Cytological grading of therapy-induced tumor regression in prostatic carcinoma: proposal of a new system.

Proposed in this article is a new system for the cytological grading of therapy-induced regression of prostatic carcinoma. Reversible and irreversible criteria in cytoplasm, nuclei, and nucleoli are distinguished and rated independently of each other on a scale of 0 to 2; the cellular regression grades r1-r3 are the sum of rating numbers. Criteria that are invalid for grading regression are pointed out. Results of the clinical testing of this grading system are presented.