Histological grade, perineural infiltration, tumour-infiltrating lymphocytes and apoptosis as determinants of long-term prognosis in prostatic adenocarcinoma.

A series of 325 prostatic adenocarcinomas with a long-term clinical follow-up were subjected to light microscopic analysis of histological prognostic factors, including three grading systems (Gleason score, WHO grade, nuclear grade), perineural infiltration of the tumour (PNI), tumour infiltrating lymphocytes (TIL) and the presence of apoptotic cells (APO). All three histological classifications correlated significantly with the prognosis, but in multivariate analysis, the Gleason score was superior to the WHO grading or nuclear grading in predicting patient survival. PNI was significantly related to poor differentiation of the tumour, its progression and ominous disease outcome, particularly in T1-2MO tumours. The density of TIL was independent of the tumour differentiation, and absent or weak TIL were signs of a high risk of tumour progression and of a fatal disease. Apoptotic cells were commonly detected in poorly differentiated tumours and apoptosis was related to disease progression and low survival probability. The results suggest that the Gleason score, PNI and the density of TIL should be included in routine pathology reports, to be used by clinicians while making therapeutic decisions in prostatic cancer.