Conditioning Regimen and the Transplantation of Unrelated Donor Umbilical Cord Blood in Patients With Hematologic Malignancies.

The traditional way of doing a donor transplant is to give high doses of chemotherapy and radiation before giving the stem cells. However, high doses of chemotherapy and radiation can have serious side-effects. The doctors think that the transplant will be safer and more likely to be successful with reduced doses of chemotherapy and radiation. The purpose of this study is to find out how good a combination of chemotherapy and radiation at reduced doses followed by a cord blood transplant are at treating cancer. The stem cells chosen for the transplant are from umbilical cord blood. Umbilical cord blood is collected from healthy newborn babies and frozen. One cord blood collection is called a "cord blood unit." On transplant day, the cord blood will be given through the catheter just like a blood transfusion. Transplants done this way have been successful. However, this type of transplant is fairly new. Therefore, it is important to study it so the doctors can better understand how it works. Most blood or bone marrow transplants using donor stem cells are done as part of a study. When patients are on a study we test new ways of treating them which we think may be better than the old ways. We collect information about the result of this treatment so we can understand how well the treatment works. This is so we can learn better ways to treat our patients.