High-dose chemotherapy may increase breast cancer survival
May 28, 1999
Web posted at: 11:12 AM EDT (1512 GMT)
By Laura Lane
An intensive form of chemotherapy treatment may improve chances of survival for breast cancer patients in more advanced stages of the disease, two independent studies show. One of the studies is among the largest ever to examine the therapy's effectiveness in treating breast cancer.
The study results should pave the way to better treatment options for breast cancer patients. Breast cancer is the third leading cause of cancer deaths in the country. With more than 175,000 women diagnosed with the disease every year, breast cancer is the most prevalent kind of cancer among women.
Study researchers tested the power of high-dose chemotherapy, with doses five to 30 times higher than usual, to eradicate disease that had already spread to the lymph nodes. In most of these advanced cases, standard chemotherapy is ineffective in ridding the body of cancer, which usually returns after a period of time, said Dr. William Peters, lead author of the larger study and president and chief executive officer of Karmanos Cancer Institute in Detroit, Michigan.
"We're very encouraged that these patients are doing better than what we're seeing in standard therapy," Peters said. "The survival is better than what we've ever seen."
The studies were discussed during the 35th annual conference of the American Society of Clinical Oncologists in Atlanta, Georgia, in May.
Treatment under examination
In the smaller study, researchers at the University of Witwaterstand Medical School in South Africa compared the survival rate among 154 women with advanced breast cancer receiving either standard or high-dose chemotherapy.
Because high doses of chemotherapy are extremely toxic, patients must receive a bone marrow transplant after chemotherapy. Bone marrow contains cells that can regenerate vital blood cells and immune system cells that are killed by lethal amounts of chemotherapy.
Women who received the high-dose chemotherapy were far less likely to experience a relapse (a return of the cancer) and were far more likely to survive for five years than women who received the standard dose.
Five years after treatment, 25 percent of high-dose patients experienced a relapse, compared to 66 percent of standard-dose patients, the researchers revealed at the conference. In addition, 17 percent of high-dose patients were no longer alive five years after treatment, compared to 35 percent among standard-dose patients.
A closer examination
The larger study, which included 783 women, placed the high-dose treatment under tighter scrutiny, Peters said. The researchers compared the high-dose therapy to one using an intermediate dose, which was higher than the standard dose.
Women who received the high-dose chemotherapy, followed by a bone marrow transplant, were 34 percent less likely to develop a relapse three years later than intermediate-dose women. Three years after treatment, 12 percent more high-dose women survived without incident than intermediate-dose women, Peters said at the conference.
A second look
Discussion of high-dose chemotherapy also included the results of three other studies, which failed to show that the therapy is effective in improving the prognosis for breast cancer patients. However, the results are still preliminary, said Dr. Robert Collins, director of bone marrow transplantation at the University of Texas Southwestern Medical Center at Dallas.
"There still might be some benefit to high-dose chemotherapy," Collins said.
In a few years, women who received the therapy could have better survival and relapse rates than women who received lower doses of chemotherapy, he explained. For example, within the next year, low-dose women could experience relapse, while high-dose women continue to survive without relapse.
Peters is optimistic, saying that data from his study already shows that women who received high-dose chemotherapy have a "strong trend toward event-free survival, including relapse."
High-dose chemotherapy, followed by bone marrow transplant, has been used to treat leukemia patients for more than 20 years. Because of its success in treating leukemia and similar cancers, physicians began to try the therapy on breast cancer patients. The new studies will offer these physicians greater insight into the efficacy of the treatment, which previously lacked substantial research data.
Peters said that continued research could help find ways to make chemotherapy less toxic and more effective.
Copyright 1999 by WebMD, Inc. All rights reserved.
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