SUNDAY, Nov. 16, 2003 (HealthDayNews) -- 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.
This suggests that whole-breast irradiation must remain the standard -- at least for now, he says.
"The burden of proof is on the people who want to treat less than the whole breast," says Freedman.
Nationwide, Freedman says, "a handful of experts have been believers and major proponents" of partial-breast irradiation. But even though the device has been approved by the FDA, partial-breast irradiation is still considered experimental, the American Cancer Society says.
The FDA approved the device based on data from 25 women at eight medical centers who had it implanted after a lumpectomy, the cancer society says.
The device uses a kind of radiation called brachytherapy, in which radioactive seeds or pellets are placed in the area being treated. It is implanted into the breast at the lumpectomy site. Then the device's balloon is inflated and the radioactive source is inserted through a catheter.
Dr. Herman Kattlove, a medical oncologist and spokesman for the American Cancer Society, also counsels patience until more is known about partial-breast irradiation's long-term effectiveness.
"We're concerned that [partial-breast irradiation] hasn't been proven," he says. "It's too early to tell" if it will bear out as a treatment as effective as whole-breast irradiation. "I would recommend caution," he says.
"We're awaiting results of [the ongoing] clinical trials," he adds. "We need to have that data."
Freedman concurs. "Standard treatment is certainly [irradiating] the whole breast," he says. If women want to try the partial-breast irradiation treatment, he adds, they should do it in an approved clinical trial.
"We're not against clinical research," Freedman says. "What I don't like is, women are being given this [treatment] outside of clinical studies."
This year, more than 200,000 people in the United States will get a new diagnosis of breast cancer, according to American Cancer Society estimates, and more than 40,000 are expected to die from the disease.