TUESDAY, Oct. 21, 2003 (HealthDayNews) -- When determining the type of radiation therapy following a lumpectomy, there's not enough long-term data to endorse partial-breast irradiation over whole-breast irradiation.
So says the author of a new study, which looked at some 2,700 women for a 15-year period who had whole-breast irradiation following a lumpectomy, to assess the cancer recurrence rate in the affected breast.
Whole-breast irradiation, the standard recommendation for women who've had a lumpectomy, requires radiation treatments of the entire breast where the cancer was found. The premise is that microscopic, undetected cancer cells might have escaped from the original tumor to other parts of the breast and the radiation will kill them, says study author Dr. Gary Freedman, a radiation oncologist at Philadelphia's Fox Chase Cancer Center.
"But partial-breast irradiation [where only the exact site of the cancer is irradiated] is a hot topic right now, and this study is a response to that," Freedman says.
Proponents of partial-breast irradiation cite the less-demanding aspects of the therapy -- it only takes one week of radiation instead of six -- and the belief that most recurrences of cancer appear at the site of the original tumor, rather than other parts of the breast.
But Freedman found that while that was true in the short term, by 15 years after the lumpectomies the recurrence rates at the original site of the cancer and other parts of the breast were nearly the same.
In his study, the rate of local recurrence of cancer was 3 percent after five years, compared to 1 percent in other parts of the same breast. After 10 years, the local recurrence rate was 6 percent, compared to 2 percent in the previously healthy part of the breast.
But after 15 years, the local recurrence rate was 9 percent, while the incidence of cancer in other parts of the same breast jumped to 7 percent.
Also after 15 years, the appearance of cancer in a woman's other breast, which had not been irradiated, was 14 percent. This could demonstrate the protective effect of irradiation in the original breast, Freedman says.
"We need to be cautious before we give up something with very good results," Freedman says of whole-breast irradiation.
Freedman presented his findings Oct. 21 at the American Society of Therapeutic Radiology and Oncology annual meeting in Salt Lake City.
Dr. Abram Recht, senior radiologist oncologist at Beth Israel Deaconess Medical Center in Boston, moderated the panel where Freedman presented his findings.
He says Freedman's study was very well done. But while there have been improvements in radiation treatments since the time of the start of Freedman's study, long-term data on partial-breast treatments are still lacking.
"Technically, things are different. We are better at picking out people who will do well with certain therapies, and the results of partial-breast irradiation today will be better," Recht says.
Also, he says, the findings on recurrences five years after partial-breast irradiation are "very impressive -- less than 5 percent."
"But there's very little long-term data, and still a lot of uncertainty -- who will do well, the technical parameters like the dose, how many treatments, how to integrate it with chemotherapy," Recht adds. "Can you legitimately offer this [partial-breast radiation]? I don't think so. It is not a standard of care."