Bostwick D G
Department of Pathology, Mayo Clinic, Rochester, MN 55905.
Am J Clin Pathol. 1994 Oct;102(4 Suppl 1):S38-56.
Histologic tumor grade is a strong predictor of outcome for men with prostate cancer. All existing grading systems successfully identify well-differentiated cancer, which progresses slowly, and poorly differentiated cancer, which progresses rapidly, but they are less successful in subdividing most moderately differentiated cancers, which have an intermediate malignant potential. The Gleason system, the de facto standard for grading, identifies histologic patterns by the degree of glandular differentiation without relying on morphogenetic or histogenetic models; it reflects tumor heterogeneity by combining primary and secondary patterns into a cancer score. Modifications that have been proposed for Gleason grading include morphometric nuclear grading, grouping of grades, estimating the amount of high-grade cancer (Gleason patterns 4 and 5), and including the cribriform pattern as Gleason pattern 4 rather than 3. Most variants of prostate cancer are high grade (Gleason patterns 4 and 5), including small cell undifferentiated carcinoma, signet ring cell carcinoma, sarcomatoid carcinoma, and carcinosarcoma. The Gleason system can be reproduced by most investigators, although there is a small but significant level of interobserver and intraobserver variability that is unavoidable. When compared with matched prostatectomy specimens, contemporary 18-gauge needle core biopsy underestimates tumor grade in 33% to 45% of cases and overestimates grade in 4% to 32% of cases, similar to results with traditional 14-gauge biopsies. Grading errors are common in biopsy specimens with small amounts of tumor and low-grade tumor, and are probably due to tissue sampling error and tumor heterogeneity. Upgrading of prostate cancer may occur after radiation therapy but is common after androgen-deprivation therapy. Univariate and multivariate analyses of prognosis in prostate cancer almost always identify cancer grade as one of the most significant predictors of patient outcome. The combination of cancer grade with other prognostic variables to create a multiple prognostic index should allow greater precision in predicting outcome for individual patients.
组织学肿瘤分级是前列腺癌男性患者预后的有力预测指标。所有现有的分级系统都能成功识别分化良好、进展缓慢的癌症，以及分化差、进展迅速的癌症，但在细分大多数具有中等恶性潜能的中度分化癌症方面则不太成功。格里森系统是分级的实际标准，它通过腺管分化程度来识别组织学模式，而不依赖于形态发生或组织发生模型；它通过将主要和次要模式合并为癌症评分来反映肿瘤的异质性。对格里森分级提出的修改包括形态计量核分级、分级分组、估计高级别癌症（格里森模式4和5）的数量，以及将筛状模式列为格里森模式4而非3。前列腺癌的大多数变体都是高级别（格里森模式4和5），包括小细胞未分化癌、印戒细胞癌、肉瘤样癌和癌肉瘤。尽管存在不可避免的观察者间和观察者内的小但显著的变异性，但大多数研究者都能重现格里森系统。与匹配的前列腺切除标本相比，当代18号针芯活检在33%至45%的病例中低估了肿瘤分级，在4%至32%的病例中高估了分级，这与传统14号活检的结果相似。分级错误在肿瘤量少和低级别肿瘤的活检标本中很常见，可能是由于组织取样误差和肿瘤异质性。前列腺癌在放疗后可能会升级，但在雄激素剥夺治疗后很常见。前列腺癌预后的单变量和多变量分析几乎总是将癌症分级确定为患者预后最重要的预测指标之一。将癌症分级与其他预后变量结合起来创建一个多预后指数，应该能够在预测个体患者的预后方面实现更高的精确性。
