Perspectives on stem cell transplants have changed since the first successful procedure in the 1950s. They were once considered treatments of last resort for young cancer patients who were otherwise healthy and had an identical twin bone-marrow donor. As technology, stem cell sources and knowledge of the immune system changed, more patients have been able to benefit from the procedure.
"We have become much better at doing transplants and identifying patients who should have them," said Joseph Tuscano, associate professor of hematology and oncology and part of the UC Davis stem cell transplant team. "The process is much safer, much more controlled and much more tolerated now than it was even 10 years ago."
Today, transplants can be a preferred treatment for cancers such as leukemia, lymphoma and myeloma, as well as for congenital or acquired bone marrow disorders. They can be used to replace an abnormal immune system or help circumvent the damage caused by high-dose chemotherapy.
In addition to bone marrow, stem cell sources now include peripheral and umbilical cord blood. Nearly half of all transplants are allogeneic, in which cells are provided by a donor with closely matched human leukocyte antigens. An autologous transplant involves using the patient's own stem cells following treatments to "coax" them from bone marrow.
The process begins with intensive chemotherapy for up to one week to eliminate the patient's own immune system and, in the case of malignancy, eradicate diseased cells. In a matter of hours, the donor's – or patient's own – cells are transferred through intravenous infusion. From that point on, the patient's bloodstream is forever transformed.
When donor cells are used, physician oversight is required for months to years to monitor for graft-versus-host disease, which causes the new immune system to attack its host's organs. Autologous transplant patients are usually referred to the care of their own oncologists after just one or two months.
"A stem cell transplant is certainly not considered an easy treatment, and it's definitely not for every patient. But it can be very powerful and effective in fighting cancer," says Tuscano.
Carol Richman, director of the UC Davis Stem Cell Transplant Program, plans next to expand the use of umbilical cord cells for patients who do not have matched donors, use stem cells to treat more non-malignant diseases, and work with the new UC Davis Institute for Regenerative Cures to develop novel treatments for restoring failing organs and preventing graft-versus-host disease.
"Over the past 15 years, stem cell therapy has matured, enabling more patients to receive this lifesaving treatment," she says. "The environment for major progress in stem cell science is very supportive right now, and UC Davis will continue to play a lead role in this field of medicine."