Jewett staging system: A system for determining the stage of a prostate cancer. The system uses ABCD. The letters "A" and "B" designate cancers that are confined to the prostate. The letter "C" applies to cancers that have grown out of the prostate but have not yet metastasized (spread) to lymph nodes or other sites. And the letter "D" refers to prostate cancer that has spread to lymph nodes or to other sites.