Jenna asked if I could elaborate on what could have caused the secondary cancer I'm now facing. I'll do the best I can to answer using what I've been told over the last 5 years of post-transplant follow-ups. Please keep in mind that I have no medical training.
After a bone marrow transplant, survivors are placed on a drug regimen to keep their new immune systems in check. The transplant recipient's organs are in danger of being attacked by the new immune system, when this occurs it's called Graft versus Host disease. It can be a very mild event manifesting in a persistent rash, or it can be life threatening and affect the lungs or liver. I've been on both ends of the spectrum and have suffered from GvHD of the eyes, skin, scalp, liver, lungs, and mouth.
I take tacrolimus, an immunosuppressant, which hobbles my donor's overactive immune system. It's meant to keep my organs safe. Mostly, it works, but when my liver and lungs were under attack, I needed high-dose steroids. Prolonged use of tacrolimus can lead to a host of problems which include secondary cancers. Prolonged use of any medication can lead to problems down the road.
Squamous cell carcinoma is the most common secondary cancer that afflicts bone marrow transplant survivors. As I understand it, the cancer usually manifests on the skin, usually on the face.
Here's where things get shady. Just because you have had a transplant and have taken an immunosuppressant doesn't guarantee that you will develop a secondary cancer.
The presence of Graft versus Host disease of the skin or mouth has been linked to an increased chance of developing skin or oral cancer. I've suffered from both since the first transplant. It comes and it goes with no warning. I've been seeing a dermatologist who specialized in GvHD of the skin. She checks me once a year for skin cancer.
I'm a little over 4 years out from the second transplant. The GvHD affecting the tissues of my mouth has been fairly persistent and is one of the reasons I suspect my transplant doctor of adding the head and neck oncologist to my stable of specialists. It's an if then maybe proposition.
There's no clear-cut reason for why this happened, just a jumble of incidences that added up to a bonus cancer.