Bostwick D G
Department of Pathology, Mayo Clinic, Rochester, MN 55905, USA.
Cancer Surv. 1995;23:7-18.
"Incidental" cancer refers to predominantly well differentiated cancer that arises in the transition zone and is found by chance in TURP chips. These tumours are frequently small and may be completely resected by TURP, although a significant number have an additional tumour that is unreachable with a resectoscope. These tumours often co-exist with benign prostatic hyperplasia. Putative precursors of incidental carcinoma include high grade PIN and AAH, and these lesions are frequently found in the transition zone in prostatectomies for cancer. The single most significant question in treating incidental adenocarcinoma is how to separate tumours that will progress from those that will not progress during the expected lifetime of the patient. The 1992 revision of the TNM staging system separated non-aggressive (T1a) and aggressive (T1b) incidental cancer according to the number of foci of cancer, using more than three foci as the cutpoint to identify more aggressive cancer. However, 8-37% of patients with T1 a cancer will develop cancer progression within 10 years if untreated, with the risk of progression increasing with additional years of follow-up. Important prognostic factors include the patient's age, tumour location (peripheral zone v. transition zone), tumour grade, tumour volume, serum PSA concentrations and morphometric factors such as nuclear roundness. Studies directed at early detection allow discovery of increasingly smaller cancers.
“偶然发现的”癌症主要指起源于移行带的高分化癌，在经尿道前列腺切除术（TURP）的组织碎片中偶然发现。这些肿瘤通常较小，可通过TURP完全切除，尽管相当一部分还有经电切镜无法触及的额外肿瘤。这些肿瘤常与良性前列腺增生并存。偶然发现的癌的假定前体包括高级别前列腺上皮内瘤变（PIN）和非典型腺瘤样增生（AAH），在前列腺癌前列腺切除术中，这些病变常在移行带发现。治疗偶然发现的腺癌最关键的问题是如何区分在患者预期寿命内会进展的肿瘤和不会进展的肿瘤。1992年修订的TNM分期系统根据癌灶数量区分非侵袭性（T1a）和侵袭性（T1b）偶然发现的癌症，以超过三个病灶作为切点来识别侵袭性更强的癌症。然而，如果不治疗，8% - 37%的T1a期癌症患者在10年内会发生癌症进展，随着随访年限增加，进展风险也会增加。重要的预后因素包括患者年龄、肿瘤位置（外周带与移行带）、肿瘤分级、肿瘤体积、血清前列腺特异抗原（PSA）浓度以及形态学因素如核圆形度。针对早期检测的研究使得越来越小的癌症得以发现。
