The only treatment that has large proven effects is calorie restriction[0] although that really lowers ones quality of life. Intermittent Fasting [1] seems to have many of the same benefits without being anywhere near as hellish.
3rd paragraph: "If you have a healthy diet low in sugar, high in antioxidants, in theory you can reduce DNA damage, keeping your DNA looking younger", etc...
Eat your leafy greens.
With respect to antioxidants, there had been mounting evidence recently that antioxidants could paradoxically increase cancer risk. The evidence so far is that there are cellular pathways that spool up in the presence of oxidants and can cause cells to undergo cell death. Antioxidants can hinder these pathways from firing and instead, allow cells to linger around longer than they should.
Slip-slop-slap (http://en.wikipedia.org/wiki/Slip-Slop-Slap), or just stay out of the sun as much a possible (do not stay in a bunker 24/7, as that would lead to vitamin D deficiency)