Elephants are massive, and have a very large number of cells compared to humans, yet their rates of cancer aren't higher than ours. Research indicates that it may be due to TP53, a cancer suppression gene that is repeated a ton in the elephant. I could see anti-aging therapy eventually being used in conjunction with gene therapy to strengthen our own tumor suppression capacity.

The body, when it is healthy, generally kills cancerous cells on its own. This is, from what I understand why many cancers come with sickness/age, because your body doesn't react as robustly to broken cells as it did in health and youth. Something like "age reduction" could end up being a cure for many cancers, one could think.

Given that there are cancer's that strike the young as well, I don't know if that would actually work out.