Popular breast cancer treatment increases risk of mastectomy
Brachytherapy is an increasingly popular option for women with early-stage breast cancer. After a lumpectomy to remove abnormal tissue, doctors insert either a series of tubes or a catheter attached to a small balloon into the breast. A radioactive source is then delivered to the surgical site, where it can kill off any remaining cancer cells within about 1 centimeter. After five days of treatment, the tubes or catheter can be removed.
As this site from UCLA’s Department of Radiation Oncology explains, brachytherapy allows doctors to irradiate the breast “from the inside out,” unlike the traditional method of applying radiation to the entire breast with an external beam. But is it actually better for patients?
The best way to answer this question is to conduct a clinical trial in which some women get brachytherapy following lumpectomy and others get whole breast radiation, then tracking both groups for several years to see which fares better. One such trial – sponsored by the National Cancer Institute – is underway, but researchers won’t be done enrolling patients until later this year, and final results are still years away.
In the meantime, a group of researchers from the University of Texas M.D. Anderson Cancer Center in Houston and the University of Chicago decided to compare women who had already selected one option or the other and see how they stacked up against each other. Their surprising results will be published in Wednesday’s edition of the Journal of the American Medical Assn.
The researcher team used data compiled by Medicare, so their patient population was large – 92,735 women treated for breast cancer between 2003 and 2007. The average age for these women was nearly 75, and they were tracked for an average of about three years after they began their radiation therapy.
One thing the numbers clearly showed was the growing appeal of brachytherapy. In 2003, only 3.5% of women on Medicare opted for this treatment, but by 2007 that figure had risen to 12.5%, according to the study.
Some of them may have regretted that decision. In the five years after brachytherapy, 3.95% of these women went on to have a mastectomy, compared with only 2.18% of women who opted for whole breast radiation. After controlling for various demographic and other factors, the researchers still found that women who had brachytherapy were 2.19 times more likely to have their breast removed.
Overall, the researchers calculated that “for every 56 women treated with breast brachytherapy, 1 woman was harmed with unnecessary mastectomy,” they wrote.
Regardless, the overwhelming majority of women in both groups were able to preserve their breasts. But the need for a mastectomy wasn’t the only thing that was worse for the brachytherapy group. These women also turned out to be more prone to postoperative complications, including infections. In the first year after lumpectomy, 28% of women in the brachytherapy group had a complication, compared with 17% of women in the whole breast irradiation group, the researchers found.
There were also more complications from radiation. In the five years after their treatments began, 25% of women who got brachytherapy reported some sort of complication, versus 19% of women who got whole breast irradiation. These complications included breast pain, fat necrosis and rib fracture, according to the study.
The researchers mined the data in search of particular subgroups of women who may have benefitted from brachytherapy despite the increased risks, but they came up empty-handed.
The best news is that most women survived their bouts of breast cancer no matter which type of radiation treatment they chose. Among the brachytherapy women, 88% were still alive after five years, along with 87% of those who opted for whole breast radiation. (The women who passed away may have died of something other than breast cancer.) The difference was deemed statistically insignificant after the researchers took age, education level and other factors into account.
You can read the study online here.
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