High dose chemotherapy and stem cell transplants were extensively used in the past to treat advanced breast cancer. Over the past 20 years, more than 15,000 women with advancer breast cancer have been treated using this unproven modality of treatment. This idea stems from the unproven theory "more is better" in terms of chemotherapy.
High dose chemotherapy followed by stem cell transplant exposes the patient to very high risks of side effects from the chemotherapy. This treatment uses very high doses of chemotherapy in an attempt to kill all the cancer cells. The bone marrow is not able to tolerate such high doses of chemotherapy, hence bone marrow stem cells from the patient is collected prior to chemotherapy to give back to the patient once high dose chemotherapy is completed. This taking of bone marrow stem cells and giving it back to the patient is called autologous bone marrow transplant.
In the early 1990s, after a few studies showing encouraging preliminary results, breast cancer patients and advocates began demanding the treatment. Even some state legislatures responded by mandating that insurance companies pay for the intensive procedure, which can cost up to $100,000 per case, much more than conventional treatments.
Vast majority of patients who were treated with high dose chemotherapy and stem cell transplant received the treatment outside the setting of any clinical trials. This resulted in continuation of this experimental modality of treatment without proper evaluation.
In the late 1990s, many randomized clinical trials were initiated to evaluate this treatment modality. The results of three of these trials were available by early 2000. The results from two such clinical trials showed that high doses of chemotherapy were no more effective than standard chemotherapy for women with advanced or high-risk breast cancer. Results from the third study contradicted these findings and came out in favor of the high-dose treatment. However, this study was later discounted after the lead South African researcher admitted fraud and misconduct.
As the results of these clinical trials became available the high dose chemotherapy followed by stem cell transplant started falling out of favor among oncologists in the United States. At that point, the American Society of Clinical Oncology (ASCO) recommended that women receive the treatment only if they were taking part in a "high-quality" clinical trial. Leading medical journals like the New England Journal of Medicine and Lancet expressed agreement with the ASCO recommendations. At this time high dose chemotherapy followed by stem cell transplant remains as an experimental approach, which needs further evaluation, using randomized clinical trials. Studies are ongoing in this field, but it unlikely to show any substantial benefit that would justify the side effects of high dose chemotherapy and bone marrow transplant.