Histopathology of localized prostate cancer. Consensus Conference on Diagnosis and Prognostic Parameters in Localized Prostate Cancer. Stockholm, Sweden, May 12-13, 1993

Abstract

Future handling of patients with localized prostate cancer will undoubtedly depend upon a more sophisticated prognostication than that available today. The basis will continue to be the histopathological evaluation of tumor size, grade, localization and distribution within the gland. The aim of this section is to summarize current concepts of the morphological characteristics of localized prostate cancer and their prognostic implications as well as to give guidelines for standardization of the methods involved in morphological evaluation. First, baseline recommendations for the tissue processing procedures are given: Needle core biopsies, taken in a systematic way, potentially contain the information necessary for estimation of grade, size, distribution and extension to seminal vesicles, and could yield material for DNA-measurements, cytogenetic and genetic information. For TUR specimens it is suggested that at least 10 grams should be embedded or 8 to 10 cassettes employed minimally. The prostatectomy specimens should be carefully examined. Material should be frozen both from tumor tissue and from other areas eg by taking 'mapping' biopsies in a standardized way. After fixation (in 10% buffered formalin for at least 24 hours) and appropriate inking of surgical margins, whole mount sections at 2.5-5 mm intervals should be cut. The extension of the tumor should be outlined and at least the two largest tumors should be graded. Capsule penetration and extension to surgical margins and seminal vesicles should be indicated. Grading of malignancy should always include the Gleason grade and where possible Gleason score (ie the sum of the dominant and the secondary grade or pattern). The WHO and the Boecking systems combine a grading of glandular architecture with a grading of the nuclear atypia. It is stressed that in core biopsies the amount of cancer is sometimes scanty, which limits the possibility to find dominant and secondary patterns. In such cases, a grading of glandular differentiation and of nuclear grade seems rational. Also, for comparison with cytological grading, the WHO system is suitable, since in both cases both tissue differentiation and nuclear atypia are judged. The future need for objective techniques is recognized. Prostatectomy pathology includes important features with high correlation to postoperative prognosis: eg capsular penetration. The extent of capsular penetration and the extent of involvement of the surgical margins is of importance. Only focal penetration or focal involvement of the margin carry a relatively low risk of of progression.(ABSTRACT TRUNCATED AT 400 WORDS)