High-dose chemotherapy followed by a bone marrow transplant remains a controversial experimental treatment for breast cancer. While some researchers believe this treatment may be the only viable option for women with advanced (metastatic) breast cancer, others do not see any clear benefit to the therapy. High-dose chemotherapy received negative attention in early 2000 when a South African researcher admitted to falsifying results of a study that showed high dose chemotherapy followed by bone marrow transplants benefits advanced breast cancer patients. Now, several recent studies have also failed to find any increase in survival time for breast cancer patients who undergo high-dose chemotherapy.
High-dose chemotherapy involves treating patients with increased dosages of anti-cancer drugs. Because prolonged high doses of chemotherapy drugs can damage bone marrow cells and contribute to dangerously low blood cell counts, physicians may need to perform bone marrow transplants (or stem cell rescues) on patients who receive high-dose chemotherapy. A bone marrow transplant involves injecting previously preserved bone marrow cells into the body in order to produce more blood cells.
The latest studies on high dose chemotherapy/bone marrow transplants were presented at the May 2001 meeting of the American Society of Clinical Oncology (ASCO) in San Francisco, California. The CALGB trial was one of five major high-dose chemotherapy clinical trials sponsored by the National Cancer Institute. The trial enrolled 783 patients with Stage II or Stage III breast cancer who were found to have more than 10 cancerous axillary (underarm) lymph nodes. The other two studies reported at the ASCO meeting were early results of a Canadian trial of advanced breast cancer patients and an Italian trial of 382 breast cancer patients.
The results of all three trials revealed no increase in survival for the breast cancer patients who underwent high-dose chemotherapy followed by bone marrow transplants. In the CALGB trial, lead researcher William Peters, MD of the Barbara Ann Karmanos Cancer Institute in Detroit, Michigan, and his colleagues had followed approximately one half of the 783 patients for over five years. The researchers found that the likelihood that breast cancer patients would relapse was the same regardless of whether the patient received high-dose chemotherapy or intermediate-dose chemotherapy. (Intermediate-dose chemotherapy involves receiving a high drug dosage than standard chemotherapy. Patients in the study who received intermediate dose chemotherapy were also given additional treatment to help regain normal blood cell counts).
Dr. Peters and his colleagues also found that 32 patients in the CALGB study died as a result of high-dose chemotherapy. None of the patients who received intermediate-dose chemotherapy died from the treatment. However, some of the younger women in the study (under age 45) who had fewer cancerous lymph nodes appeared to have somewhat better responses in the high-dose chemotherapy group. Therefore, Dr. Peters says high-dose chemotherapy followed by bone marrow transplants may still be a "viable treatment option" in younger women who receive the therapy in closely monitored clinical trials.
The other two trials reported at the ASCO conference produced similar results. In the Canadian study, 110 advanced breast cancer patients were treated with high-dose chemotherapy and another 110 patients were given standard-dose chemotherapy. After two years, the number of deaths in the two groups was identical (55 deaths; seven deaths in the high-dose chemotherapy group were related to treatment). In the Italian study of 382 breast cancer patients, survival rates were the same regardless of whether the patients were treated with high-dose chemotherapy or standard-dose chemotherapy.
The reporting of these latest studies on high-dose chemotherapy comes on the heels of an editorial decision to retract a study on high-dose chemotherapy that appear in the Journal of Clinical Oncology. The decision was made after an investigation revealed that South African researcher Dr. Werner Bezwoda falsified much of the data from his 1995 study that showed that high-dose chemotherapy significantly benefited breast cancer patients. In fact, many of the participants had not received the treatment described in Dr. Bezwoda’s published study. Dr. Bezwoda also admitted to falsifying results of a similar study in 1999.
Despite the negative publicity for high-dose chemotherapy/bone marrow transplants, some researchers believe that the treatment may be beneficial to select patients. A Dutch study and several additional trials are currently underway that may provide more positive results. Currently, the treatment is considered experimental for breast cancer patients and should only be performed in closely monitored clinical trials after other treatment options have been explored. Bone marrow transplants are more commonly used to treat some forms of leukemia (cancer of the blood) and lymphoma (cancer of the lymphatic tissue).
- The May 12, 2001 National Cancer Institute report, "Breast Cancer Transplant Trials Continue to Show No Benefit," is available at http://cancertrials.nci.nih.gov/news/meetings/asco01/bmt051201.html
- The February 9, 2000 Imaginis report, "Breast Cancer Study Results on High-Dose Chemotherapy Falsified," is available at
- http://www.imaginis.com/breasthealth/news/news2.09.00.asp
- For more information on studies presented at the 2001 meeting of the American Society of Clinical Oncology, please visit http://www.asco.org/
- To learn more about chemotherapy, including high-dose chemotherapy, please visit http://www.imaginis.com/breasthealth/chemo.asp
