I would not run cardarine long term. I am not running it anymore.
I would use it sparingly for a very specific purpose / goal.
I would highly suggest looking into the cancer aspect further. There is literature that suggests it is carcinogenic, and literature that suggests it has anti-cancer effects.
I do not understand cancer well, so, take what I say with a grain of salt. It seems to accelerate some cancers and seems to help reduce others. Seems like it may be context dependent. Also seems to spur the development of cancer, not just accelerate existing
I'm talking out of my ass now but perhaps due to its shifting of metabolism (fat vs sugar), it might cause certain cancers that live off sugar vs fat to accelerate / decelerate.
In summary, do your own research and diligence deeply, because I dont think the cancer risks are to be ignored. However, I think they may be overblown in some cases.
Having said all of this, I wish I used less of it over the years since I will never know if it could play a contributing role in me developing / accelerating cancer.
I would rather gamble on GH and it accelerating cancer than gamble on cardarine long term and cancer.