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Women who have had a lumpectomy to remove a breast tumor typically undergo six weeks of daily radiation to the whole breast, a method with 30 years of data supporting its effectiveness in preventing a recurrence of breast cancer.
But in the last decade, a shorter, alternative treatment called brachytherapy — in which radiation is delivered directly to the tumor site inside the breast — has become increasingly popular. Today as many as 10 percent of older women with breast cancer receive this type of radiation treatment, which only takes about five days.
But a study that looked at the records of more than 90,000 older breast cancer patients on Medicare, who were diagnosed between 2003 and 2007, found that women who opted for brachytherapy were twice as likely to need a mastectomy in the five years following treatment than were those who had traditional radiation.
The study was published May 2 in the Journal of the American Medical Association.
While the overwhelming majority of women in both groups were able to avoid a mastectomy, researchers still found that 3.95 percent of the women who chose the short-course brachytherapy subsequently had their breast removed, versus only 2.18 percent of those who had the longer, whole-breast radiation.
It's not clear why the rates differed, but it could mean the localized brachytherapy left cancer cells in other parts of the breast or failed to prevent new cancers from cropping up there, says Benjamin D. Smith, M.D., a radiation oncologist at University of Texas M.D. Anderson Cancer Center who was one of the study's authors.
The brachytherapy group also suffered more complications related to surgery and radiation than the traditional group, including infection (16.2 percent versus 10.3 percent), breast pain (14.6 percent versus 11.9 percent) and benign fatty lumps caused by tissue damage (8.3 percent versus 4.1 percent).
The study's results provide "a cautionary note," says Smith. "Different patients may weigh the data differently depending on their primary goals in treatment. For some, the convenience of brachytherapy may be very important."
One comforting note in the study: No matter which radiation treatment they chose, the great majority of women (nearly 90 percent) survived their bout of breast cancer five years after diagnosis.
A longer clinical trial comparing the two radiation approaches, sponsored by the National Cancer Institute and led by Frank Vicini, M.D., is currently ongoing. Researchers hope it will be able to clear up doubts about whether one treatment has better long-term results than the other, Vicini says.
After seven years of recruiting patients, the trial has uncovered no differences in radiation-related complications, he says. Longer-term outcomes will be available within a few years.
The question of which treatment is better, Vicini says, "will be answered beyond the shadow of a doubt."
Also of interest: Mammograms have high rate of false positives.