More Bad News for High-Dose Chemo
An independent audit has further rebuked the research protocol used in a controversial South African clinical trial that was evaluating the effectiveness of high-dose chemotherapy for treating breast cancer.
High-dose chemotherapy involves taking some bone marrow from a patient and treating it to remove any cancerous cells. (The bone marrow is where many new cells are produced.) The patient is then given extremely high doses of chemotherapy in an attempt to kill cancer cells throughout her body. Once she recovers sufficiently, the treated bone marrow is given back to her, and new (hopefully cancer-free) blood cells are produced.
The procedure involves considerable risk and, unfortunately, does not appear to be any more successful than standard chemotherapy regimens.
In recent years, the evidence against using high-dose chemotherapy to treat breast cancer has continued to mount. However, one notable exception was a major South African clinical trial led by Werner Bezwoda, Ph.D. of the University of Witwatersrand Medical School in Johannesburg. That trial was the first completed randomized trial comparing high-dose chemotherapy to less intensive chemotherapy regimens. Bezwoda's team concluded that high-dose chemotherapy was actually more effective, but the results were soon called into question.
Last year, the university announced that Bezwoda was under investigation for misrepresenting data from another randomized trial that he presented at the 1999 annual meeting of the American Society for Clinical Oncology. Shortly thereafter, independent researchers began uncovering significant discrepancies in Bezwoda's high-dose chemotherapy breast cancer trial as well.
Now, the Journal of Clinical Oncology has published an audit by an independent team of researchers led by Dr. Raymond Weiss of Georgetown University Medical Center in Washington, D.C.
Weiss' team concluded that the Bezwoda study "was not conducted in a scientifically acceptable manner." The investigators were unable to locate the records for at least a third of the patients enrolled in the trial, and the records of another third were of insufficient quality to verify the accuracy of the data.
Furthermore, the audit team noted, "The protocol was apparently written 9 years after the study was started, and only after another study by the same investigator (Bezwoda) was to be audited."
In the past year, other researchers have attempted to provided "corrected" results from Bezwoda's high-dose chemotherapy trial, and even those preliminary conclusions indicate that there is no significant benefit to using high dose chemotherapy for treating breast cancer.
A study published earlier in the Journal of the National Cancer Institute reached a similar conclusion. "Until a benefit is definitely demonstrated by randomized trials, we suggest that high-dose chemotherapy for primary breast cancer be restricted to clinical trials," wrote Dr. Gabriel Hortobagyi and colleagues from the University of Texas, M.D. Anderson Cancer Center in Houston. "At this point, there is insufficient evidence of benefit to justify its routine use in clinical practice."
SOURCES:
Journal of Clinical Oncology, June 1, 2001; 19:2771-2777
Journal of the National Cancer Institute, February 2, 2000; 92(3):225-233
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