Histologic grading study of prostate adenocarcinoma: The development of a new system and comparison with other methods—A preliminary study

A new grading system for adenocarcinoma of the prostate (MDAH System) and its simplified version, both based on the percentage of tumor that is differentiated (gland-forming) or undifferentiated (non-gland-forming), were compared with the grading systems of Mostofi and Gleason. In a study group of 182 patients with Stage C adenocarcinoma of the prostate, the MDAH system identified 84 patients (46%) as Grade 1, 75 (41%) as Grade 2–3, and 23 (13%) as Grade 4. Kaplan-Meier survival curves predicted a 91% five-year survival for Grade 1 patients, a 60% 5-year survival for Grade 2–3 patients, and a 15% five-year survival for Grade 4 patients. Wilcoxon (Gehan modification) tests showed that the survival was significantly different among Grades 1, 2–3, and 4. The MDAH System is an improvement over other grading systems in that it is a simple, low-power microscopic method that depends only on the percentage of gland formation in the tumor and further reflects the biologic behavior of the tumor as measured by the patient's survival.