[api]

There is a school of thought in anti-aging research that some of the mechanisms of aging, such as telomeres, are adaptations to prevent cancer. So evolutionarily there might have been a life span / cancer risk trade-off. This of course would have been optimized to maximize long-term reproductive success, providing a long enough life span to have, raise, nourish, and educate children while minimizing the risk of dying of cancer along the way.

It's likely that aging is a product of multiple such trade-offs. I very, very strongly doubt that SENS will be achieved by simply adjusting one or two knobs.

One possibility is that we just get really, really, REALLY good at detecting and zapping cancer, and then we turn off all the senescence-generating anti-cancer safety switches and decay mechanisms and just play whack a mole with the cancers when they arise. So you get to live two or three times as long but you're in for cancer removal at least once per decade.

[im3w1l]

It'd be nice if we could proactively repair DNA to prevent cancer from arising.

[CmonDev]

"...maximize long-term reproductive success..." - where 'long-term' means 30 years based on observable health decline. We have to switch to metal bodies or something.