Breast Cancer Drugs Work Best When Given Together, Research Shows
WebMD Health News
Reviewed By Louise Chang, MD
Dec. 15, 2009 (San Antonio) -- In findings that have been eagerly awaited by women with breast cancer and their doctors, researchers report that the breast cancer drug Herceptin should be given at the same time as chemotherapy, not after chemotherapy is concluded.
"Giving the drugs concurrently instead of sequentially results in an additional 8,000 women with HER2-positive cancer in the U.S. being alive and without disease each year," Edith Perez, MD, of the Mayo Clinic tells WebMD.
About 20% of breast cancer patients have HER2-positive cancers -- tumors that have too much of a type of the HER2 protein. Herceptin binds to and blocks HER2 receptors that appear on the surface of some breast cancer cells.
Compared with chemo alone, giving Herceptin after chemo cuts the chance that cancer will come back within five years by about one-third, Perez says.
Giving Herceptin and chemo together slashes the risk of recurrence by an additional one-fourth, she says. "It's a huge gain."
Both the concurrent and sequential methods of giving the drugs are approved by the FDA, and most U.S. doctors already give the drugs together, says Claudine Isaacs, MD, a breast cancer specialist at the Georgetown Lombardi Comprehensive Cancer Center in Washington, D.C.
But in Europe and elsewhere, doctors tend to give Herceptin after chemotherapy has ended, she says. As a result, the findings have been eagerly awaited, Isaacs says.
She moderated a news briefing at which the results were presented at the annual San Antonio Breast Cancer Symposium.
Giving Herceptin, Chemo Together Helps Breast Cancer Patients
The study involved 3,133 women with HER2-positive tumors. They were given one of three treatments: three chemo drugs alone; three chemo drugs with Herceptin given at the same time as the third chemo drug; or three chemo drugs followed by Herceptin.
By five years later, both Herceptin strategies beat out chemo alone in terms of the number of women who were alive and free of their disease. But women given Herceptin and chemo together fared the best, Perez says.
The results showed that:
- 71.9% of women given chemo alone were alive and free of cancer.
- 80.1% of women given chemo followed by Herceptin were alive and free of cancer.
- 84.2% of women given chemo plus Herceptin started at the same time as the third chemo drug were alive and free of cancer.
Perez says she believes the drugs act synergistically to improve outcomes.
Heart problems, a known side effect of Herceptin, occurred in about 3% of women in either Herceptin group vs. less than 1% in the chemo-only group.
"But most of these [heart problems] are transient in nature and manageable with medical therapy," she says. "Cancer recurrence is the big problem you want to avoid."
The National Cancer Institute, the Breast Cancer Research Foundation, and Genentech, which makes Herceptin, funded the study.
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SOURCES: 32nd Annual San Antonio Breast Cancer Symposium, San Antonio, Dec. 9-13, 2009.
Edith A. Perez, MD, professor of medicine, division of hematology/oncology, Mayo Clinic, Jacksonville, Fla.
Claudine Isaacs, MD, Georgetown Lombardi Comprehensive Cancer Center, Washington, D.C.
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