Experience with Gleason's histopathologic grading in prostatic cancer.

The inaccuracy of clinical staging as a predictor of the biologic potential of prostatic cancer has prompted evaluation of additional methods of assessment. We reviewed 228 patients with prostatic adenocarcinoma who presented during a 4-year period. Of the 228 patients 144 with no detectable bony disease underwent staging pelvic lymphadenectomy with or without preliminary bilateral pedal lymphangiography. Histopathologic specimens of the primary diagnostic prostatic biopsy were classified with Gleason's grading system of tumor differentiation. Of the patients with Gleason's sum of 8, 9 or 10, 93 per cent had regional nodal metastases, regardless of preliminary clinical stage. Furthermore, no patient with Gleason's sum of 2, 3 or 4 had nodal metastatic disease. The incidences of falsely positive and falsely negative lymphangiograms were 29 and 35 per cent, respectively, reflecting the unreliability of pedal lymphangiography to predict nodal involvement accurately in patients with prostatic cancer. The Gleason system of histopathologic grading was reliable and reproducible, and afforded an accurate prediction of the surgical stage of disease.