Percentages

April 7, 2024

When you get cancer, you immediately start getting lots of information. It can be overwhelming. Information about your diagnosis, your treatment, possible outcomes, where the infusion clinic is, possible side effects, your doctor's name (or many doctors), etc. It goes on.

One thing you start hearing a lot are percentages: overall survival rate, disease free survival rate, progression-free survival rate, relapse rates, the list goes on. Rightly or wrongly, these percentages can become a shorthand to understand how serious things are or could get. But like all statistics, they are prone to being misused. I've certainly misunderstood them and I hear friends and family misunderstanding them as well. So, an attempt to clarify.

To be clear, right now I'm in remission and have been since June, 2023. But once you are in remission, you face the prospect of relapse. So, every cancer has a "relapse rate."

Every cancer has different relapse rates. My cancer is Diffuse Large B-Cell Lymphoma ("DLBCL"). When I was diagnosed, I was Stage IV because the cancer had spread to both sides of my diaphragm (all my lymph nodes) as well as an organ outside my lymphatic system (one of my testicles). The spread of cancer to my testicle, an immune privileged site (as opposed to a different organ) is a troubling factor because it means there is a higher risk the cancer one day going to my brain ( another immune privileged site). There are also different DNA variants of DLBCL. Through gene expression profiling, it was discovered that I have one of these rearrangements (the ABC-type). This further heightens the risk of brain involvement. While lymphoma isn't rare, my diagnosis is fairly rare because of the testicular involvement and DNA rearrangement.

For people with my diagnosis (DLBCL, Stage IV, testicular involvement, ABC rearrangement), the five-year relapse rate is around 50%. The most common way this stat is misused (which I did myself) is to say "Josh has a 50% chance of relapse." That's not right. What the relapse rate means is that of the people with my diagnosis, 50% experience relapse within five years. It does not that I'm rolling 2d10 every day to see if I relapse. Whether I relapse or not isn't a percentage chance - it either will or will not happen. It isn't binary like this because of the 50% relapse rate. Rather, my dice have already been rolled behind the DMs screen. If the relapse rate was just 20%, my experience would be the same. I'm just waiting to find out the result.

This makes it simultaneously both easier and more difficult to carry on a daily basis and often why everything feels big. Some days I barely think about cancer. Some days it is all I can think about. Certainly if the relapse rate for my diagnosis was 5%, I'd probably think about it less. But that's not my lot. So, the next four years and three months, I'll get bloodwork and scans of one type or another every three months. And at some point I'll learn what my dice say.