Yesterday Huong drove me to Charm City for my first stem cell transplant consultation. This took place at the Kimmel Cancer Center at Johns Hopkins. Before I get into what transpired there, though, I will first provide a brief rundown on what stem cell transplant involves. I will do that in this post, and then discuss the details of the consultation in a subsequent post; otherwise, this one will go on way too long.
I will not repeat here the description of how multiple myeloma works included in an earlier post; I encourage the reader to review that material first, before continuing with this post.
What I have been getting for the past four months is low-dose chemotherapy. This has been killing the cancer cells, meanwhile having fairly minimal impact on the systems that must be kept working. In my case there was some concern about cardiac effects, but they turned out to be non-life-threatening. There are some other symptoms (e.g. muscle cramps and spasms), but they are being managed as well.
Stem cell transplant is a strange combination of early 21st century biochemical magic with a nearly medieval brutality. In its simplest possible terms, it is just one-time, very-high-dose chemotherapy; all of the other maneuvers involved are designed either to prepare the patient for this chemotherapy, or to help the patient survive the effects.
Before anything else, the patient must be vetted for eligibility by means of a series of tests designed to gauge the patient's ability to survive the process. High-dose chemotherapy, although it has become much better targeted over time, is still a relatively blunt instrument; it puts tremendous stress on certain internal organs and systems, and although permanent damage is relatively rare, temporary damage is much more common. These organs and systems must be tested to ensure that they will be able to take the strain without completely failing, and eventually recover their normal ability to function. These tests also provide a baseline picture of the patient's status that can be compared with that provided by the same tests performed later in the process.
Some types of stem cell transplant involve third-party bone marrow donors, but in the type I will get -- called an autologous stem cell transplant -- only the patient's own bone marrow is used. The transplant begins by injecting the patient with a drug that will cause stem cells to migrate from their usual residence in the bone marrow into the bloodstream. Once this has happened, the patient is connected to an "apheresis" machine, which extracts blood, filters out and retains the stem cells, and returns the remaining blood to the patient. The stem cells are frozen and stored for future use.
Once enough stem cells have been harvested, the patient is given the high-dose chemotherapy treatment. The objective is to kill all the cancer cells remaining in the patient's body after the last cycle of low-dose chemotherapy. But the drugs also kill the patient's remaining stem cells, thereby destroying the ability to manufacture blood cells; so once the dust has cleared, the patient is reinjected with the stem cells harvested earlier. These will make their way back to the bone marrow, take up residence there, and begin generating blood cells again. Eventually the patient ends up having a restored immune system, minus the cancer cells.
Patients who fail to survive this process almost never succumb while it is in progress; rather, they fail to respond well to post-procedure complications. The patient is extremely vulnerable to infection in the interval between being given the chemotherapy and the full recovery of the immune system. Besides the dangers posed by external vectors of infection, the body itself is normally host to colonies of various types of bacteria and fungi, which a healthy immune system will keep in check; but the crippled, post-chemotherapy immune system will not be able to perform this task for some time, during which these colonies can grow in an uncontrolled fashion, invading organs from which they are usually kept away. During this time, the patient must be constantly watched for the earliest signs of infection; when such appear, they must be accurately diagnosed (not always such an easy task) and treated, before they have a chance to get out of control. For this reason, the patient must live in close proximity to the cancer center for at least the first month from the beginning of treatment.
Nowadays the entire stem cell transplant procedure is done on an outpatient basis; the patient is never kept overnight, unless of course something goes badly wrong. Post-procedure, patients may have to be admitted to the hospital if they appear to be in danger due to infection, or to the side effects of the chemotherapy drugs.