You have to be careful not to cause cancer in the process.

From what I read, a lot of the things the body does, which have aging as a side effect, are intended to block cells from becoming cancerous.

For example a senescent cell - it might be damaged, and if it dived it might become a cancer, so better stop it from dividing. But we still need it, so don't kill it off.

Now you might think - actually, let's kill it and let some other cell divide and replace it. But that creates more cell division, which are more opportunities for cancer.

Basically, it's a delicate balance.

I suspect a different balance is also possible (there are animals without cancer for example), but the hard part is you must change all the parts at once (into the new balance), and simply stopping one part of the process will cause cancer.

This is going to make the research very hand without truly understanding all the moving parts, and joining all the different treatments into a single working whole.

What's needed is a fast-living animal, that ages, and gets cancer, in the same way humans do. Then you can just experiment without understanding.