cleared for use in the U.S. under FDA's quick-review process raises concerns from critics that the agency is not thoroughly vetting some experimental medical devices before approval, the New York Times reports as part of a series of articles on medical treatments approved without strong evidence of efficacy. The device, MammoSite, has been used on about 45,000 breast cancer patients in the U.S. since FDA cleared it for use in 2002, even though it is still "highly experimental," according to the Times. MammoSite involves inserting radioactive "seeds" into the tumor site through a single balloon catheter, rather than using external beams to irradiate the entire breast. The treatment takes five days, compared with six weeks for conventional radiation treatment. Proponents of MammoSite say it offers the advantages of a shorter course of treatment and lower exposure to radiation, which some doctors feel can help convince women to consider radiation before undergoing a mastectomy.

MammoSite is one of thousands of medical devices FDA approves through the quick-review process each year "after only cursory review and with no clear evidence that they help patients," the Times reports. Congress created the quick-review process -- also known as a 510(k) review, after the section of law that enacted it -- when FDA began regulating medical devices in 1976. Because FDA's new regulation of medical devices would not apply to devices on the market before 1976, lawmakers were concerned that newer products would be at a competitive disadvantage. The 510(k) review addressed those concerns by allowing an expedited FDA review for new products deemed "substantially equivalent" to a product already on the market. In 2007, FDA cleared 2,640 of the 3,052 devices submitted under the 510(k) process, compared with the 27 out of 41 products approved through the full review process. The nonpartisan Government Accountability Office is expected to release a report next month in response to a Congressional request to study the effectiveness of the quick-review process.

According to the Times, under the quick-review process, "a product's effectiveness is never directly established" and "[r]egulators simply determine if the device does what its maker says it does -- in MammoSite's case, that it delivers radiation -- and whether it poses any undue safety risks." Once a device is approved by FDA, doctors are free to use the product without telling patients that the device is unproven, the Times reports. FDA officials say the quick-review process is necessary to promote innovation, and they argue that MammoSite's warning label provides sufficient evidence for doctors that the treatment has not been shown to be a substitute for conventional radiation therapy. Daniel Schultz, director of FDA's Center for Devices and Radiological Health, said extensive studies of new devices would be "very, very inappropriate and a waste of resources," as the majority of the products are simply an upgrade on an existing device.

The maker of MammoSite cited GliaSite -- a device that uses a balloon catheter to deliver radiation to treat advanced brain cancer -- as the "substantially equivalent" product in its FDA application. GliaSite also reached the market due to a 510(k) review in 2001. However, critics maintain that MammoSite is significantly different from any other product on the market, including GliaSite, because of the disease it treats and because GliaSite is typically used for patients who do not have the option of choosing another treatment, the Times reports. In addition, MammoSite was allowed onto the market based on a study involving 25 women that did not explicitly evaluate how effective the treatment is against breast cancer. Many cancer specialists argue there is still no conclusive evidence that it is as effective as conventional radiation, and the issue has created a debate among doctors over "whether there is enough evidence to feel comfortable recommending the treatment to women who are not part of a clinical study," according to the Times.

Critics also argue that relatively high reimbursements from insurers create a financial incentive for doctors to choose MammoSite over conventional radiation therapy. Medicare initially set the total payments for MammoSite treatment around $20,000 -- twice the amount for conventional radiation -- which is in keeping with Medicare's standard practice of offering larger payments for new treatments to encourage investment in equipment and training for the new procedure. Payments have decreased to an estimated $15,000 for the treatment next year, compared with $12,000 for conventional radiation.

Frank Vicini, chief of oncological services for Beaumont Hospitals in Royal Oak, Mich., is leading a national study on MammoSite's effectiveness in which he plans to study 4,300 patients. Results of the study are expected in 2015 (Abelson, New York Times, 10/27).

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