Transplant


Disclaimer: I'm not a doctor so don't take my info and try one at home. And if that doesn't disuade you, keep in mind that transplant is considered THE most extreme form of cancer treatment available.

If you want official information check this link out about Umbilical Cord Blood Transplants.

UCBT:
The procedure for an umbilical cord blood transplant (UCBT) is identical to a traditional bone marrow transplant, as is the intent. This type of transplant (taking something from one person and implanting it into another) is essentially an extreme form of immunotherapy. Immunotherapy is touted as being the future of cancer treatment, where you jump-start your immune system to attack the cancer. So far new immunotherapy treatment has been disappointingly slow in coming to fruition. Gene ID and development of cancer-specific drugs are more likely the future. But to do real attainable immunotherapy today means transplant; replacing your immune system with someone else’s.

Cord Blood: When a child is born you now have the opportunity to save the cord blood, for a fee. Within 10 minutes of birth the blood within the cord and placentia is removed and sent for processing. The stem cells are separated out, analized, and mixed with a preservative (DMSO) that helps keep the cells alive while frozen. This mixture ends up in a clear bag about the size of a saltine cracker. It is then stored in a freezer cooled with liquid nitrogen. The freezers as Duke are cylinders about 5 feet across and 4 feet high and each contain 3000 cords. There are 9000 cords in a space no bigger than a small bedroom. Each cord is stored at a specific address within the freezer and can be retrieved using a computer and robotic arm.

The cords are HLA typed and that is used to match the HLA blood typing of a patient. And here is a huge difference between bone marrow and cord blood: A UCBT can be done with only a 3 out of 6 match or above. In a standard BMT, anything less than a 6 out of 6 molecular match is very undesirable. 2/3 of the UCBTs at Duke are with 4/6 cords. So it can be easier to get a match. Another benefit to cord blood is that there is much less risk of severe GVHD (Graft vs. Host Disease); when the new immune system starts attacking things it shouldn’t, like organs and stuff. Also, the stem cells are very young and clean, unlike using an older person’s marrow. A big negative to cord blood is the quantity of material available – very little. This limits UCBTs to patients about 100 lbs or less (kids). Another factor as important as the typing is the cell dose (quantity of cells present). Also, engraftment time (when the new marrow starts to produce new cells) is longer. This exposes the patient to higher risk of infection. Average time to engraftment for bone marrow is 15 to 20 days, but typically 7 days longer for cord blood. This means longer hospitalization.

Leading up to transplant the patient’s old marrow is killed off completely using chemotherapy and/or radiation. Oh, and the bone marrow (yellowy spongy stuff inside bones) is where all new blood cells are produced. The transplant itself is very anticlimactic. The cord blood is infused by IV into the bloodstream over about 15 to 30 minutes, and you’re done. The stem cells find their way to the bone marrow producing regions in a matter of a few minutes. Then you wait for the stem cells to engraft and start producing new cells. First come the white cells, then the red cells, and last the platelets. This whole process can take many months. This is why bone marrow patients have to be isolated from crowded or indoor areas for long periods of time following transplant. The entire immune system can be abnormal for quite some time, not unlike HIV patients. One large danger during transplant is “failure to engraft”. This can lead to a second transplant, or more likely, that the patient’s own marrow returns. This is very unlikely in patients who have already received prolonged chemotherapy (like Spencer), because the original marrow is weakend and unlikely to come back faster than the donor’s.

About the first 30 days are the most critical, up until and a bit after engraftment when there is zero immunity. Many many things are watched and many many different drugs or antibiotics could potentially be used during this time to control or prevent complications. The first 100 days post transplant are watched very very carefully as well. Drugs are taken to control the amount of GVHD that is present (some GVHD is good, but too much is bad. Some GVHD indicates that the new immune system is working and fighting alien cells. This may also suggest the presence of GVL – graft vs. leukemia, which is what you want in the first place – the new immune system to attack leukemia cells). Many complications can continue well past 100 days, but if there is no severe GVHD then most stuff will eventually “burn itself out”. Each patient responds differently so it is impossible to predict when medications can be stopped or isolation reduced. Some people sail through it and some have a very tough time.

Patients who recover from transplant the quickest and have fewer GVHD issues have 6/6 matched sibling cords, somewhat of a rarity. However, and this is a huge "however", and please read it carefully and bring it up with your doctor if you are in the market for a tranplant, relapse rates are significantly higher with sibling transplants. This is because the new immune system is very closely related to the old immune system and therefore may not be as effective against the leukemia. So while you may see families jump up and down with happiness when they find out that a sibling is a "perfect match", it may come with a price. And that has to be weighed heavily in any decision. We have heard that relapse rates can be as high as 80% with an ultra rare identical twin cord blood transplant. And as transplant is often regarded as a one-shot deal, a mis-matched cord can be the best way to go.

The first successful UCBT was done in 1993 and of January 2003, about 3500 have been done worldwide – 3000 with unrelated cords and 500 with matched sibling cords. The total is easily over 4000 now. Duke does upwards of 100 per year now. Of the 3500 patients, roughly 50% are long-term survivors. Of course techniques have improved over the years and thus so have the success rates. Also, transplants are used for many different diseases, each with differing issues and outcomes so statistics like these are of limited use.