Stem cell transplantation, otherwise known as bone marrow transplantation, is the infusion of healthy blood-forming stem cells into a patient to replace or supplement the bone marrow. Stem cell transplants can be used for patients whose stem cells are not healthy, either because of an inherited or acquired problem or as a result of damage by treatments for cancer, such as chemotherapy and/or radiation therapy.
While the prospect of a stem cell transplant may be frightening to a young person, it can in many cases provide hope of a cure. Doctors and clinicians experienced in the procedure can answer patients’ and parents’ questions and address their concerns. A variety of support services are available for patients and families before, during, and after the procedure.
Stem cell transplants have traditionally been used in children, teens, and young adults to treat blood-related cancers such as leukemia and lymphoma, as well as non-cancerous blood disorders such as aplastic anemia, sickle cell disease, and thalassemia. Increasingly, they’re also being used to treat metabolic diseases, immunodeficiencies, and other disorders.
The Transplant Process
Here’s what to expect during a pediatric stem cell transplant.
Pre-Transplant Workup
Before treatment, patients have a thorough physical exam, including evaluation of their heart, lungs, kidneys, teeth, ears, eyes, and other organs to ensure they can tolerate therapy.
Conditioning Therapy
Conditioning therapy refers to the high-dose chemotherapy and/or radiation that children receive before their stem cell infusion. The day a child receives the bone marrow or stem cells is called Day Zero (Day 0). The days prior to Day 0 are the days that a patient receives the conditioning therapy.
There are several goals of conditioning therapy: To kill cancer cells in patients with a malignant disorder and to kill normal immune cells in the marrow cavities of the bones so the new marrow will be accepted and have room to grow. If the child is receiving cells from another person, conditioning therapy has a third goal: To suppress the child’s immune system so it will not reject the donor’s cells.
Day 0: Stem Cell Infusion
Day 0 is the day the stem cells are infused through the child’s central venous line.
There are two types of stem cell transplants:
- Autologous transplants, in which the patient’s own stem cells are collected, stored in a special laboratory, and re-introduced into the patient’s system intravenously following chemotherapy.
- Allogeneic transplants, in which stem cells are collected from a tissue-matched donor (a matched sibling, an unrelated donor, a mismatched family donor or umbilical cord blood) and delivered intravenously.
Expected Side Effects
After Day 0, patients may begin to have some of the expected side effects of the conditioning therapy such as nausea, vomiting, diarrhea, and mouth sores.
Infections After Transplant
Stem cell transplantation patients are at high risk for infections because the immune system is suppressed from the conditioning therapy. Patients who receive stem cells from another person have an additional risk of infection since they take medications that suppress the new immune system. Patients need these immunosuppressive medicines to help prevent graft-versus-host disease.
Engraftment
After the marrow has been infused, the number of neutrophils, a type of white blood cell, slowly increases over the next two to four weeks. Engraftment occurs when the stem cell graft is making enough neutrophils to offer some protection against bacterial infections.
Graft-Versus-Host Disease
If your child receives stem cells from someone else, there is a risk of graft-versus-host disease (GVHD). It is caused when the donor’s (graft) T lymphocytes, a type of white blood cell, react against the cells of the patient (host). The effects of GVHD are most likely to involve the skin, gastrointestinal tract (digestive system), and liver. GVHD may occur before or after stem cell engraftment. In general, acute GVHD occurs before Day +100 and chronic GVHD occurs after Day +100.
Other Side Effects
The conditioning therapy and medications used during transplant may cause other side effects and toxicities. At Dana-Farber/Boston Children’s, these are discussed during the initial consent meeting. Blood tests, X-rays, CAT scans, MRI scans, ultrasounds, or biopsies (tissue samples) of certain tissues may help in the diagnosis of such problems.
Discharge
Patients are considered for discharge after engraftment has occurred. They must also be medically stable and able to take all required medications.
Restrictions after Discharge
Autologous transplant patients should not attend school or visit other public indoor places for two months after transplant. Allogeneic transplant patients should not attend school or visit indoor public places for nine to 12 months after transplant, depending on their health status.
Questions and Answers
Here, Leslie Lehmann, MD, clinical director of the Pediatric Stem Cell Transplant Center at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, answers questions from parents and other caregivers about transplants for young patients.
Is a stem cell transplant safe?
Survival rates for young patients undergoing a stem cell transplant, either autologous or allogeneic, are in general very high.
To determine if a patient is a good candidate for a stem cell transplant, doctors consider a variety of factors, including:
- The patient’s general health
- Results of medical tests
- The reason for the transplant and the control of the patient’s underlying disease
- Previous medical treatments
- The likelihood that the disease will respond to treatment or return after transplant
The Hematopoietic Cell Transplant Program at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center is one of the largest and most experienced pediatric stem cell transplant programs in the world, performing more than 100 transplants each year. The center includes highly trained, knowledgeable pediatric stem cell transplant physicians and scientists, as well as psychosocial health providers and resource specialists to help parents and families with the emotional, logistical, and financial aspects of transplant.
What kind of stem cell transplant will my child need?
The type of transplant a patient receives – autologous or allogeneic – depends on several factors, including the specific disease a patient has, the availability of a suitable donor, and the general health of the patient.
Will my child’s disease be cured by the transplant?
The likelihood of a cure depends on the disease being treated and its severity at the time of transplant. In leukemia, for example, the more the disease has been controlled at the time of transplant, the less likely it is to recur. For non-malignant blood diseases such as sickle-cell anemia, immunodeficiency disorders, and bone marrow failure, cure is very possible and varies with the type of disease and type of donor.
What are the late side effects of a transplant?
There can be late side effects, which can emerge months or years after the procedure and largely depend on the conditioning therapy used in preparation for the transplant. For patients receiving donor stem cells, this can include chronic graft-versus-host disease, a complication in which the new cells attack healthy tissue.
Many children are infertile post-transplant. For some, the loss of reproductive function is temporary; for others, it can be permanent. At Dana-Farber/Boston Children’s, specialists in the Pediatric Fertility Preservation Program discuss fertility preservation options with the family of every patient undergoing a transplant.
Conditioning therapy can sometimes impact a child’s physical growth but usually doesn’t affect neurocognitive development.
What is parents’ and caregivers’ role during and after the transplant process?
While young patients are in the hospital, doctors, nurses, and support staff are trained to handle their needs. When they go home, they’ll be prescribed a range of medications that parents may be expected to administer if they are comfortable doing so. If patients require intravenous fluids or nutrition at home, parents can administer them if they’ve undergone extensive training beforehand.
Because patients need to be isolated from others for several months following the transplant, an adult will need to be home with them while their immune system recovers. (In Massachusetts, schools are required by law to provide home-schooling services, either by an in-person tutor or online, to homebound children.) At Dana-Farber/Boston Children’s, every transplant patient is assigned to a psychosocial health provider to help with the adjustment to life after transplant. The center also has a resource team to help families with financial and insurance issues.
How should parents discuss the transplant with the child and siblings?
Psychosocial health providers from the Dana-Farber/Boston Children’s work closely with parents on age-appropriate ways of explaining the transplant process and its aftermath to children and young siblings.
What support services are available to parents of young transplant patients?
At Dana-Farber/Boston Children’s, psychosocial health providers offer counseling and support to parents and, if needed, connect parents to mental health services in the community. Chaplaincy services are also available.