No Survival Benefit with High Dose Chemotherapy (dateline February 27, 2003)
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 patients 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. Vincents 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.