IOWA CITY, Iowa -- A University of Iowa Health Care treatment using high-dose chemotherapy followed by a bone marrow transplant may be more effective in fighting advanced breast cancer than standard treatment approaches -- despite recent reports of conflicting results from similar strategies tested elsewhere.
In the just-released issue of the journal Biology of Blood and Marrow Transplantation, UI researchers suggest that a four-drug, high-dose chemotherapy treatment along with a bone marrow transplant may improve survival for some women with stage IV breast cancer -- cancer that has spread beyond the breast.
"We have women who we treated with a bone marrow transplant up to 10 years ago who are still alive and free of cancer," said Roger Gingrich, M.D., Ph.D., UI professor of internal medicine and director of the Adult Bone Marrow Transplant Program at the UI Hospitals and Clinics. "We think it is very important for women with breast cancer to continue to carefully consider this treatment approach."
From May 1988 through May 1997, UI physicians treated 158 women with stage IV breast cancer using the four-drug, high-dose chemotherapy and bone marrow transplant strategy. Preliminary results indicate an overall survival rate of 38 percent.
At an American Society of Clinical Oncology (ASCO) meeting last week in Atlanta, researchers presented four studies that showed women with very risky or advanced breast cancer statistically did no better with the high-dose chemotherapy and bone marrow transplant treatment than those who received only low-dose chemotherapy. A fifth, relatively small study indicated that the high-dose chemotherapy/bone marrow transplant approach might work better. Each of the studies involved different drugs and doses.
In the two studies presented at the meeting that involved patients with chemotherapy-responsive stage IV breast cancer, the projected survival rates using the high-dose chemotherapy/transplant treatment were 32 percent and 30 percent after three years. In the UI study, the projected survival rates for patients with chemotherapy-responsive stage IV breast cancer using the high-dose chemotherapy/transplant treatment was 53 percent from five to more than nine years.
"The reason our study shows different results may be related to our different approach," Gingrich said. "The key difference between our technique and those tested elsewhere is that we have chosen to use a more intensive pre-transplant regimen of chemotherapy and radiation. Our treatment involves a four-drug regimen and is 35 to 40 percent more intensive than the regimens used in the recently reported studies. We administer our regimen in a highly specialized transplant unit, not in the outpatient setting. It is associated with an 11 percent mortality rate, but the payoff may be a higher proportion of women surviving without cancer."
The UI strategy involved treating the women with a combination of the drugs cisplatin, etoposide, thiotepa and cyclophosphamide followed by blood or marrow stem cell transplantation. The studies presented at the ASCO meeting involved combinations of two or three drugs at a time.
"We're not saying that the less intensive approach is wrong or that the more intensive regimen is the right way, or the only way," Gingrich said. "What we are saying is that we need more research. This field is so new that the definitive study on the best approach has not been done yet."
An estimated 12,000 women with breast cancer in the United States have undergone high-dose chemotherapy/bone marrow transplant procedures since the mid-1980s. The transplants are necessary following the high-dose chemotherapy to replace the blood cell-producing marrow that the drugs destroy. High-dose chemotherapy and/or radiation with bone marrow transplants is standard treatment in some circumstances for some malignancies, including acute leukemia, chronic myelogenous leukemia, neuroblastoma, lymphoma and myelodysplastic syndrome.
The five studies presented at the ASCO meeting were all randomized, controlled, phase III clinical trials, which directly compared one cancer treatment to another -- in this case, high-dose chemotherapy and bone marrow transplants to standard doses of chemotherapy. The UI study was a phase II clinical trial designed to test the feasibility of a novel therapy. In a phase II trial, researchers do not compare treatments directly but rather compare the new strategy to historical data from accepted treatment.
"While the papers presented at the ASCO meeting may have cast some doubt about the usefulness of high-dose chemotherapy for patients with breast cancer, it is too early to discard this approach," Gingrich said. "All we can be sure of is that some of the first organized comparative trials to test this approach failed, and this is certainly not the first time this has happened in the field of oncology.
"Within the high-dose chemotherapy range, therapies of lower intensity do not appear effective," Gingrich said. "We now need to examine whether an approach such as ours, when tested in a randomized, comparative fashion, will be beneficial. We certainly think it will."