Incidence of prostatic intra-epithelial neoplasia in Osaka, Japan

Preneoplasia in the prostate gland with emphasis on high grade prostatic intraepithelial neoplasia

There are a variety of morphological patterns and processes that have been implicated in the pathogenesis of prostate cancer. Prostatic intraepithelial neoplasia (PIN), inflammation with or without atrophy, and adenosis (atypical adenomatous hyperplasia) have all been given candidate status as precursor lesions of prostatic adenocarcinoma. Based on decades of research, high grade prostatic intraepithelial neoplasia (HPIN), a proliferative lesion of prostatic secretory cells, has emerged as the most likely morphological pre-invasive lesion involved in the evolution of many but not all prostatic adenocarcinomas. In this manuscript, we briefly discuss other proposed precursors of prostatic adenocarcinoma and then focus on the history, diagnostic criteria and morphology of HPIN. The incidence of HPIN and its relationship to prostate cancer is reviewed. The differential diagnosis of large glandular patterns in the prostate is discussed in depth. Finally, we summarise the recent clinicopathological studies evaluating the clinical significance of HPIN and discuss follow-up strategies in men diagnosed with HPIN.

Precursors of prostate cancer

High-grade prostatic intraepithelial neoplasia (PIN) is the only accepted precursor of prostatic adenocarcinoma, according to numerous studies of animal models and man; other proposed precursors include atrophy and malignancy-associated changes (with no morphologic changes). PIN is characterized by progressive abnormalities of phenotype and genotype that are intermediate between benign prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of prostatic carcinogenesis. The only method of detection of PIN is biopsy because it does not significantly elevate serum prostate-specific antigen concentration and cannot be detected by ultrasonography. The mean incidence of PIN in biopsies is 9% (range, 4%-16%), representing about 115,000 new cases of isolated PIN diagnosed each year in the United States. The clinical importance of PIN is its high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent carcinoma, especially when multifocal or observed in association with atypical small acinar proliferation (ASAP). Carcinoma develops in most patients with PIN within 10 years. Androgen deprivation therapy and radiation therapy decrease the prevalence and extent of PIN, suggesting that these forms of treatment may play a role in prevention of subsequent cancer. Multiple clinical trials to date of men with PIN have had modest success in delaying or preventing subsequent cancer.

Precursor lesions to prostatic adenocarcinoma

High-grade prostatic intraepithelial neoplasia (PIN) is the one well-documented precursor to adenocarcinoma of the prostate. This review article defines both low- and high-grade PIN. Unusual variants of high-grade PIN are illustrated. Benign lesions that may be confused with high-grade PIN, including central zone histology, clear cell cribriform hyperplasia, and basal cell hyperplasia are described and illustrated. High-grade PIN is also differentiated from invasive acinar (usual) and ductal adenocarcinoma. The incidence of high-grade PIN, its relationship to carcinoma (including molecular findings), and risk of cancer on rebiopsy are covered in detail. Finally, intraductal carcinoma of the prostate, a controversial entity, is discussed and differentiated from high-grade PIN.

Contemporary clinical management of isolated high-grade prostatic intraepithelial neoplasia

High-grade prostatic intraepithelial neoplasia (HGPIN) is a premalignant lesion associated with increased risk of coexistent cancer or delayed progression to carcinoma. Extended biopsy schemes have improved the ability to rule out concurrent cancers, increased the detection of isolated HGPIN and removed the routine necessity for immediate repeat biopsy. As the natural history of HGPIN is poorly defined, and no non-invasive marker allows monitoring of progression to cancer, routine delayed interval biopsy should be considered in all patients. In this article, we present an overview of the existing literature on HGPIN and a proposed strategy for clinical management.

High-grade prostatic intraepithelial neoplasia

High-grade prostatic intraepithelial neoplasia (PIN) is now accepted as the most likely preinvasive stage of adenocarcinoma, almost two decades after its first formal description. PIN has a high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent invasive carcinoma. The only method of detection is biopsy; PIN does not significantly elevate serum prostate-specific antigen (PSA) concentration or its derivatives and cannot be detected by current imaging techniques, including ultrasound. Most patients with PIN will develop carcinoma within 10 years. PIN is associated with progressive abnormalities of phenotype and genotype, which are similar to cancer rather than normal prostatic epithelium, indicating impairment of cell differentiation with advancing stages of prostatic carcinogenesis. Androgen deprivation therapy decreases the prevalence and extent of PIN, suggesting that this form of treatment may play a role in chemoprevention.

High-grade prostatic intraepithelial neoplasia and prostate cancer risk reduction

High-grade prostatic intraepithelial neoplasia (PIN) is the earliest accepted stage in carcinogenesis, possessing most of the phenotypic and biochemical changes in cancer without invasion of the basal membrane of the acini. The support for high-grade PIN as the main premalignant lesion of prostate cancer is based on several lines of evidence derived from prostate cancer animal models, epidemiological, morphological, genetic, and molecular studies. The incidence of high-grade PIN averages 9% (range 4-16%) in prostate biopsies, representing 115,000 new cases of high-grade PIN diagnosed each year in the United States. Performing saturation prostate biopsies to rule out any coexistent prostate cancer followed by every 3-6 month serial repeated prostate biopsies is currently the only way in which to manage patients found to have high-grade PIN. Medical therapy for high-grade PIN may easily become the mainstay treatment for high-grade PIN. Treatment of high-grade PIN appears to be of clinical benefit notwithstanding the potential for prostate cancer risk reduction. These clinical benefits would reduce morbidity, enhance quality of life, delay surgery or radiation, and increase the interval for surveillance requiring invasive procedures.

Prevalence of prostate cancer and prostatic intraepithelial neoplasia in Caucasian Mediterranean males: an autopsy study

BACKGROUND

The prevalence of carcinoma of the prostate gland (CaP) and high-grade prostatic intraepithelial neoplasia (HGPIN) was assessed in a Spanish population, representative of the Caucasian Mediterranean (CM) ethnic group. Data were compared with those described in populations from other geographical regions and in other ethnic groups.

METHODS

CaP and HGPIN were evaluated in a consecutive series of prostatic glands collected at the post-mortem examination of 162 male patients born and living in Spain, aged 20-80 years, and dying from trauma. The glands were sliced every 2-3 mm. All slices were paraffin embedded and sectioned to obtain 5 microm whole-mount sections. To compare the prevalence rate in our series and in other Caucasian populations with that from other geographical areas and other ethnic groups, we used data from the autopsy study performed at the Wayne State University.

RESULTS

Prevalence of CaP is 3.58, 8.82, 14.28, 23.80, 31.7, and 33.33% in the 3rd, 4th, 5th, 6th, 7th, and 8th decades, respectively. The rates of HGPIN were 7.14, 11.75, 35.71, 38.06, 45.40, and 48.15% at the 3rd, 4th, 5th, and 8th decades of life. Both CaP and HGPIN are located preferentially at the peripheral zone of the gland and in 21/27 cases (77.7%), an association between CaP and HGPIN was found. The prevalence of both lesions in CM males is significantly lower than in Caucasian American (CA) and Afro-American (AA) males in all the age groups evaluated.

CONCLUSIONS

Microscopic foci of CaP and HGPIN can be documented in CM males from the 3rd decade of life onwards. The lesions become more frequent and extensive as age increases. The prevalence of both lesions seems to be significantly lower in the CM population than in CA and AA males in all the age groups evaluated.

Postatrophic hyperplasia of the prostate in Japan: histologic and immunohistochemical features and p53 gene mutation analysis

BACKGROUND

Postatrophic hyperplasia (PAH) is one of the patterns of prostatic atrophy but has been regarded as a precursor of prostatic cancer (PCA) because of its possible increase in proliferative activity compared with simple atrophy and morphologic mimicry of PCA.

METHODS

Radical prostatectomy specimens obtained from 28 patients with PCA were analyzed by histologic and immunohistochemical methods by using 34 beta E12 and Ki-67 as primary antibodies. Tissue from PAH, PCA, high-grade prostatic intraepithelial neoplasia (HGPIN), a possible precursor of PCA, and benign hyperplasia were microdissected and p53 gene mutations were examined by the polymerase chain reaction-single strand conformation polymorphism method followed by direct sequencing.

RESULTS

Histologically, PAH consists of compactly arranged small acini with irregular atrophic-appearing contours, mimicking PCA. PAH lesions were detected in 7 (25%) of 28 cases with PCA: multifocal in 6 of 7 (85.7%) cases, maximum size of lesions ranged from 0.3 to 2.3 mm. Mild nuclear enlargement and small nucleoli were observed in all cases. Capsular or perineural invasion, crystalloids, and mitotic figures were not found in any case. Inflammatory changes and fibrosis near PAH were found in 100% and 71% of cases, respectively. PAH involved non-transition zone in all cases and occasionally involved transition zone. Forty-three percent of PAH lesions were in proximity (<2 mm) to PCA. None of the clinical and pathologic factors examined were correlated with the presence of PAH. Immunohistochemical analysis by using 34 beta E12 revealed intact basal cells. Proliferative activity defined by positive rate for labeling with MIB-1 antibody was intermediate between benign prostatic hyperplasia and HGPIN. The frequency of p53 mutations in PAH lesions was 5.3%, which was similar to that in HGPIN lesions (4.2%). Benign glands never showed mutations.

CONCLUSION

These findings suggested that PAH might be a precursor for PCA.

High grade prostatic intraepithelial neoplasia is a disease

High grade prostatic intraepithelial neoplasia (PIN) is now widely accepted as the main premalignant lesion that has the potential to progress to prostate adenocarcinoma. High grade PIN is a standard diagnosis that must be included as part of the reported pathologic evaluation of prostate biopsies. Premalignant lesions that affect other organs have been identified and are treated when diagnosed such that the premalignant lesions itself are a disease (eg, carcinoma in situ of the bladder, colon polyps, and cervical dysplasia). Urologists should recognize that high grade PIN is a dangerous lesion and that it should be aggressively managed either by saturation biopsies of the prostate following the diagnosis of high grade PIN, or the more common recommendation--repeated prostate biopsies every 3 to 6 months for 2 years, then annually. Treatment of these precancerous lesions would appear to be of clinical benefit notwithstanding the potential for cancer prevention. These clinical benefits would reduce morbidity, enhance the quality of life, delay surgery or radiation, and increase the interval for surveillance requiring invasive procedures.

Comparative studies of prostate cancer in Japan versus the United States. A review

This article reviews the available data on prostate cancer in Japan compared with that in the United States, with emphasis on epidemiologic, pathologic, and molecular aspects. Previous studies have demonstrated ethnic/racial differences in the incidence of prostate cancer between the two countries. Recent investigations indicate that different genetic alterations or polymorphisms are related to carcinogenesis in the prostate. Comparative geographic-pathologic autopsy studies suggest that different promoting factors including genetic, epigenetic, and environmental influences may be responsible for ethnic variations in the postinduction progression of prostate cancer.

Extent and zonal distribution of prostatic intraepithelial neoplasia in patients with prostatic carcinoma in Japan: analysis of whole-mounted prostatectomy specimens

BACKGROUND

Prostatic intraepithelial neoplasia (PIN), an intraluminar proliferation of epithelial cells in ducts and acini, is divided into high-grade (HGPIN) and low-grade (LGPIN), based on morphologies. HGPIN is considered to be a putative precursor of prostatic adenocarcinoma (PCA). Information on PIN has been limited in Japan, because PIN had not been regarded as a precursor lesion for PCA.

METHODS

In this study, extent and zonal distribution of PIN together with its relationship with PCA were examined in totally embedded radical prostatectomy specimens obtained from 70 patients with PCA. Fifty-three patients received androgen deprivation therapy (castrated) and remaining 17 did not (noncastrated).

RESULTS

Frequency of HGPIN in noncastrated cases (76%) was much higher than that in castrated cases (26%) (P < 0.001). LGPIN showed the same tendency, but the difference was smaller. Difference in mean number of HGPIN in noncastrated and castrated cases (12.0 and 6.4, respectively) was more marked than in LGPIN (6.4 and 5.1, respectively). Reduction rate of mean size in HGPIN (26%) by the androgen deprivation therapy was larger than in LGPIN. When evaluated in noncastrated cases, the coexistence of PCA and HGPIN was found in 76% of cases in the nontransition and 53% in the transition zone. Close association of PCA and PIN (</=2 mm distance between lesions) was more frequently found in HGPIN (55% of lesions) than in LGPIN (37%) (P < 0.05). Frequency of close association of HGPIN with PCA was 65% in the nontransition and 35% in transition zone.

CONCLUSIONS

The present study from Japan supports the etiological importance of HGPIN in the development of PCA. The effect of androgen deprivation therapy is much more marked in HGPIN than in LGPIN.