Researchers are currently studying reduced-intensity stem cell transplantation in clinical trials. This type of transplant — sometimes called nonmyeloablative transplant — is a modified version of allogeneic transplantation. The chemotherapy or radiation dose is reduced, yet still high enough to suppress the immune system and enable graft versus tumour (GVT) effect in which the patient's new immune system (originating from the donated stem cells) may destroy the bulk of remaining cancer cells.

Reduced-intensity stem cell transplantation can be a good option for some patients who may not be able tolerate allogeneic stem cell transplant with higher-intensity chemotherapy. They include:

• Older patients
• Patients who have other medical conditions
• Patients who have certain infections
• Patients with less rapidly progressive blood cancers

Reduced-intensity allogeneic stem cell transplants are usually performed with peripheral blood stem cell grafts, although stem cells from marrow or cord blood can be used. In some instances in which the donor's immune system doesn't completely replace that of the recipient (a state called mixed chimerism), extra boosts of donor immune cells (lymphocytes) can be infused to improve the engraftment and possibly the immune system's antitumour effects. These infusions are called donor leukocyte infusion therapy.

Because reduced-intensity transplantation is relatively new, its risks and benefits haven't yet been clearly defined. One definite advantage, though, is that patients in their 70s and 80s can now be considered for stem cell transplantation.

How to Find a Transplant Center

Your doctor can help you find a transplant center that's studying this type of procedure in clinical trials. For more information about finding a center, see Choosing a Cancer Specialist or a Treatment Center. You can also contact a Leukemia & Lymphoma Society (LLS) Information Specialist at (800) 955-4572 for help or information.