No Reward Without Risk
A lot has happened since I last posted about my bone marrow being clean. The short version is that I'm scheduled for bone marrow transplant on February 28th.
The long version is that my transplant is coming with an additional layer of potential complications. But, first thing's first, let's catch you up.
I completed round three of SL401 in early February. After round three, the tumor in my right forearm was the smallest it's ever been. I was encouraged by that progress because we wanted the tumor to be as small as possible going into transplant. Unfortunately, in just the few weeks that have passed since my last SL401 dose, the tumor began to regrow.
Although this was discouraging, hope is certainly not lost. I recently spoke with a friend who had BPDCN and transplanted last year, and she told me the same thing happened to her after her third cycle of SL401. She is now six months post-transplant and cancer-free.
Nevertheless, my physician suggested that we spot treat my remaining skin tumors (there's a very tiny one on my stomach in addition to the one on my forearm) with radiation. I had my first treatment yesterday and will have the second this coming Monday. Thankfully, the radiation procedure was quick and painless.
In the background of the past weeks, my medical team has been working hard to arrange a transplant quickly since this cancer is so aggressive. Unfortunately, there are no perfect 10/10 matches available to me on the international donor registry. There are, however, several 9/10 matches. Because the risk of mortality in waiting for a perfect match is higher with this particular cancer than proceeding with a mismatched unrelated donor transplant, we are moving forward with one of the 9/10 donors.
After reviewing blood test results, my physician chose the donor with the mismatch that is least risky. My donor (whose identity is unknown to me and will remain so for around a year) and I have spent much of February undergoing additional testing to confirm his fitness to donate and my fitness to undergo transplant. I believe (although I'm not 100% sure) that testing for my donor consisted of additional blood tests and maybe a few other tests to confirm his ability to safely undergo surgery. My workup included EKGs, twenty or so vials of blood labs, a chest x-ray, an echocardiogram, pulmonary function tests, a dental appointment/x-rays to get dental clearance prior to transplant, a lumbar puncture to check that BPDCN hasn't spread to my brain (which it can do, but thankfully for me it's not there yet). I also had meetings with a physical therapist, social workers, the radiation oncology team, my transplant coordinator, a transplant education session, and my transplant physician.
Everything was moving along swimmingly until yesterday. My physician told me that unfortunately, I have a very high level of antibodies in my current immune system that makes my transplant more risky.
One issue with my antibodies is that I will reject 97% of the population's platelet donations. I will need platelet transfusions for several weeks following transplant until my donor's immune system takes over as my own. Until that time, my blood counts, including platelets, will be dangerously low. Most transplant patients need platelet transfusions once or twice every week. Because of my antibodies, my platelet levels will be more difficult to increase and maintain. I will likely require 3-4 platelet transfusions every week for 2-3 weeks after transplant. The transfusion team at the James is currently searching nationally for platelets that closely match my own so we have enough supply, but the chances of unrelated donors matching me sufficiently are 1 in 10,000.
Platelet donation also becomes a bit more complicated than simple blood donation because it has a shelf life of only about a week. Our backup plan is to use platelets from my parents, but they are both only half matches. We are holding their platelets in reserve for now until we exhaust our options with other potential platelet donors.
In addition to platelets, I have antibodies against the locus where my donor and I are mismatched. We still have the best available donor because I also have antibodies against the mismatches with the other 9/10 donors that pose even greater risk. Unfortunately, the antibodies don't simply go away after the intensive pre-transplant radiation and chemotherapy conditioning regimen that will all but destroy my existing bone marrow.
My physician explained to me yesterday that this ultimately poses two potential problems. The first is that my antibodies may cause engraftment failure--in other words, my body will attack the new immune system being donated to me as foreign and the transplant won't take. The antibody issue increases my risk from about 0% to 1.5% chance of engraftment failure. Although it seems small, that's a risk I didn't want to have going into this because engraftment failure correlates strongly with mortality. Layering in the platelet issue means my own immune system would have difficulty recovering on its own after engraftment failure. If the cancer were not so aggressive, I would likely not be taken to transplant with this issue. Yet again, the risk in simply attempting to keep BPDCN at bay without resetting my immune system overrides the risk of a potential failed transplant.
The second issue is that my antibodies may cause more severe graft vs. host disease (GVHD) after transplant. GVHD is the opposite of engraftment failure and is much more common. It occurs when the new immune system attacks my body as foreign. Most hematologists say that a little bit of GVHD is good because it means the new immune system is likely having the intended graft vs. leukemic effect of attacking and eradicating the cancer cells. GVHD can be as mild as a rash, but can be much more severe and lead to death. GVHD joins relapse as one of the two leading causes of mortality after bone marrow transplant. So, the fact that my antibodies put me at higher risk for more severe GVHD is, frankly, very scary.
Notwithstanding these risks, at the end of the day, BPDCN is the biggest elephant in the room. My best chance at a cure is still a successful bone marrow transplant that resets my immune system so that it can efficiently take care of the cancer cells on its own. Without a transplant, I will relapse and have no chance at long term survival. No risk, no reward.
I plan to update the blog again soon before my hospital admission next Tuesday so you can follow along with my pre-transplant treatment schedule. Please continue to pray for me, my family, and my medical team as we get ready to tackle this next phase.
With love,
Rebecca
