Comment by photochemsyn

That could suggest why longevity in humans (or primates ) was under active selection, as they put a lot of effort into raising the children so you'd expect that cancer in younger people would result in the death of their children, so evolution selects for robust anti-cancer systems (like the human immune system, which is relatively good at detecting and eliminating cancer cells as well as pathogenic bacteria, etc.).

These explanations are however always a bit hand-wavy, eg why do galapagos tortoises live to 150 when they don't seem to do much parental investment?