Isn’t it the case that the average size of an organism (at least in mammals) correlates a lot with lifespan and cancer rate?

Elephants and whales get cancer much less than humans and humans get it much less than rats. If cancer mutations are a dice roll than the more cells an organism has the more “will I become cancerous” rolls happen, so larger organism had to evolve better mechanisms to kill cancerous cells before they get out of control.