The position they've taken is that they want to shift cancer funding from treatment to prevention. I have no idea whether this makes any sense or if it will actually happen but that is the current messaging.
There is no prevention strategy that will prevent all cancers. Even people with the most healthy lifestyle can get a cancer. That's why you have to do both.
Just to give one example: the majority of men will get prostate cancer if they live long enough (~70% of men over 80). It's just that other things tend to kill people before the cancer.