Breast cancer survivors: keep heart health in mind

NEW YORK (Reuters Health) - Authors of a report released this week encourage women who survive breast cancer to address all of the modifiable risk factors they have for heart disease, because breast cancer therapy can damage the heart.

Thanks to new and improved therapies, death rates from breast cancer have fallen dramatically in recent years -- by nearly one quarter between 1990 and 2000; yet these improvements may ultimately be diminished by the heart-damaging effects of these live-saving therapies, the researchers warn in the Journal of the American College of Cardiology.

Most breast cancer therapies, including new treatments still being developed, increase a woman's long-term risk of heart disease. "We don't know exactly how large the added risk is, but we believe it's substantial," first author Dr. Lee W. Jones of Duke University in Durham, North Carolina, commented in a written statement.

Chemotherapy may damage the heart in as many as half of patients, diminishing the heart's pumping ability and increasing the risk of heart failure years later. Radiation therapy can cause scarring and tissue damage to the heart and lungs.

Herceptin, often given to women with high-risk genetic profiles, is also toxic to the heart, while experimental therapies that interfere with the growth of blood vessels that feed tumors can cause abnormal blood clotting, high blood pressure and reduced heart function.

Hormone therapies, such as tamoxifen, which reduce estrogen levels for a long time, may also be hard on the heart.

Women and their doctors need to focus not only on the immediate threat posed by breast cancer, but also on long-term cardiovascular health, the authors say. "There are millions of American women living with breast cancer," Dr. Pamela S. Douglas, co-author and chief of cardiology at Duke, said in a written statement. "It's important that they don't squander their second lease on life."

More than 200,000 largely middle-aged and older American women are diagnosed with breast cancer each year. At the time of diagnosis, these women are often already at heightened risk for heart trouble, having age-related risk factors for heart disease, such as high blood pressure. They may also lead a physically inactive lifestyle and be obese, two factors linked to breast cancer and heart disease.

Equally important, many women curb their level of physical activity during breast cancer therapy and gain weight as a result. Maintaining an active lifestyle is an important in women with breast cancer, the authors emphasize.

Exercise is likely to help women feel better during breast cancer treatment, and Jones thinks it might also improve blood flow to the tumor, thereby enhancing delivery of cancer drugs to their intended target.

Jones is currently investigating whether exercise can protect the heart against the damaging effects of chemotherapy, for example, by lowering blood pressure, reducing body weight and strengthening the heart's pumping action.

"If exercise can improve tumor outcomes while protecting the cardiovascular system, that would be a very important finding," the researcher said.

SOURCE: Journal of the American College of Cardiology, October 9, 2007.