MammoSite: FDA-Approved, But Does It Work?

PJ Hamel Health Guide
  • An Oct. 27 New York Times article on the relatively new MammoSite radiation therapy for breast cancer patients includes a sentence that I find starkly chilling in its implications:

    “The FDA says it did require a label warning that the system had not been shown to be a substitute for conventional radiation.”

    In other words, the FDA approved a device for breast cancer treatment that no one’s sure really works.

    About 250,000 American women are diagnosed with breast cancer every year, and about 200,000 are candidates for radiation: either in conjunction with breast-conservation surgery (lumpectomy), or mastectomy. The gold standard of treatment for decades has been conventional radiation: radiation beams delivered via an external device, passing through the skin to the site of the excised tumor. The 5-year rate of local recurrence for this type of radiation is 3% or less. This information is based on decades’ worth of data.

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    In 2002, the FDA approved a new device for delivering radiation: MammoSite, a product that shoots radioactive seeds into the breast, via catheter, directly to the site of the excised tumor. These seeds are contained in a balloon, and deliver radiation for 5 to 10 minutes at a time, twice a day, for 5 consecutive days. And that’s it: end of treatment.

    Sounds great, doesn’t it? Conventional radiation is administered 5 days a week for 5 to 6 weeks. Which means you HAVE to show up for treatment every day for more than a month. If you live a long way from the hospital or cancer center; if your employer isn’t flexible; if you’re a mom with young kids at home… this is a punishing schedule. Many women choose to forego radiation simply because the process for its delivery is too challenging.

    So in steps MammoSite. One week? Most women can handle that. The FDA approves it; Medicare and insurance cover it; what’s not to like?

    Well, how about the fact that it’s such a new device, the evidence submitted for FDA approval involved just 25 women? And how about the fact that FDA approval of MammoSite means simply that it does what it says: it delivers radiation. Period.

    But does MammoSite work as well as standard radiation? Does it actually prevent cancer recurrence?

    The answer is, we simply don’t know. Not yet. Not till MammoSite has accumulated the years’ worth of data that already supports the proven use of conventional radiation.

    Radiation oncologists are divided over the use of MammoSite. Some believe its track record thus far—with the limited data available, it appears to be as effective as conventional radiation—will play out over the long haul, and they routinely recommend MammoSite to their patients. Others offer MammoSite as an option, with the caveat that it’s still experimental.

    And to add another twist, the Times reports that critics within the medical community link MammoSite’s popularity among certain providers to its larger financial payoff. The Medicare reimbursement is higher for MammoSite vs. radiation. And surgeons can charge several thousand dollars to insert the catheter for its delivery, where conventional radiation doesn’t involve any surgery. The inference is that money may be one of the drivers here. 

  • Dr. Frank Vicini, director of oncological services at Beaumont Hospital in Royal Oaks, Mich., is directing the first long-term national study involving MammoSite. Despite being a leading proponent of its use, Dr. Vicini cautions that “We have to make sure patients know we don’t have 30-year data. We simply don’t.” The study, which will conclude in 2015, involves 4,300 women.

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    In the meantime, if you’re offered MammoSite as an alternative to conventional radiation, be sure you understand what you’re choosing. Based on the stress and potential expense of 6 weeks of treatment vs. 5 days, you may very well decide that this new kid on the block is right for you. But will it keep your cancer from recurring as effectively as that 6-week treatment will?

    No one knows.

Published On: November 09, 2008