Systematic Prostate Biopsies Are More And More Often Becoming Saturation Biopsies

Comparison of 8, 10, 12, 16, 20 cores prostate biopsies in the determination of prostate cancer and the importance of prostate volume

INTRODUCTION

In this study, we evaluate the relationship between increasing core numbers and cancer detection rate.

METHODS

We included 1120 patients with prostate-specific antigen levels ≤20 ng/mL and/or suspicious digital rectal examination findings in this study. All patients had a first-time prostate biopsy and 8, 10, 12, 16, and 20 core biopsies were taken and examined in different groups during the study. Multiple logistic regression analysis was made to reach the factor affecting the cancer detection rate between the patients with and without cancer. A p < 0.05 was considered statistically significant.

RESULTS

Out of 1120 patients, 221 (19.7%) had prostate cancer. Again of the total 1120 patients, 8 core biopsies were taken from 229 (20.4%); 10 core biopsies from 473 (42.2%); 12 core biopsies from 100 (8.9%); 16 core biopsies from 140 (12.5%); and 20 core biopsies from 178 (15.9%) patients. The increase in the core number increased the cancer detection rate by 1.06 times (p = 0.008).

CONCLUSIONS

As long as prostate volume increases, increasing the core number elevates the cancer detection rate. Thus, the rate of missed cancer will be reduced and the rates of unnecessary repetitive biopsy decreases.

Extended biopsy based criteria incorporating cumulative cancer length for predicting clinically insignificant prostate cancer

What's known on the subject? and What does the study add? The criteria used for selecting patients with prostate cancer for active surveillance (AS) are still not satisfactory due to the difficulty in predicting the significance of the prostate cancer. Urologists could predict insignificant prostate cancer by incorporating cumulative cancer length and biopsy Gleason score, derived from extended biopsy. The present study has added new criteria for predicting insignificant prostate cancer, which would lead to a better selection of candidates for AS.

OBJECTIVE

• To develop extended biopsy based criteria for predicting insignificant cancer (IC) using extended biopsy findings.

PATIENTS AND METHODS

• From 2000 to 2009, 1575 patients with prostate cancer were primarily treated by radical prostatectomy in two referral hospitals. • Of these, the study cohort comprised 499 patients with extended biopsy confirmed, clinically organ-confined (cT1-2N0M0) prostate cancer with PSA levels of <20 ng/mL. • Cancer information obtained through extended biopsy included cumulative cancer length (CCL) divided by the number of biopsy cores (CCL/core).

RESULTS

• Pathological examination revealed 39 ICs (7.8%). All these ICs fell in a category of prostate cancer with clinical stage ≤ T2a and 2005 International Society of Urological Pathology Consensus Conference (ISUP) modified biopsy Gleason score ≤ 7. • Accordingly, we analysed predictors of IC in a subset cohort of 370 patients in this category. A multivariate logistic regression analysis revealed that 2005 ISUP modified biopsy Gleason score and CCL/core were independently significant predictors of IC. • We determined a threshold value of CCL/core of 0.20 mm for predicting IC using receiver operating characteristic analysis. • Based on these findings, we developed simple extended biopsy based criteria for predicting IC as follows: (i) PSA level of <20 ng/mL; (ii) Clinical stage ≤ T2a; (iii) 2005 ISUP modified biopsy Gleason score ≤ 6; (iv) CCL/core of <0.20 mm. • The specificity of the criteria was 91%, which was significantly higher than the value from a subset of criteria without item iv (P < 0.001).

CONCLUSION

• We have developed extended biopsy based criteria for predicting IC incorporating the 2005 ISUP modified biopsy Gleason score and CCL/core.

Optimizing performance and interpretation of prostate biopsy: a critical analysis of the literature

CONTEXT

The number and location of biopsy cores and the interpretation of prostate biopsy in different clinical settings remain the subjects of continuing debate.

OBJECTIVE

Our aim was to review the current evidence regarding the performance and interpretation of initial, repeat, and saturation prostatic biopsy.

EVIDENCE ACQUISITION

A comprehensive Medline search was performed using the Medical Subject Heading search terms prostate biopsy, prostate cancer, detection, transrectal ultrasound (TRUS), nomogram, and diagnosis. Results were restricted to the English language, with preference given to those published within the last 3 yr.

EVIDENCE SYNTHESIS

At initial biopsy, a minimum of 10 but not >18 systematic cores are recommended, with 14-18 cores in glands ≥ 50 cm³. Biopsies should be directed laterally, and transition zone (TZ) cores are not recommended in the initial biopsy setting. Further biopsy sets, either as an extended repeat or as a saturation biopsy (≥ 20 cores) including the TZ, are warranted in young and fit men with a persistent suspicion of prostate cancer. An immediate repeat biopsy is not indicated for prior high-grade prostatic intraepithelial neoplasia diagnosis given an adequate extended initial biopsy. Conversely, biopsies with atypical glands that are suspicious but not diagnostic of cancer should be repeated within 3-6 mo. Overall recommendations for further biopsy sets (a third set or more) cannot be made. Transrectal ultrasound-guided systematic biopsies represent the standard-of-care method of prostate sampling. However, transperineal biopsies are an up-to-standard alternative.

CONCLUSIONS

The optimal prostatic biopsy regimen should be based on the individualized clinical setting of the patient and should follow the minimum standard requirements reported in this paper.

A novel gene signature for molecular diagnosis of human prostate cancer by RT-qPCR

BACKGROUND

Prostate cancer (CaP) is one of the most relevant causes of cancer death in Western Countries. Although detection of CaP at early curable stage is highly desirable, actual screening methods present limitations and new molecular approaches are needed. Gene expression analysis increases our knowledge about the biology of CaP and may render novel molecular tools, but the identification of accurate biomarkers for reliable molecular diagnosis is a real challenge. We describe here the diagnostic power of a novel 8-genes signature: ornithine decarboxylase (ODC), ornithine decarboxylase antizyme (OAZ), adenosylmethionine decarboxylase (AdoMetDC), spermidine/spermine N(1)-acetyltransferase (SSAT), histone H3 (H3), growth arrest specific gene (GAS1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and Clusterin (CLU) in tumour detection/classification of human CaP.

METHODOLOGY/PRINCIPAL FINDINGS

The 8-gene signature was detected by retrotranscription real-time quantitative PCR (RT-qPCR) in frozen prostate surgical specimens obtained from 41 patients diagnosed with CaP and recommended to undergo radical prostatectomy (RP). No therapy was given to patients at any time before RP. The bio-bank used for the study consisted of 66 specimens: 44 were benign-CaP paired from the same patient. Thirty-five were classified as benign and 31 as CaP after final pathological examination. Only molecular data were used for classification of specimens. The Nearest Neighbour (NN) classifier was used in order to discriminate CaP from benign tissue. Validation of final results was obtained with 10-fold cross-validation procedure. CaP versus benign specimens were discriminated with (80+/-5)% accuracy, (81+/-6)% sensitivity and (78+/-7)% specificity. The method also correctly classified 71% of patients with Gleason score<7 versus > or =7, an important predictor of final outcome.

CONCLUSIONS/SIGNIFICANCE

The method showed high sensitivity in a collection of specimens in which a significant portion of the total (13/31, equal to 42%) was considered CaP on the basis of having less than 15% of cancer cells. This result supports the notion of the "cancer field effect", in which transformed cells extend beyond morphologically evident tumour. The molecular diagnosis method here described is objective and less subjected to human error. Although further confirmations are needed, this method poses the potential to enhance conventional diagnosis.

Direct comparison between transrectal and transperineal extended prostate biopsy for the detection of cancer

AIM

To establish whether extended transrectal (TR) and extended transperineal (TP) biopsies are equivalent in detecting prostate cancer.

METHODS

Due to an elevated prostate-specific antigen (PSA) greater than 2.5 ng/mL or abnormal digital rectal examination findings, 783 men underwent a transrectal ultrasound-guided three-dimensional 26-core biopsy, a combination of TR 12-core and TP 14-core biopsies. Using recursive partitioning, the best combination of sampling sites that gave the highest cancer detection rate at a given number of biopsy cores was selected either with a TR or a TP approach. The cancer detection rate and characteristics of detected cancers were compared between the TP 14-core and the TR 12-core biopsies and between selected subset biopsy schemes.

RESULTS

Prostate cancer was detected in 283 of the 783 men (36%). There was no statistical difference in cancer detection rate or in the characteristics of detected cancers between TP 14-core and TR 12-core biopsies. As far as the best combination of sampling sites was selected, there was no statistical difference in cancer detection rates or in the characteristics of detected cancers between the TP and the TR subset biopsy schemes up to 12 cores. TP and TR biopsies performed equally, regardless of a history of negative biopsy, a digital rectal examination finding, the PSA level or the prostate volume.

CONCLUSIONS

We demonstrated for the first time that extended TP biopsy is as effective as its TR counterpart in detecting cancer and the characteristics of detected cancers, as far as sampling sites are selected to maximize the cancer detection rate.