“A rule of thumb is a homemade recipe for making a guess. It is an easy-to-remember guide that falls somewhere between a mathematical formula and a shot in the dark…”
So says the website dedicated to the principle, “Rule of Thumb.org.
Who knew? I thought that it was just an expression.
Yesterday I mentioned how I had asked both of my myeloma docs about “the half-life effect,” which is nothing more than an oncology related rule of thumb.
Once most cancers become drug resistant, even new, otherwise effective therapies tend to work for a shorter period of time.
This is especially true with multiple myeloma.
Whether it is following a stem cell transplant or long term maintenance therapy with drugs like Thalomid, Revlimid and/or Velcade, once a patient relapses, the “rule of thumb” or “half-life effect” when working with multiple myeloma survivors works like this:
Once relapse occurs after a stem cell transplant, doctors in the know would only expect a remission following a second transplant to work for half as long.
The same general “rule” applies to patients who have never had a transplant. Once a therapy stops working, the averages say that the next therapy regimen will also only work for half as long.
As a general trend, this may in fact be true. But let’s remember that a rule of thumb is nothing more than a good guess.
Remember my post about Loren Liedl ten days ago? “Living nine months at a time” is a great example of how rules of thumb are unreliable and meant to be broken.
No matter what the therapy–stem cell tranplants, Thalomid, Revlimid, Velcade or toward the end, a mix of every possible anti-myeloma concoction anyone could imagine–each therapy only worked for Loren for around nine months.
My good friend lived 14 years that way–jumping from clinical study to auto transplant to novel therapy agent–flying in the face of the myeloma half-life rule of thumb.
I’m sure all of us know someone who has beat the odds and have had a therapy or therapies work longer (or much shorter) than expected.
So how do physicians explain it when their expectations don’t meet reality?
Tune-in tomorrow and let’s examine this more closely.
In the meantime, remember the mantra of any long-lived multiple myeloma patient and repeat after me:
I’m not a statistic. I’m not a statistic…
Feel good and keep smiling! Pat