From what I understand, the study had 3 groups: mice given a carcinogen, mice given Cardarine, and mice given a carcinogen and Cardarine. Both groups that did not contain the mix had 0% incidence of cancer while the group that received both the carcinogen and Cardarine had a 100% incidence of cancer. The problem is the doses of Cardarine given to the mice were insanely high and for an extremely prologned period compared to a cycle a human would run. I've read a couple studies where in vitro treatment of human cells with Cardarine did not accelerate the growth of cancer nor did it cause cancer.
I don't know much about PPAR agonists, but from my understanding, they cause all cells to grow faster. So it would accelerate cancer growth theoretically if someone already had cancer cells present in their body. But then I've read stuff saying that the receptors Cardarine acts on are present in much lower quantities in cancer cells, meaning that Cardarine would (for the most part) be able to selectively target normal cells instead of cancer cells.
The benefits, on the other hand, look insane. Great increases in energy and cardiovascular endurance as well as improved nutrient partioning and anti-catabolic properties. All this without messing with the HPTA axis at all. I hope this can spark a discussion over the current literature as most of the info I find is over 2 years old. It seems more recent studies have leaned toward Cardarine being very safe, but obviously the jury is still out or it would be a prescription only substance here in the states.