Radiation Cuts Risk of Breast Cancer Recurrence by Two-Thirds
May 18, 2000 -- Giving radiation therapy to women after they have surgery for early-stage breast cancer significantly reduces the risk that their cancer will return. But a new study of more than 20,000 women shows that radiotherapy may increase the risks of dying from something other than breast cancer 10 years or more after the treatment.
Experts caution that women should interpret the findings carefully, since the study involves data from trials done in the 1960s, '70s, and '80s, when radiation techniques were different than they are today. Most of the deaths from causes other than breast cancer are thought to be directly related to the older radiation techniques, in which the heart and surrounding structures in the chest and neck were exposed to the radiation beams.
Study co-author Rory Collins, MD, professor of medicine and epidemiology at the University of Oxford in England, tells WebMD that the positive message of the study is that it gives "absolutely clear" evidence that fewer women are now dying from breast cancer, as well as showing that radiation cuts the risk of the cancer's recurrence by two-thirds.
The study, published in the medical journal Lancet, found that in the first 10 years after treatment, 9% of the women who received radiation after surgery had a recurrence of cancer in the same area, compared with 27% of the women who did not receive radiation.
In the first two years after treatment, radiation had no apparent effect on deaths from causes other than breast cancer. But from that point on, the annual death rate was an average of 21% higher for all women who received radiotherapy.
Still, by keeping their cancer away, radiation made a positive difference for these women. In terms of overall survival, the groups were nearly equal: Women who got radiation had a 2% better survival rate 10 years after treatment than women who did not; by 20 years, the difference in death rates between the two groups was only 1.2%.
"In all of the women studied in these trials, there was no effect on overall survival," Collins tells WebMD. "There was a decrease in breast cancer death and an increase in non-breast-cancer death for all of the women."