Delayed complications and long-term effects after bone marrow transplantation.

Bone marrow transplantation is being used with increasing frequency and success for an expanding number of indications. At present, more than 1000 patients are surviving more than 5 years and several hundred more than 10 years after transplantation. Extended observation periods have shown that numerous complications have to be expected in these patients, particularly in those given TBI as part of the conditioning regimen. However, other factors including chemotherapy, GVHD, viral infections, host environment, and genetic factors also contribute to the problem. It has been pointed out by critics of bone marrow transplantation that success is often reported as disease-free survival, meaning survival in remission. However, there are, obviously, secondary problems that can significantly impair patients' quality of life, even though their leukemia (or lymphoma) is in unmaintained remission. Very few data on quality of life in long-term surviving patients have been reported. Several studies are currently ongoing (Forman S, Blume K, personal communication), and the results are urgently needed. It will also be of interest to compare patients given, allogeneic transplants with those given autologous marrow infusions in an attempt to determine to what extent conditioning regimens and alloreactivity contribute to long-term side effects. It will be even more important to design regimens that are less likely to induce these problems and to design therapeutic approaches to treat complications effectively.