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Breast Cancer Patients Should Monitor Heart Risks
08.14.06, 12:00 AM ET MONDAY, Aug. 14 (HealthDay News) -- Heart problems remain a real but largely manageable problem for women undergoing different treatments for breast cancer.
Two studies appearing online Aug. 14 in the
Journal of Clinical Oncology underscore the need to carefully monitor patients taking the drug Herceptin as well as those undergoing radiation therapy.
The first study found that women receiving long-term Herceptin have a risk of heart problems, but that the risk is reversible.
"We looked at long-term use of Hercpetin and found that, even though cardiac toxicity was considerable, the side effects can be successfully treated, which was not clearly known," said Dr. Francisco Esteva, senior author of the paper and an associate professor of medicine at M.D. Anderson Cancer Center in Houston. "In many patients who were responding to the treatment, the cardiac toxicity was reversible. It is something that can be managed and the patients can go back on Hercptin -- and many of them did."
Some 20 percent to 25 percent of breast cancers have abnormally high levels of the HER2/neu receptor and, as a result, are generally more aggressive. Herceptin (trastuzumab) blocks activity of the receptor by binding to the part of the receptor outside the cell. The drug has radically changed the prognosis for women with this type of breast cancer, especially when used in combination with chemotherapy. The drug is now standard therapy for those with HER2-positive metastatic breast cancer.
This study focused on 218 patients with metastatic breast cancer who had been given Herceptin for at least one year (median time was 21.3 months). Of those, 173 could be assessed for cardiac problems. The median follow-up was 32.6 months.
Twenty-eight percent of the patients experienced a cardiac event, many of which caused no symptoms and all of which were reversible. One patient died of congestive heart failure.
"I find the drug in certain situations to be simply amazing, but it does have a dark side in terms of its heart failure," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La. "The good news is that most of the time, when heart failure is recognized, the drug is withdrawn, the woman is treated and, in many cases, depending on the clinical situation, Herceptin can be reinstituted."
"It's prudent to be very careful in administering these drugs," he added.
"We advise every patient to have a baseline cardiac assessment before starting treatment and be followed by a cardiologist who is familiar with this," Esteva added.
The second study found that women with early stage breast cancer who received radiation on the left side of the chest were more likely to develop heart disease over the next 20 years than women who received radiation on the right side of the chest. But even those women who received left-sided radiation did not have an increased risk of death from heart-related problems.
The University of Pennsylvania researchers compared the incidence of heart disease in 477 women who had had early stage breast cancer on the right side and 484 women who had had early stage breast cancer on the left side. All had been treated with current radiation techniques between 1977 and 1994 and were followed for a median of 12 years.
At 20 years, 6.4 percent of patients with left-sided cancer had died from heart-related problems, versus 3.6 percent of those with right-sided cancer.
One-quarter of women who received radiation on the left side of the chest developed coronary artery disease, versus 10 percent of those in the right-sided group. Also, 15 percent of those in the left group had a heart attack, compared with only 5 percent in the other group. Women who had high blood pressure before they started therapy on the left side had an even higher risk of heart disease.
Because radiation is continually getting more focused, it's likely that this risk will be reduced even further in the future, experts said.
"The use of current radiation techniques has really gone a long way to eliminating the risk of cardiac toxicity," Brooks said. "The chances of having side effects from radiation for left-sided lesions is small, but it's real."
Women should reduce and preferably eliminate other modifiable risk factors for heart disease such as high blood pressure, obesity and smoking.
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