BY KATHY LATOUR | JUNE 12, 2013
When I first started reading studies, I remember reading one in particular and everyone was really excited about the fact that it offered an increase of four months of median survival time.
That didn't seem like a lot to me, until I understood what it meant.
Median survival means that there were some patients who lived much longer on the drug, and some who lived a much shorter time on the drug. To be more specific, four months of median survival time means that half of the patients on the treatment died before four months, but also that half of the patients lived beyond four months; some may have lived much longer than four months. Looking at the actual study can illustrate this effect.
Also, unless you have the whole study in front of you, what you don't know is how sick the patients were who took the drug, and that's important. New drugs are often given to patients who have no more options for the obvious reason that they are not going to give an experimental drug to a patient who could get some response from a drug that has shown efficacy.
Another aspect you have to take into account is the patient. What we are learning is that in each group of patients who take a drug, there may be one or two who respond very well. For some reason unknown to anyone, one or two patients may have a great reaction to the drug and their cancer may go into remission or reduce in size.
When these cases are thrown in with the others, it skews the results, but it also makes news and sometimes results in the study being stopped early so the drug can be given to more patients who have one or two similarities that indicate they may respond to the drug.
Right now researchers are trying to find those small pools of patients who respond to certain drugs and single them out. It's the reason that many patients now get a cocktail of chemotherapy drugs instead of just one. They may have one drug that covers all dividing cells and then one that only targets a particular protein known to help that one kind of cancer grow. It gets very complicated.
So, when you hear of a drug showing a median of three months of extended life, look at the surrounding information in the study. Did one patient live a year? Did one have a remarkable response that calls for further investigation?
You may remember the big noise around Avastin when the powers that be wanted to remove it from metastatic breast cancer use. Well there is a subset of women for whom Avastin works wonders. They didn't want it removed for obvious reasons. But there are very few of them.
And as my friend Suzanne Lindley says, even if it is only six months you get, that's half a year and two seasons to watch a 4-year-old begin to notice new things in her life and have new memories. Six months is a lot of live when you are facing not having it.RELATED POSTS