Sunday, December 11, 2011

Stem Cell Transplants 101: What's the plan?

I realize that for most people the news that "I'm getting a stem cell transplant" is about as meaningful as me saying "I'm having my naruffula collar removed" (which is to say that it sounds concerning, but doesn't mean a lot). This post is meant to serve as a sort of introduction for non-medically oriented friends and family, who would like to understand what this process will entail.

For starters, the stem cell transplant is not the first step in the process. I have to go through preparatory treatments (and those have to be working) before we move forward with the transplant itself. In the past, these treatments have always come in the form of chemotherapy. (Definition: Chemotherapy is basically poison that is most effective against cells that reproduce quickly, like cancer cells, hair cells, and the cells that line the interior of your mouth. That's why many people on chemo lose their hair and/or get mouth sores. But it is poison, so it makes people nauseous and feel cruddy). For my first transplant (Dec '09) I tried one prep regimen of chemo that ended up not being totally effective. We had to switch to a different sort of chemo, which shrank my cancer some but not completely. That was enough to move forward with the first transplant though.

Luckily for me there is a new treatment for Hodgkin's patients who have relapsed after an autologous stem cell transplant. (Definition: Autologous stem cell transplants are transplants where a patient's own stem cells are used, like my first transplant. These are less dangerous than Allogeneic transplants, which are transplants where the patient receives a donor's stem cells, like my upcoming transplant). The new drug that is available for treatment is called adcetris and it's only been available for the last 2-3 months. It was fast-tracked through the FDA's drug approval process after showing promising results in clinical trials (30% of patients had their cancer shrink down to nothing, another 42% had their cancer shrink somewhat). The great thing about adcetris (in addition to having good results) is that it is NOT chemo. This drug is a monoclonal antibody. (Definition of Monoclonal antibody: Your guess is as good as mine). So I'm not sure exactly what that means, but it's not poison and my doctor assures me that it will be the easiest treatment regimen I've been on so far. Since it's not chemo, I shouldn't have all the cruddy side effects associated with chemo. I'll get the drug once every three weeks. It only takes 1 hour to administer the drug, and then I'm finished until 3 weeks later when I go in for another dose. I'm also excited because this leisurely treatment schedule means the doctor probably will allow me to go through it without getting a port again. (Definition: A "port," or more correctly a portacath, is a small device that sits under one's skin and provides easy access to a vein. It feels like a MicroMachine lodged under your skin. Doctors and nurses can stick a "needle" in it, which Brynn calls a "nail," to administer medicine or fluids, or to draw blood. It's handy if you need to get stuck a lot, but for me it probably won't be worth it this time around).

My port, version 1.0 (in use). I'm hoping to avoid the 2.0 install.
We'll do 3 rounds of the adcetris (so for 9 weeks total) and then we'll do another PET/CT scan. (Definition: A PET/CT scan is an imaging scan that helps the doctors see where the cancer is and if it is growing or spreading. They inject radioactive sugar into my blood, which is mostly absorbed by rapidly reproducing cells, like cancer. Other kinds of cells that reproduce rapidly can absorb the sugar, like scar tissue, which leads to a false positive. Then I'm put in a machine that takes thousands of images of my body and shows where radiation is coming from. Since the cancer cells absorbed the sugar, and thus the radioactivity, they show up on the scan).

(Option 1) If that PET/CT shows continued growth of the cancer, we'll scrap the adcetris and try a chemo prep regimen. (Option 2) If the cancer has disappeared, we'll move forward with the transplant. (Option 3) If the PET/CT indicates that the cancer is shrinking but is still there, we'll continue with additional rounds of the adcetris and then reassess with another PET/CT scan at a future date.

Once we've shrunk the cancer down it will be time to move on to the stem cell transplant itself. Even if the adcetris eliminates the cancer altogether, the Hodgkin's might come back without the stem cell transplant. The transplant starts with a huge, HUGE dose of chemo. A dose SO huge, it completely kills my entire immune system. The hope is that the chemo kills off any remnants of the cancer, wipes my immune system clean, and we start with a blank slate. The problem with that, is that without an immune system I'd be a goner. Seriously, if we took no other steps after the "killer" chemo, I would die. This is where the stem cells come in. My body still hasn't fully recovered from the first transplant, so it's not making enough of its own stem cells for me to provide my own for the transplant. That's why I need a donor. So after the "killer" chemo has done its job and I have zero immunity to any germ in the world, I will receive the gift of life (aka. stem cells) from a donor. (Note: It is the chemo that might, fingers crossed, cure the cancer. The stem cells just repair my body after the chemo has devastated it).

***Revision 3/14/12: In an allogeneic transplant the above description isn't quite right. In my case I will receive an intermediate dose of chemo before my transplant which will take my immune system down very low. I will receive donor cells and grow a new immune system (which will be the donor's immune system). The hope is that the new immune system recognizes any future cancer growths as abnormalities and attacks them. So the part above about the killer chemo being what eliminates the cancer is wrong. In an allogeneic transplant we're counting on the donor's immune system to keep any future cancer in check.***

Those stem cells will be infused into my body just like I was getting a blood transfusion. It's really kind of anti-climactic, and the nurses say everyone smells like creamed corn on the day of their transplant. Those stem cells are the building blocks for a brand new immune system for my body. But it takes a long time for that new system to be built and begin to work. In the interim, the danger is that I might get sick. With no immune system my body is entirely susceptible to any germ that comes near it. I have no defenses. The doctors can treat me with antibiotics, but often times that's not enough. Many people who receive transplants die from infections that they couldn't overcome.

One of the bags of my stem cells. Looks unexciting, saved my life.
From beginning to end the transplant itself, which is all spent on one hallway of the hospital, takes anywhere from three and a half to six weeks. Possibly longer with complications. Patients are terribly bored and many are depressed. Children under 14 aren't allowed on the floor at all, ever, for any reason. During my first transplant that meant I did not see Brynn for over 4 weeks, which included Christmas. I watched her open her presents via Skype. It was tough, but I knew that getting that transplant was the only chance I had of celebrating many, many more Christmases with her. I'm disappointed that it failed, but I'm committed to doing whatever is necessary to be around for many more Christmases. If that means another transplant, then that's the plan.

**Disclaimer: I am not a doctor (obviously). This post is full of my best attempt to understand my own treatment and share that understanding with others. Please do not confuse this with a real medical explanation from a medical professional.

2 comments:

S. M. Curran said...

excellent post. makes a complex subject a lot more intelligible. xoxo sheila

Ashley said...

The way I understand it is that a monoclonal antibody, in this case, is specifically targeted to bind with the cancer cells and once it binds it can deliver a drug to the cell to kill it or just make the cancer cell more noticeable by the body so the bodies natural immune system will take care of it.

Mayo Clinic
"A monoclonal antibody is a laboratory-produced molecule that's carefully engineered to attach to specific defects in your cancer cells. Monoclonal antibodies mimic the antibodies your body naturally produces as part of your immune system's response to germs, vaccines and other invaders. "

http://www.mayoclinic.com/health/monoclonal-antibody/CA00082