A recent exchange with a blog reader/myeloma patient list member made me rush to re-read and re-post about a 2007 Mayo Clinic study titled “Clinical Course and Prognosis of Smoldering (Asymptomatic) Multiple Myeloma” (the full study is now available: http://tinyurl.com/c9f8lb).
It is based on a review of Mayo Clinic smoldering myeloma patients whose risk of progression to active myeloma was calculated at 10% per year for the first 5 years, 3% for the next 5 years and 1% for the last 10 years (“last”? Hmmm…). But read this: the cumulative probability of progression was 73% at 15 years.
I knew about this study, I even posted about it after it was published, but, I confess!, back then, for some inexplicable reason, I completely missed what I now consider to be one of the main points: the cumulation business. Okay, I am hardly a math genius…never was, never will be. But I must also have been in denial at the time, because the study spells it out…very clearly…as we will see.
First, another admission: I probably would have paid more attention to this study if it had focused on my own age group, give or take a few years, in a similar state of, uhm, good health. I have always been very very (very!) wary of statistical studies…there is so much missing information, blablabla. I find these studies interesting, but that’s where it ends.
Anyway, point is, what I remembered about the study’s percentages was totally wrong. I thought that after 5 years spent in a smoldering state, the risk of progression to active myeloma went down to 3%. Well, sure, technically that is what happens, according to the Mayo study, but it’s not that simple.
It’s not as though you begin each smoldering year from scratch. With every year that passes, in fact, you have to add the risk percentage that you accumulated in previous years. My blog reader set me straight on this point: the progression risk is cumulative. That means that after, say, six smoldering years, your risk of progression is as follows: 10 x 5 = 50 + 3 = 53%. Oh boy, there is quite a difference between 53 and 3%!
Let’s see, based on this study’s group classification, I would be in group 1. So, now that I am in my fourth smoldering year (as far as I know), my present risk of progression to active myeloma would be about 40%. Not too staggering. But what shocked me for a split second is this: even if my overall risk percentage drops from 10% to 3% next year, my cumulative risk percentage could reach 90% in 2020. 90%??? A question popped into my head as I read that: has anybody gone beyond the 100% threshold? Okay, that’s my goal now…to pass that threshold…!
Another thing caught my eye: The median time to progression was 2 years in group 1. Well, I am way past the median point…I have been in group 1 (in fact, a couple of times I even jumped into group 2, a “better” group in terms of progression risk) for 3.5 years, now, so I have beaten the median time, at least.
You can read the study on your own and, if you are smoldering, figure out what your risk of progression might be. Or…not. You see, I am not at all sure that I am better off knowing about this cumulative business. I think I might have preferred to have lived the rest of my life in blissful ignorance of the…dangers of progression.
But statistics are just numbers, after all…and numbers can be beaten. And, as my case shows, median times can certainly be beaten!
In conclusion, based on conventional medical statistics, my progression percentage seems to be much higher than I thought (er, if I even thought about it at all…!). So, the question is: am I worried about progressing to active myeloma? Uhm, let’s see now, I will have to get back to you on that one in the year 2029…or 2039…or…