The cancer death rate had its largest one-year decline ever from 2016 to 2017, falling 2.2 percent, according to a new study.

The decline in the death rate from cancer is due in part to advances in a new form of treatment called immunotherapy, which trains a person’s immune system to fight cancer, said Dr. William Cance, chief medical and scientific officer for the American Cancer Society.

Between 1991 and 2017, the cancer death rate fell by 29 percent, the report finds. That drop translates to 2.9 million fewer cancer deaths than if the rate had stayed steady, the report says.

Read more at The Hill.