Metastatic Breast Cancer: An Evaluation of the Safety and Effectiveness of High Dose Chemotherapy with Autologous Stem Cell Transplant

Breast cancer is the leading cause of death for American women. Metastatic breast cancer, the focus of this paper, is defined as cancer that originated in the breast and has moved to lymph nodes and other bodily tissues. The treatment researched here is high-dose chemotherapy (HDC) followed by an autologous stem cell transplantation (ASCT). The safety and efficacy of HDC/ASCT are still under examination. Some arguments state that the effectiveness of HDC/ASCT may vary according to these non-treatment related factors: age, stage of disease at diagnosis, hormone receptor status, use of prior adjuvant chemotherapy, initial disease-free interval, response to prior chemotherapy, and number and sites of metastases. At this time it is still unclear if HDC/ASCT is a more effective treatment than traditional chemotherapy, as the survival rate is not significantly higher, while toxicity is higher. The health and safety of the women is important, and a safe treatment is one that does not kill the patient and does not result in permanent side effects. It has been concluded that higher levels of chemotherapy induce higher levels of toxicity and mental disturbances not limited to the following: nausea, myelosuppression, infection, mucositis and diarrhea, depression, stress, and fatigue. There is a low mortality rate associated with the actual transplant itself. The practice of re-infusion of stem cells has become a valuable method of hematopoietic rescue, as longer survival and few long term illnesses are associated with it. In the future more research should go into identifying the specifics that will define the women who will benefit from HDC/ASCT. The development of drugs that would not harm non-cancerous cells would be the ideal solution to cancer. Breast cancer is the leading cause of death for American women. In 2002, over 203,000 American women suffered from the disease and nearly 40,000 died (Williams, 2002). Surgical treatment to directly remove cancerous tissue involves either a lumpectomy or mastectomy where regional lymph node tissue is often removed to assess for cancer spread. Conventional treatments used in addition to surgery can include radiation therapy, hormone treatment, and standard-dose chemotherapy (Dervan, 2001). In some unfortunate cases, the cancer spreads beyond the regional lymph nodes and then disperses to other parts of the body; this is known as metastatic breast cancer (MBC) (Prucha and Bellenir, 2001). The focus of this paper is on the treatment of MBC, the most harmful and least curable form of breast cancer. High dose chemotherapy and autologous stem cell transplantation is another method of treatment that has recently become available to women with more advanced forms of MBC. Since stem cells are undifferentiated, they are a useful form of rescue in that they naturally replace depleted cells in the body. The use of stem cells as a rescue treatment for cancer and immuno-recovery was first practiced in the treatment of leukemia. After many years of trials on animals as well as humans, and confidence levels in the procedure were heightened, stem cell rescue was thought to be an ideal method for rebuilding the immune system. Stem cell transplants have since been used in addition to HDC to compensate for the severe damage that the immune system incurs in the process (Thomas et al., 1999). Often, the first step in this treatment program is a low dose chemotherapy treatment tailored to eliminate the cancer and induce remission (induction chemotherapy). Stem cells are then collected from the patient’s own bone marrow and are frozen for later use. HDC/ASCT differs from traditional chemotherapy (TC) in that stem cells