Significance of high-grade prostatic intraepithelial neoplasia in needle biopsy specimens

Management of an increasing prostate-specific antigen level after negative prostate biopsy

Patients who have a previously negative biopsy in the setting of clinical suspicion of prostate cancer still have a high risk of harboring significant undiagnosed disease. Various markers such as prostate-specific antigen (PSA) velocity, PSA density, PCA3, and newer markers may aid in repeat biopsy selection. Repeating the same biopsy procedure in such patients does not yield high cancer detection rates. More anteriorly directed transrectal or transperineal biopsies are indicated. Multiparametric magnetic resonance imaging can detect abnormal areas, and lesion-targeted biopsies can improve the cancer detection rate.

Phase III trial of selenium to prevent prostate cancer in men with high-grade prostatic intraepithelial neoplasia: SWOG S9917

The threat of prostate cancer and the significant and often negative impact of its treatment underscore the importance of prevention. High-grade prostatic intraepithelial neoplasia (HGPIN) has been identified as a potential premalignant lesion marking an increased risk of prostate cancer and substantial evidence suggests that men with HGPIN are in need of prostate cancer prevention. In vitro, in vivo, epidemiologic, and clinical trial evidence that selenium supplementation protects against prostate cancer motivated the study we report here: a double-blind, randomized, placebo-controlled trial of selenium 200 (μg/d) as selenomethionine in men with HGPIN. The primary endpoint was progression of HGPIN to prostate cancer over a 3-year period. This National Cancer Institute Intergroup trial was coordinated by the Southwest Oncology Group (SWOG). Of 619 enrolled patients, 423 randomized men with HGPIN (212 selenium and 211 placebo) were eligible (by central pathology review) and included in the primary analysis. Three-year cancer rates were 36.6% (placebo) versus 35.6% (selenium; P = 0.73, adjusted). The majority of patients who developed cancer on trial (70.8%, selenium and 75.5%, placebo) had a Gleason score of 6 or less than 6; there were no differences in Gleason scores between the two arms. Subset analyses included the finding of a nonsignificantly reduced prostate cancer risk (relative risk = 0.82; 95% CI: 0.40-1.69) in selenium versus placebo patients in the lowest quartile of baseline plasma selenium level (<106 ng/mL). Overall, and in all other subsets defined by baseline blood selenium levels, selenium supplementation had no effect on prostate cancer risk. The 36% prostate cancer rate in men with HGPIN indicates the association of this lesion with an elevated prostate cancer risk. Future study in this setting should focus on selenium-deficient populations and selenium pharmacogenetics.

Immunohistochemical examination of the mTORC1 pathway in high grade prostatic intraepithelial neoplasia (HGPIN) and prostatic adenocarcinomas (PCa): a tissue microarray study (TMA)

BACKGROUND

The mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase and a key regulator of protein synthesis and growth and is upregulated in many cancers. mTOR is activated by AKT phosphorylation (p-mTOR). p-mTOR associates with regulatory-associated protein of TOR (RAPTOR), forming the mTORC1 complex. mTORC1 promotes the activation of p70 ribosomal protein s6 kinase 1 (p70(S6K1)) and ribosomal protein s6 (RPS6). Upregulation of this pathway can lead to an aberrant increase in cell growth and metabolism characteristic of malignant transformation.

METHODS

This study presents the immunohistochemical (IHC) expression of the mTORC1 pathway in prostate neoplasia. The expression of p-mTOR and RAPTOR and p-p70(S6K1) and p-RPS6 were examined in HGPIN and PCa using tissue microarrays (TMA). Since each case in our TMAs was represented by three tissue cores, we quantified the IHC intratumoral heterogeneity of mTOR expression. This extensive analysis is the first detailed assessment documenting the IHC heterogeneity of mTOR expression in HGPIN and prostate cancer and represents the first IHC description of the mTORC1 pathway in HGPIN and PCa.

RESULTS

A Cochran-Armitage analysis demonstrated decreasing p-mTOR activity progressing from PIN through GL6 and GL7 to HG PCa. There was considerable intratumoral IHC heterogeneity within an individual patient. However, a statistically significant correlation was observed between p-mTOR, p-p70(S6K1), and p-RPS6 in each representative core.

CONCLUSION

mTOR inhibitors may be an effective treatment for HGPIN and PCa. The extent of mTOR expression in an individual patient would determine the effective use of mTOR inhibitors as a potential therapeutic strategy.

The proportion of cores with high-grade prostatic intraepithelial neoplasia on extended-pattern needle biopsy is significantly associated with prostate cancer on site-directed repeat biopsy

OBJECTIVE

To determine whether the predictive value of isolated high-grade prostatic intraepithelial neoplasia (HGPIN) for an unsampled prostate cancer on an extended biopsy is lower due to more thorough prostate sampling, and whether the proportion of cores with HGPIN is associated with prostate cancer, as isolated HGPIN on sextant prostate biopsy is associated with a 27-57% risk of prostate cancer on repeat biopsy.

PATIENTS AND METHODS

All extended prostate biopsies taken by one urologist over 6 years were reviewed for patients with isolated HGPIN on initial biopsy. Biopsies were evaluated for histological features and the proportion of cores with HGPIN. The clinical characteristics and pathological findings from subsequent biopsies were determined.

RESULTS

Of 577 men having extended biopsies, 48 had isolated HGPIN, followed by one to four site-directed repeat biopsies. Although only 10 (21%) had cancer on the first repeat biopsy, overall 15 (31%) had cancer. Those with cancer on repeat biopsy had a significantly higher proportion of cores with HGPIN, i.e. 29% vs 15%, cancer vs no cancer, respectively (P = 0.04).

CONCLUSIONS

Isolated HGPIN on extended biopsy conferred a 31% risk of unsampled prostate cancer. The proportion of cores with HGPIN on initial biopsy was significantly associated with the risk of cancer. The same was not true for age, race, prostate-specific antigen level, or the findings on digital rectal examination. The significant association between the proportion of cores with HGPIN and the risk of cancer suggests that patients with unifocal HGPIN on extended biopsy be managed expectantly, whereas those with multifocal HGPIN be re-biopsied.

Incidentally detected prostate cancer in cystoprostatectomies: pathological and morphometric comparison with clinically detected cancer in totally embedded specimens

There are limited data regarding the pathological features of incidentally detected prostate cancer. Examination of cystoprostatectomy specimens obtained during bladder cancer treatment affords a unique opportunity to examine incidentally detected prostate cancer and determine its relationship with clinically detected prostate cancer obtained during radical prostatectomy. We compared the pathological findings of incidentally detected prostate cancer in 132 consecutive cystoprostatectomy specimens from patients treated for bladder cancer with a consecutive series of 228 radical prostatectomy specimens from patients treated for prostate cancer. All specimens were totally embedded and whole-mounted. Karyometry was evaluated in select subsets of patients from the study groups. Incidentally detected cancer was found in 42% of cystoprostatectomy specimens, and the cancers were of lower Gleason score and lower pathological stage with fewer positive surgical margins than in clinically detected cancers in age-matched radical prostatectomies. High-grade prostatic intraepithelial neoplasia (PIN) was present in 82% of radical prostatectomy specimens, in 70% of cystoprostatectomies with incidentally detected prostate cancer, and in 54% of cystoprostatectomies without prostate cancer. Mean nuclear and nucleolar area was lower in incidentally detected cancer and PIN when compared with clinically detected cancer and PIN, respectively, similar to the results with proliferative indices. We conclude that incidentally detected cancer is less aggressive than clinically detected cancer.

Monofocal and plurifocal high-grade prostatic intraepithelial neoplasia on extended prostate biopsies: factors predicting cancer detection on extended repeat biopsy

OBJECTIVES

To evaluate factors predicting cancer detection by extended repeat prostate biopsies in patients with an initial, isolated, monofocal or plurifocal, high-grade prostatic intraepithelial neoplasia (HGPIN) diagnosis.

METHODS

From 1995 to 2002, after a first set of 10 to 12 systematic biopsy cores, 47 patients with an initial HGPIN diagnosis underwent repeat biopsy using the same technique (mean repeat biopsy cores 11.5) after a median follow-up of 11.4 months (range 3 to 24).

RESULTS

Cancer was detected at the second biopsy in 21 patients (44.6%). Cancer detection was significantly greater in patients with plurifocal HGPIN than in those with monofocal HGPIN (70% vs. 10%, respectively; P <0.005) and in patients who underwent repeat biopsy more than 6 months after the first biopsy set (65%) compared with patients who underwent repeat biopsy within 6 months (25%; P <0.01; mean follow-up 15.5 and 3.8 months, respectively). Multivariate analysis showed that prostate-specific antigen, prostate-specific antigen density, digital rectal examination, and transrectal ultrasound findings were not statistically significant predictors of prostate cancer, and HGPIN multifocality and interval between biopsies (more than a 6-month follow-up interval) were independent prognostic factors (odds ratio 4.65 and 2.65, respectively). After radical prostatectomy (14 patients), no statistically significant differences were found in the pathologic stage between patient groups stratified by repeat biopsy interval (within or after 6 months).

CONCLUSIONS

After a 10 to 12-core biopsy, patients with initial, isolated monofocal or plurifocal HGPIN diagnoses had an overall cancer detection rate of 45% on repeat extended biopsies. Plurifocal HGPIN on the first biopsy set was the strongest independent predictive factor in cancer detection. A 12 to 18-month interval before repeat biopsy could permit a significantly greater cancer detection rate, with no apparent likelihood of clinical cancer progression.

High-grade Prostatic Intraepithelial Neoplasia on Needle Biopsy

The importance of isolated high-grade prostatic intraepithelial neoplasia (HGPIN) on needle biopsy is its association with synchronous invasive carcinoma. The relevance of this relationship has been called into question in recent years. In our study, we examined whether the histologic subtype of HGPIN (ie, tufting, micropapillary, cribriform, flat) and/or the number of core biopsies involved by HGPIN was predictive of a subset of men who were at higher risk of having invasive carcinoma on follow-up biopsies. We examined 200 sets of needle biopsies with a diagnosis of isolated HGPIN. Patient age ranged from 46 to 90 years (mean 66.4 years). The breakdown of the histologic subtypes of HGPIN is as follows: tufting 59%, micropapillary 34.3%, cribriform 6.2%, and flat 0.5%. A total of 132 patients (66%) had follow-up biopsies. Prostatic adenocarcinoma was identified in 28.8% of patients with 89.5% of cancers identified on the first two follow-up biopsies. For men that had two or more cores with HGPIN on the initial biopsy, 35.9% eventually had cancer on follow-up whereas men with only single core involvement had cancer in 22% of cases. Men with tufting/flat HGPIN on the initial biopsy had cancer on follow-up in 31.9% of cases, whereas the micropapillary/cribriform subtype was associated with cancer in 22% of follow-up biopsies. The histologic findings on the first repeat biopsy can be quite informative as to the risk of synchronous invasive carcinoma. Of the men with HGPIN on the first repeat biopsy, 32% eventually had cancer on follow-up. Additionally, if multiple cores were involved by HGPIN on the first repeat biopsy, the risk of finding cancer was 50%, regardless of single or multiple core involvement on the initial biopsy. Men with a benign diagnosis on the first repeat biopsy had a 14% risk of having cancer on follow-up. These data indicate that the multiple core involvement by HGPIN, both on initial and first repeat biopsy, defines a subset of men that are at increased risk of harboring synchronous invasive carcinoma. The histologic subtype of PIN does not appear to be as informative.

Significance of high-grade prostatic intraepithelial neoplasia on prostate biopsy

The early diagnosis of prostate cancer has been facilitated by the development of serum prostate-specific antigen (PSA) testing and evolution in transrectal ultrasound-guided biopsy of the prostate. Over a decade has passed since the initial recommendations for systematic sextant sampling of the prostate to increase the accuracy of cancer detection. Subsequently, variations in the number and location of biopsies have been proposed to maximize prostate cancer detection and obtain more complete information regarding tumor grade, tumor volume, and local stage. Although current biopsy strategies provide a wide sampling of the prostate gland, biopsy histology may not be conclusive for either the presence or absence of adenocarcinoma. High-grade prostatic intraepithelial neoplasia (HGPIN) is found in a significant fraction of patients undergoing transrectal prostate biopsies. In this article, we discuss the significance of high-grade prostatic intraepithelial neoplasia and other abnormal histology findings and current evidence addressing the presence of cancer and need for additional prostate biopsies.

Is repeat prostate biopsy for high-grade prostatic intraepithelial neoplasia necessary after routine 12-core sampling?

OBJECTIVES

To determine whether repeat biopsy is necessary when the diagnosis of high-grade prostatic intraepithelial neoplasia (HGPIN) is made with a 12-core biopsy. Repeated biopsy has been recommended for individuals with HGPIN noted on sextant prostate biopsy because of the high likelihood of cancer detection. Recently, we have recommended the routine use of 12 cores, rather than 6, to improve cancer detection.

METHODS

The charts of all patients undergoing prostate biopsy during a 2-year period at the Manhattan Veterans Administration Medical Center were reviewed. Patients diagnosed with HGPIN on a 12-core biopsy were identified, and those undergoing a repeat 12-core biopsy within 1 year of the initial biopsy were evaluated to determine the rate of cancer detection.

RESULTS

A total of 619 men underwent biopsy during the study period. Of 103 men diagnosed with HGPIN, 43 underwent a repeat biopsy within 1 year at the discretion of the managing urologist. The mean age and median prostate-specific antigen level of those undergoing a repeat biopsy was 65.5 years and 5.37 ng/mL, respectively. At the time of the repeat biopsy, 1 patient was found to have cancer (2.3%), 20 had HGPIN (46.5%), 20 had benign pathologic findings (46.5%), and 1 patient (2.3%) had atypical small acinar proliferation.

CONCLUSIONS

A repeat biopsy after the diagnosis of HGPIN on 12-core prostate biopsy rarely results in cancer detection. In the absence of other factors increasing the suspicion of cancer, immediate repeat biopsy for HGPIN diagnosed on a 12-core biopsy is unnecessary.