They said the finding, to be presented next month to a meeting of the American Society of Clinical Oncology, may save many women and their doctors a lot of trouble, not to mention the costs of radiation.
This study confirms that for older women with early stage breast cancer, lumpectomy without radiation is a viable alternative, and tamoxifen may replace the need for radiation, said Dr. Kevin Hughes of Massachusetts General Hospital in Boston, who led the study.
Hughes and colleagues now have 12 years of data on 636 women aged 70 or older who had stage I breast cancer, the easy-to-cure type that has not spread and that is so-called estrogen receptor-positive.
The women had the tumors removed in an operation called a lumpectomy. Half got radiation treatment and then took five years of tamoxifen, a pill that has been shown to cut in half the risk that breast cancer will return.
The other half went straight to tamoxifen.
Twelve years later, 12 women who got radiation had died from their breast cancer, compared to eight who got tamoxifen only, Hughes told reporters in a telephone briefing. Many of the women died, but more than 95 percent died from something other than breast cancer.
We did find that radiation did have some benefits in terms of in-breast recurrences but those benefits are relatively small, Hughes said.
He said 26 women who did not have radiation got new tumors in the same breast, compared to six women who had radiation. Those women could have the new tumors removed and then have radiation later.
ASCO president Dr. Douglas Blayney said the work showed that publicly funded, academic research can help patients in ways that research done by the pharmaceutical industry and device makers would not. This is the kind of study that would not be done ... if we relied on industry, Blayney said.
I think that many women and their physicians currently don't do radiation. This gives us comfort in the fact that this is a reasonable course of action, Blayney said.