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Study Questions Guidelines on Radiation for Older Breast Cancer Patients
Current advisory says no to radiation post-lumpectomy, but new data suggest otherwise
Monday, August 13, 2012
This suggests that current guidelines recommending that these older patients not have radiation need to be updated, stated the authors of the study, published online Aug. 13 in the journal Cancer.
"Overall in this group of women, radiation was associated with a decrease in mastectomy," said study senior author Dr. Benjamin Smith, an assistant professor of radiation therapy at the University of Texas MD Anderson Cancer Center, in Houston. "The absolute decrease was small but it was certainly measurable."
The current treatment guidelines recommend that older women with early, estrogen receptor-positive breast cancer (a cancer that responds to estrogen) that has not spread to the lymph nodes undergo a lumpectomy to remove the tumor, followed by hormonal therapy but no radiation.
The guidelines were largely based on a 2004 study that concluded that radiation in this group of women only slightly decreased the odds of cancer recurring compared to receiving the estrogen-blocking drug tamoxifen alone.
The risk of a recurrence is very low in older women compared to younger women, for whom radiation following lumpectomy is more routinely recommended.
In the new study, the authors reviewed the medical records of more than 7,400 women aged 70 to 79 who had undergone a lumpectomy for early-stage, estrogen receptor-positive breast cancer between 1992 and 2002.
Almost 90 percent of these women had received radiation after surgery.
After a follow-up period of 10 years, 6.3 percent of women who did not get radiation needed a mastectomy versus only 3.2 percent of women who had received radiation.
It's not clear why these women had to have a mastectomy but the most plausible reason is that the cancer recurred, the authors stated.
Certain women seemed to benefit more from radiation than others, namely those with high-grade (aggressive) tumors, Smith said.
"These are highly aggressive-looking cell types," said Dr. Philip Bonanno, director of the breast program at Northern Westchester Hospital in Mt. Kisco, N.Y. "This is a tumor that we know is going to be a bad actor given enough time."
Radiation was not particularly beneficial in patients who were 75 and older who did not have high-grade tumors and whose cancer had not spread to the lymph nodes, he added.
The study did not assess survival rates.
The study did have some limitations, namely that it was not designed to assess cause and effect, nor did it have information on which women took hormonal therapy, which can reduce the risk of a recurrence by about 50 percent.
And radiation itself has drawbacks, including the inconvenience of having to go to a medical facility every weekday for six weeks (usually), as well as fatigue and breast pain.
It's unclear if the findings will be practice changing, Smith said.
At the very least, he said, the paper should help clarify which older patients would benefit the most from radiation.
"I view this paper as adding a very nice layer of nuance on top of those guidelines," he said. "In our practice group, we'll be more enthusiastic about radiation in high-grade tumors and less enthusiastic in low-grade tumors, particularly in older women."
"Women over 75 years of age are not all the same and neither are their cancers," Bonanno agreed.
The study was partially funded by Varian Medical Systems, which makes radiation equipment. Other funding came from the U.S. National Cancer Institute and the U.S. Department of Health and Human Services.
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