They "very promptly respond" to tiny whiffs of data when they suggest there is more money to be made (i.e. growing the pie of medical spending).
If the data suggest that a treatment in general use is in fact useless, they are blind.
https://www.theatlantic.com/health/archive/2017/02/when-evid...
https://mobile.nytimes.com/2016/08/04/upshot/the-right-to-kn...
Why do you think that? Medicine is one of the most data-driven industries out there, and usually very promptly responds to new therapies, etc. Particularly for cancer.
I'm not sure what you're thinking of with regards to this.