Re: Why do cancer drugs get such an easy ride?
It is salutary to be reminded that the 71 drugs for solid tumours approved by the FDA over the last 12 years prolong life by a median of only 2.1 months. The performances of individual drugs within this population will follow a distribution: we are not told the performances of those which appear in the upper 25th or 10th centile but these drugs may be judged worthwhile, once properly attested, by the medical profession or society as a whole.
As a physician, I also used to discuss treatment in terms of median response or survival. I am now retired and suffering cancer for the third time myself. In each encounter I have scrutinised survival curves, and the effects of proposed treatments on them where known. I have noted that the usual exponential decline in survival has levelled off in each case at a point above zero, whence the slope levels and may approach that in an age-matched population. In other words, there are always some long term survivors. And I ask myself “why should I not be in that group? Someone has to be”.
For my stage 3 adrenal cancer, for example I noted that the median survival (with and without surgery and adjuvant mitotane) was nine months, but that around 15% of the study population were still alive when published observation ceased at five years. That was in 2008. In 2012 I was treated for stage 2a gastric cancer. It is now clear that my progression-free survival from gastric cancer since then has proved well below median: I have relapsed with a large single metastasis and am more optimistic than the trials of palliative chemotherapy would support.
Of course the numbers still under observation at the end of a trial are always, inevitably, very small and the confidence intervals around them almost uselessly large. This justifies a plea for longer follow-up and routine second publication. The point I really wish to make is that treatments may offer similar median, but quite different upper 10th or 5th centiles, for prolongation of survival. Maybe their approval should be judged with both statistics in mind, and the patient offered an appropriately balanced chance to be optimistic.
Competing interests: I am the patient (as is clear)