Quest for less-toxic drugs
More and more doctors are looking to replace old-line cancer drugs that have known toxic heart effects with ones that might work as well but without the heart problems, said Jim Stewart, an oncologist at the University of Wisconsin Hospital and Clinics in Madison.
“We have to assume that a woman with breast cancer will be alive 20 or 30 years later,” said Stewart, also a professor of medicine at UW.
Indeed, since aging is an independent risk factor for heart disease, longer survival for breast cancer patients who also might have been exposed to heart-damaging drugs is likely to mean more cases of cardiovascular disease in the years to come.
“It’s a reflection of success,” Stewart said. “They are surviving long enough to be at risk.”
In September, a study of 43,338 older women treated for breast cancer between 1992 and 2002 found a 26% higher rate of subsequent heart failure in those treated with anthracycline cancer drugs compared with non-anthracycline drugs. Anthracyclines are a class of drugs used on a variety of cancers and still are a mainstay in breast cancer treatment. The research was published in the Journal of Clinical Oncology.
Although anthracycline drugs are of more concern, most of the drugs used to treat breast cancer pose some short-term and long-term potential for heart complications, doctors say.
Issues with radiation
In March, a study in the Journal of the National Cancer Institute raised concerns about radiation therapy.
The study noted that doctors have modified radiation therapy since the 1970s so that it is less harmful to the heart. However, it still can have an adverse effect on the heart, according to the study.
The study involved 1,979 women who underwent radiation therapy of the internal mammary chain lymph nodes. They had higher rates of heart failure and heart valve dysfunction than those who received only breast irradiation. In addition, women who received radiation therapy and who smoked were three times more likely to have a heart attack.
At some hospitals, oncologists now are using non-anthracycline drugs in selected breast cancer patients who already have heart problems that might be worsened by the drugs.
John Charlson, an oncologist at Froedtert and an assistant professor of medicine at the Medical College, pointed to recent preliminary research suggesting that another class of cancer drugs called taxanes might be less toxic to the heart than anthracyclines. As a result of that research, about 10% of breast cancer patients at Froedtert now are treated with the new drugs while doctors wait for more research to see if the drugs can be used in larger groups of breast cancer patients, he said.
Already, some Internet-savvy patients are asking about other drug options because of concerns about heart damage, he said.
A second chance at life
The other good news is that by lifestyle changes and controlling other cardiovascular risk factors, cancer patients might be able to reduce their heart risk significantly, said Pamela Douglas, co-author of the paper last month in the Journal of the American College of Cardiology.
That includes maintaining a healthy weight, exercising and being vigilant about controlling their blood pressure and cholesterol, said Douglas, a professor of cardiology at Duke University Medical Center in Durham, N.C.
Indeed, she said the success of breast cancer treatment means doctors increasingly are telling patients two things: “Congratulations, you’ve been cured of cancer. Since you’ve been given a second chance at life, here’s what you need to do to optimize it.”
In addition to radiation therapy and anthracycline drugs, the journal article noted other heart concerns associated with breast cancer treatment:
–Another common breast cancer drug, Herceptin, is associated with a 2% to 4.1% increased incidence of heart failure.
–Although endocrine therapy drugs such as tamoxifen are not known to be damaging to the heart (and might actually be beneficial for the heart), those drugs cause a small increase in formation of clots.
–Promising new drugs that interfere with the blood supply to tumors might also increase the risk of clots, reduce the pumping ability of the heart and worsen high blood pressure.
–At the same time, physical inactivity and weight gain can worsen heart problems for cancer patients. Some research suggests that breast cancer patients decrease their physical activity by two hours a week. Another study found that more than 70% of patients increased their body weight by 5 to 14 pounds.
Other patients affected
It’s not just breast cancer patients who are at risk.
In 1999, Sue Northey of Franklin underwent extensive radiation therapy for Hodgkin’s disease, treatment that would damage her heart a few years later.
Northey, 49, said she doesn’t remember being told about the potential for heart problems, although things were such a blur and she was so worried about the cancer that any warnings might have slipped her mind.
“How would I have made a different decision?” she added. “It was choosing between life and death, and I chose life.”
Her cancer has been in complete remission since 1999, but a few years ago the first signs of other problems started cropping up.
She began feeling short of breath in 2004.
“By the end I couldn’t even walk up a flight of stairs,” said Northey, an advertising executive. “I just didn’t have any life anymore.”
Tests showed she had a condition known as constrictive pericarditis, a condition in which the pericardium, the sac around the heart, becomes inflamed, calcified and thick. A normal pericardium is about 1 to 3 millimeters thick; Northey’s was between 5 and 8 millimeters.
In July, Northey underwent a five-hour heart operation at Froedtert to remove scar tissue and part of the pericardium.
Her shortness of breath has gone away, and she easily can walk for a half-hour on the treadmill.
“I have a new lease on life,” she said. “I feel the best I’ve felt in a decade.”
Her case, though, is an example of how cancer patients should be especially vigilant about taking care of their hearts because of the problems that can occur long after treatment, said Northey’s doctor, Lee Biblo, a cardiologist at Froedtert.
“It’s like a chess game where you’re trying to stay five or 10 years ahead,” said Biblo, vice chairman of medicine at the Medical College. “In women, heart disease is still the number one killer.”
Source: By John Fauber, Milwaukee Journal Sentinel
cancervisa
Cancer Visa Blog 
Leave a comment