Barnes told The Associated Press on Tuesday that he went through five weeks of radiation treatment beginning in January and had surgery to implant radioactive seeds in March. The Democrat from Marietta says a fresh round of tests is set to determine whether the cancer is gone.
Barnes said he learned he had cancer from a routine physical last year after his failed comeback bid for governor.
Doctors told him he caught the problem early and he urged other men to make sure they are tested routinely after age 50.
Barnes was elected governor in 1998 and served one term. He was defeated by Republican Nathan Deal last year in a GOP sweep in Georgia.