Breast Cancer Transplant Trials Continue to Show No Benefit
The final analysis of data from one of the major U.S. trials of high-dose chemotherapy with stem cell transplant for breast cancer shows that it holds no survival advantage over intermediate-dose therapy. The findings from the trial, known as CALGB 9082 (see a summary of the protocol), were presented today at the annual meeting of the American Society of Clinical Oncology (ASCO) in San Francisco.
CALGB 9082 is one of five randomized transplant trials in the United States designed to show whether high-dose chemotherapy with transplant could increase survival in breast cancer. The trial tested the therapy in patients with 10 or more involved lymph nodes (Stage II or IIIa), comparing a high-dose regimen with transplant to intermediate-dose therapy. The "intermediate" doses were higher than those used in standard chemotherapy and were combined with G-CSF (granulocyte colony stimulating factor) to help patients regain normal blood counts.
 With about half of the patients now followed for 5.5 years, relapse rates were virtually the same in the two groups, said principal investigator William Peters, M.D., of the Barbara Ann Karmanos Cancer Institute in Detroit, Mich. Peters reported that 61 percent of patients who received the high-dose therapy had not yet relapsed compared to 60 percent of those who received intermediate-dose chemotherapy.
Peters also reported that 32 patients who received the high-dose chemotherapy had died as a result of the treatment. There were no treatment-related deaths in the intermediate-dose group.
In women with fewer involved nodes and in younger women -- those under age 45 -- overall survival appeared somewhat better in the high-dose group, Peters said. Nonetheless, he concluded that the treatment "remains a viable treatment option" in younger women within the context of a clinical trial.
However, early results from two other trials reported at the meeting add to the growing evidence that high-dose regimens do not increase breast cancer survival and so may not be worth the additional toxic effects. The first data from a Canadian trial in metastatic breast cancer show no difference in overall survival between 110 women who received high-dose chemotherapy with transplant and 110 who received standard chemotherapy. At two years after treatment, there were 55 deaths in both groups; seven deaths in the high-dose group were related to treatment.
In an Italian trial, the findings were similar. Among 382 patients randomized to receive either standard or high-dose therapy, there was little difference in survival rates. After five years, 77 percent of the patients who received standard therapy were still alive compared to 76 percent of those who received high-dose therapy.
Several transplant trials are still in progress, including a Dutch trial, reported at last year's ASCO meeting, which had some early results showing somewhat better results in the transplant arm.
However, it is clear that high-dose regimens have not yet been shown to benefit patients at any stage of breast cancer, said James N. Ingle, M.D., of the Mayo Clinic in Rochester, Minn., who discussed the data from the three trials. High-dose chemotherapy with transplantation "should only be used in the setting of a scientifically meritorious clinical trial," he concluded.
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