Dr. George Santos on Bone Marrow Transplantation for Cancer Today. Originally published in 1989.
Bone marrow transplants for malignancy are performed as highly intensive treatments to eliminate every possible malignant cell, particularly in leukemia and lymphoma. With this approach, we rescue patients from the toxicity to the bone marrow induced by cancer treatment. For example, in patients with acute lymphocytic leukemia who are in second remission, we can expect a 50% to 60% disease-free survival, with patients surviving from 15 to 16 years after the transplant. In patients with acute myelogenous leukemia who are in first remission, our data suggest a disease-free survival of close to 65% of patients thus treated. With chemo-therapy in first remission, however, results vary, with long-term survival ranging from 20% to 40%. Most physicians obtain only about a 20% long-term survival with chemotherapy alone.
In subsequent remissions in patients with acute myelogenous leukemia, the results with transplantation, while still encouraging, are not quite as good. In patients with chronic myelogenous leukemia, if the transplant is done during the chronic phase of the disease, one may expect from 50% to 65% disease-free survival, with patients in some series surviving 10 or 15 years. More recently, patients with non-Hodgkin’s lymphoma or Hodgkin’s disease, who are not curable by conventional methods, have had disease-free survival of from 50% to 60% with bone marrow transplants.
We have been using family members for donors of bone marrow; unfortunately, however, donors are not available for most patients. We are now trying another approach, that of using the patient’s own bone marrow, first purging it of any tumor cells. With this approach in acute myelogenous leukemia, we have done relatively well in patients in second and third remissions, achieving a 30% disease-free survival in over 60 patients.
The most exciting application of this approach has been in the treatment of the lymphomas. We have treated from 30 to 40 lymphoma patients (about 1,000 patients worldwide have been treated by this method), with the results suggesting that from 50% to 60% of patients will have long term, disease-free survival, with a good number being cured.
As to the extension of bone marrow transplantation to the treatment of other types of malignancies, early results in multiple myeloma are encouraging. This is also true with myelodysplastic syndrome, a condition often leading to leukemia. Other tumors likely to be responsive to this treatment are breast carcinomas that are metastatic and not responsive to other forms of therapy. Early work indicates that ovarian carcinoma seems to be a likely candidate for this approach, with first results highly encouraging. Small cell carcinoma of the lung is also responsive to this approach. Some investigators have used autologous transplantation in patients with small cell carcinoma of the lung and have been encouraged by their early findings. Also, there have been some studies of testicular tumors, not curable with other therapies, that have shown good results with bone marrow transplants. Along with these exciting applications of this treatment, it has been found that in pediatric neuroblastomas, autologous bone marrow transplants done early have given good results.
With the good results obtained in treating the leukemias with bone marrow transplants, and the availability of platelets and superior antibiotics, we can expect a useful extension of bone marrow transplantation for more intensive treatment of common malignancies.
