Step 4 ¡R eview with the physician the pros and cons of HDT with stem cell rescue (and/or stem cell harvesting without immediate transplant). ¡ S tem cell harvesting can be planned if the patient and the physician concur that this is the best approach. If there is no plan for harvest and/or HDT, a plan for ongoing maintenance (“continuous therapy”) or follow-up treatment is required. ¡ I f the response to induction therapy is deemed inadequate, then other therapy may be required before proceeding to transplant. “Questions and answers” about HDT, as well as “Questions to ask the doctor” about the potential procedure, are listed later in this booklet.
How stem cells are collected Blood stem cells are located in the bone marrow. Until about 20 years ago, the only way to collect these stem cells was to have the patient or donor receive a general anesthetic and undergo as many as 50 to 100 bone marrow aspirations from the back of the pelvic bone to remove enough bone marrow and stem cells to use for future transplant. This was obviously painful, invasive, and inconvenient. The discovery that stem cells could be collected from the bloodstream by giving a patient or donor injections of stem cell growth factors (colony-stimulating factors or CSFs) such as filgrastim, pegfilgrastim, or sargramostim to trigger the release of bone marrow stem cells into the bloodstream was a major breakthrough.With refinements over the years, this has become the standard method. It is rarely necessary to use the old method of direct bone marrow harvesting from the pelvic bone.
Protocols for collecting stem cells from the blood stream There are three main protocols for collecting stem cells from the blood stream (peripheral blood stem cells or PBSC): ¡G iving standard growth factors alone. ¡G iving growth factors with chemotherapy. ¡G iving growth factors with an additional mobilizing agent.
1. Giving growth factors alone Growth factors stimulate the blood stem cells in the bone marrow to multiply and to be released into the blood stream. These medications are administered subcutaneously (under the skin). This procedure is commonly known as a “shot.” The white cell growth factors are the ones used in high doses for stem cell harvest or “mobilization.” The injections are given daily for three or more days. Stem cells are usually collected on the 12
818.487.7455 • 800.452.CURE
