It's called partial-breast irradiation, and proponents see it as a promising alternative treatment for breast cancer patients who've just had a lumpectomy.
Thousands of women have already sought out the therapy, which requires just one week or less of radiation after breast cancer is diagnosed, instead of the six or seven weeks required for whole-breast irradiation.
But its long-term benefits remain unproven, some experts caution.
That's why the National Cancer Institute has launched a major study of this experimental therapy this fall, to offer women sound guidance based on years of observation.
Dr. Gary Freedman is a radiation oncologist at Fox Chase Cancer Center in Philadelphia who is urging a cautious approach. He says some studies looking at the benefits of partial-breast irradiation five years after treatment have produced acceptable results. But, he adds, "five-year results aren't long enough to say, 'This is a standard alternative.'"
Interest in partial-breast irradiation heightened after the U.S. Food and Drug Administration (FDA) approved a new radiation device in 2002. Bearing radioactive seeds, it's implanted after a lumpectomy into the site from which the tumor has been removed and then delivers radiation to that area only, not the entire breast.
The therapy is proving popular with women who find the short timetable far more convenient.
Partial-breast irradiation is based on the idea that most recurrences of cancer appear at the site of the original tumor, not other parts of the same breast.
Whole-breast irradiation works by treating the entire breast with radiation, to prevent undetected cancer cells that might have escaped from the original tumor from spreading to other parts of the same breast.
Freedman presented a study last month at the annual meeting of the American Society of Therapeutic Radiology and Oncology that compared whole-breast to partial-breast irradiation.
He reported that the follow-up data on whole-breast irradiation is much longer than that for the newer technique. His research also showed that 15 years after a lumpectomy, the cancer recurrence rates were nearly the same at both the original tumor site as well as other parts of the breast.
Freedman evaluated 2,700 women who had whole-breast irradiation, to assess the cancer recurrence rate in that breast. After five years, the recurrence rate at the original tumor site was 3 percent, while it was 1 percent in other parts of the same breast. After 10 years, it was 6 percent at the original site and 2 percent in other parts of the same breast. But after 15 years, the recurrence rates were 9 percent at the initial cancer site and 7 percent in other parts of the same breast.