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High dose chemotherapy, often combined with a bone marrow
transplant, is an experimental treatment used on some patients with advanced forms of breast cancer. However, new research
presented at the annual meeting of the European Society for Medical Oncology Congress
found that women who were given high dose chemotherapy did not live longer than patients
who received the standard dose of chemotherapy. The research did find that Herceptin, a drug that targets a certain genetic component in
breast cancer cells, was helpful for treating the disease.
The effectiveness of high dose chemotherapy is a source of debate among experts. Since
large amounts of anti-cancer drugs are administered with high dose chemotherapy, there is
the possibility that more cancer cells could be destroyed. However, high dose chemotherapy
may also increase the side effects of the treatment, which are already substantial for
some patients. Because prolonged high doses of chemotherapy may damage bone marrow cells,
which in turn can result is dangerously low blood cell counts, physicians may need to
perform bone marrow transplants (or stem cell rescues) on patients who are given high dose
chemotherapy. This procedure involves extracting cells from the patient’s bone marrow
prior to high dose chemotherapy and then re-injecting the cells after treatment.
In January 2000, a breast cancer researcher from South Africa admitted to falsifying
the results of a study that showed high-dose chemotherapy followed by bone marrow
transplants benefits patients with advanced breast cancer. A team of American scientists
became suspicious about the results of Dr. Werner Bezwoda's study after four similar
studies showed no benefit. However, other studies have shown high-dose chemotherapy to be
a promising treatment for some patients with advanced breast cancer.
The research presented at the European Society for Medical Oncology (ESMO) Congress
meeting involved 600 women with severe breast cancer. Dr. John Crown of St. Vincent’s
University Hospital, Dublin, Ireland and his colleague Professor Robert Leonard randomly
assigned each of the women to receive a certain course of breast cancer treatment. Some of
the patients received high dose chemotherapy. The women were then followed for an average
of five years.
At the end of the follow-up period, the researchers found that the women who received
high dose chemotherapy had no better chance of surviving breast cancer than the women who
did not receive the experimental treatment, although a longer follow up period may
eventually prove otherwise. "In truth, the results of conventional-dose chemotherapy
were better than expected," said Dr. Crown, in an ESMO statement. "However, we
must keep an open mind for the rest of the data, although our results already indicate
that any benefits that emerge from high-dose chemotherapy will be, at best, modest."
The researchers did find that treating women whose cancer cells expressed a certain
genetic mutation called HER2 overexpression responded
well to treatment with Herceptin (generic name, trastuzumab) which targets this mutation.
Laboratory testing can determine whether women carry the HER2 gene mutation. Herceptin is
widely available to women who overexpress the HER2 gene in the United States.
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