Then why not respond appropriately, and stay aware of cancers but don't treat them until they reach some critical stage? I don't see how intentionally remaining ignorant is helpful.
Because if a localised cancer is destined reach later stages then getting treatment as soon as possible is of the essence - if you wait for it to become malignant before treating it the chances of survival go down.
Often it's impossible to tell right now which asymptotic localised cancers are going to eventually kill the patient if left untreated and which are going to be non-bothersome or even spontaneously regress. They look the same in many cases.
What would you do if your doctor found a cancer and refused to treat it? What do you think most people would do? I reckon most people would shop around until they found a doctor that would treat it. Even if they followed the doctor’s advice, the knowledge they have cancer might be incredibly stressful and distressing.
On a population-wide scale, ignorance may be the best option right now.
If my doctor said "Yes, this is cancer, but it's so small and more likely than not to never become a problem. Come back in two months and we'll check again to make sure it's not becoming a problem", then I would be fine with that answer.
