What is autologous hematopoietic stem cell transplantation?
In this treatment approach, we give a dose of chemotherapy that's three to ten times stronger than the usual amount. This is done to maximize the effect against cancer. After that, we use the patient's own hematopoietic stem cells, which we previously collected and froze for safekeeping (usually from their bloodstream), to help their bone marrow recover. The high-dose chemotherapy can cause damage to the bone marrow, so this step is necessary.
In cases of neuroblastoma, when is autologous stem cell transplantation performed?
In treating high-risk neuroblastoma, we first use combination chemotherapy to induce remission, then follow up with surgery to remove any remaining tumor. After this, we administer a high-dose chemotherapy to maximize the anticancer effect. This high dose can suppress the bone marrow, so to offset this, we thaw and infuse hematopoietic stem cells that we previously collected from the bone marrow. This method, known as autologous stem cell transplantation, is especially used for high-risk patients. We typically perform this transplantation process in two consecutive sessions.
What is the process for collecting autologous hematopoietic stem cells?
Autologous hematopoietic stem cells are only found in small amounts in the peripheral blood. To collect enough cells for transplantation, we need to move more cells from the bone marrow into the bloodstream. We do this using chemotherapy drugs or hematopoietic growth factors.
Most patients have their stem cells collected after they've had chemotherapy treatment, such as salvage therapy. This is done once it's confirmed that there are no cancer cells left in the bone marrow and once their white blood cell counts start to recover.
The collection process happens in a specialized unit called an apheresis unit and usually takes about 4-5 hours per session. Depending on how many stem cells we can collect, the process can take as little as one day or as long as two to three days.
Once we've collected enough stem cells for the transplant, we freeze them until the day of the transplant.
What are the preparatory steps before autologous stem cell transplantation?
Transplantation involves giving high-dose chemotherapy or radiation, various medications and fluids, and many blood transfusions. These procedures can cause significant complications related to the transplant. To have a successful transplant, a patient needs to be strong enough to withstand the process.
That's why pre-transplant evaluations are so important. They help us understand the patient's disease status and overall health and make sure they are physically able to handle the transplant. This includes visits with dental and ear, nose, and throat (ENT) specialists to find and treat any possible infections before the transplant.
We also use diagnostic tests like pulmonary function tests and echocardiograms to check how well essential organs are working. Plus, we do blood and urine tests for infections to evaluate the patient's condition before going forward with the hematopoietic stem cell transplant.
