Yes. There is a long association between sweeteners and cancer. There are newer ones tha may be better since not truly artificial.
Not generally. Artificial sweeteners are considered to be generally safe, and may provide an overall health benefit compared with excess calories. Animal studies have implicated artificial sweeteners as a cause of bladder and brain tumors, but very large epidemiological studies have failed to confirm this risk. One study suggested an increased risk of decreased kidney function, but this has not been confirmed.