TUESDAY, March 15, 2005 (HealthDay News) -- While radiation therapy can be a life saver for women with breast cancer, experts have long known it also increases their risk for heart disease -- especially when radiation is applied to the patient's left side, closest to the heart.
However, a new study shows a major decrease over the past 25 years in the risk of death from heart disease in patients receiving this therapy.
"These encouraging data suggest that advances in radiation techniques have been translated into substantial benefits for women with breast cancer," wrote researchers at the University of Texas M.D. Anderson Cancer Center in Houston in the March 16 issue of the Journal of the National Cancer Institute.
The study noted that in 2002, about 42 percent of breast cancer patients received radiation therapy after surgery to reduce the risk of tumor recurrence.
The researchers also point out that patients with left-sided breast cancer tend to receive a higher radiation dose to the nearby heart -- which may affect their risk of death from ischemic heart disease. However, modifications in radiation techniques over the past few decades have reduced these doses, they said.
The Houston team examined data from the U.S. National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program. They compared death from ischemic heart disease in women diagnosed with left-sided and right-sided breast cancer from 1973 to 1979, 1980 to 1984, and 1985 to 1989.
Between 1973 and 1979, women with left-sided tumors had a higher 15-year death rate from ischemic heart disease (13.1 percent) than women with right-sided tumors (10.2 percent). However, there was no statistically significant difference among women diagnosed with left-sided or right-sided breast cancer from 1980 to 1984 (9.4 percent vs. 8.7 percent) or from 1985 to 1989 (5.8 percent vs. 5.2 percent).
And they also note that any increased risk of death from ischemic heart disease in women with left-sided breast cancer was not apparent until late in the first 10 years of follow-up.
"Whether the risk of ischemic heart disease mortality resulting from radiotherapy has been entirely eliminated cannot be determined definitely from this study," the researchers contend. "Continued follow-up of the women diagnosed and treated in the late 1980s will be necessary to answer this question."
The U.S. National Cancer Institute has more about breast cancer treatments.