Myelodysplastic syndromes (MDS, or myelodysplasia) are a group of diseases which all affect, to a greater or lesser extent, the production of normal blood cells in the bone marrow. MDS occurs as a result of a mutation in one or more of the genes that control blood cell development. These changes result in abnormal growth of blood stem cells.
The abnormal mutation is preserved when the affected stem cell divides and produces a “clone” with the same defect. This is why MDS is sometimes described as a “clonal blood stem cell disorder”. Mutations in dividing cells occur all the time and cells have clever ways of stopping these abnormalities persisting and causing problems within the body. The longer we live, however, the more chance we have of acquiring mutations that manage to escape these safe-guards. That is why MDS, like most leukemias and other cancers, becomes more common as we get older.
In MDS, abnormal bone marrow stem cells (called blast cells) produce increased numbers of immature blood cells. These cells do not grow properly and often die prematurely. This results in lower numbers of mature red blood cells, white blood cells and platelets being produced. The blood cells that do survive are often of poor quality, are abnormal in shape (dysplastic) and are unable to function properly. This means that people with MDS often have a very active bone marrow but a low number of circulating blood cells.
How bad is my MDS?
There are different types of MDS and the disease can vary in its severity and the degree to which normal blood cell production is affected. Over 90% of people with MDS are over the age of 60. People with a mild case are often found to simply be a bit anaemic and have a low percentage of blast cells in their marrow (under 5%). Sadly, this is not my case. When I was originally diagnosed in late December, 13% of my bone marrow was made up of the blast cells, and the anemia I had because of it was very severe. I wouldn’t have lasted long before dying (a few weeks maybe…). This put me in a high risk MDS category.
Thankfully, diagnosing MDS with a bone marrow biopsy is a straight forward venture and there is no grey area as to whether MDS is actually what I have. In the same way, there is no grey area as to my treatment. Getting a whole new immune system is the only way forward. This means, I need a bone marrow transplant. If I didn’t get a bone marrow transplant and could just keep borrowing blood from the generous donors who’ve kept me going the last couple months, the blast cells would take over my marrow and eventually end up in my blood stream and that would be the end for me (in a matter of a few months).
- Find a donor: My middle sister is the closest match! Sadly, we are not a full match, which decreases chances of a successful transplant… but new data is showing that a half match sibling can be as good as a full match stranger. I am thrilled at the chance to be all the more bonded to my dear sister through this process.
- Get blast cells DOWN: Unfortunately, one can’t just go in for a transplant with 13% blasts and expect good results. The chance of them sticking around and reproducing after the transplant is too high. I first underwent a month long cycle of a kind of chemotherapy called decitabine. Sadly this left my blast cells at 12%. Now we’re on to a heavier weight chemotherapy called vyxeos with the same purpose of getting the blasts low enough.
- Transplant: Blast cells down? We move on to full body radiation and myeloablative chemotherapy as an inpatient a few days before transplant day to ensure as much as possible that the new marrow engrafts. This comes with a load of tests right beforehand as well to make sure my body can handle the chemo.
- Post Transplant: More chemotherapy of a different flavor to subdue my sister’s fully developed cells, and keep them from full on attacking me (a small attack from her cells can actually be beneficial in finishing off the blast cells.)
- Isolation: I’ll be in the hospital in a special room while my immune system rebuilds from the ground up. This can take about a month. I can still see people but have to take great care to not get sick.
- I go home! Sadly, that’s not the end. My chances of survival are not an easy statistic to nail down since most people with high risk MDS are not in their 30s. What is clear is that the longer I stay alive post transplant, my chances of staying in remission improve. There is also the risk of chronic graft versus host disease… we’ll see when we get there.