Mayo Clinic researchers propose new strategies to combat side effects of common breast cancer drug treatment

Tuesday, February 05, 2008

SCOTTSDALE, Ariz. – There's little question that the drug Trastuzumab dramatically improves the survival rate of women afflicted with metastatic breast cancer — trials have shown it can cut the three-year risk of recurrence of cancer in half.

But research now indicates that the widely-used antibody also carries a significant risk of heart failure, especially when used in combination with certain other medications.

Following a thorough review of landmark trials, Mayo Clinic researchers have substantiated the potential dangers of Trastuzumab for certain patients. Their analysis indicates that symptomatic heart failure may occur in up to 4 percent of patients administered the drug.

"Breast cancer is the second most common form of cancer in women, and the leading cause of death," says Bijoy K. Khandheria, M.D., chair, Mayo Clinic Cardiovascular Services, researcher and co-investigator of the study. "Anticancer drugs like Trastuzumab have substantial benefits, but in some patients the anticancer drug cross-reacts with the heart muscle. Therefore, methods to detect and halt heart muscle damage is therefore urgently required."

In studying the treatment results of hundreds of patients, the Mayo team discovered that the risk of cardiotoxicity leading to heart failure was significantly increased when a Trastuzumab regimen included additional drugs known as anthracyclines. Anthracyclines are compounds used to treat a wide range of cancers. However, most patients who developed cardiotoxicity while receiving Trastuzumab therapy improved once its use was discontinued.

"Serial evaluation of subtle changes in heart muscle motion may enable early detection of heart muscle damage caused by Trastuzumab, much before symptoms of heart failure develop in these patients," says Partho P. Sengupta, M.D., lead author of the review who is investigating novel methods for imaging the heart's muscle mechanics under Dr Khandheria's mentorship.

"These findings will allow physicians to utilize the proven effectiveness of Trastuzumab but combat the potential danger of symptomatic heart failure," said Dr. Khandheria.

Other Mayo researchers participating in the project were Donald W. Northfelt, M.D.; Federico Gentile, M.D. and Jose L. Zamorano, M.D. The findings were published in Mayo Clinic Proceedings, February 2008.

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Mayo Clinic Cancer Center is one of only 39 U.S. medical centers that have been named as a National Cancer Institute (NCI) Comprehensive Cancer Center. To receive this designation, an institution must meet rigorous standards demonstrating scientific excellence and the ability to integrate diverse research approaches to address the problem of cancer. Mayo Clinic Cancer Center is the only national, multi-site center with the NCI's Comprehensive Cancer Center designation. In Arizona, Mayo's clinical and research experts work together to address the complex needs of cancer patients, with a dedication to understanding the biology of cancer; discovering new ways to predict, prevent, diagnose and treat cancer; and transforming the quality of life for cancer patients today and in the future.

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