RELATIONSHIP BETWEEN SYSTEMATIC BIOPSIES AND HISTOLOGICAL FEATURES OF 222 RADICAL PROSTATECTOMY SPECIMENS: LACK OF PREDICTION OF TUMOR SIGNIFICANCE FOR MEN WITH NONPALPABLE PROSTATE CANCER

Temporal changes in the pathologic assessment of prostate cancer

Thirty years have witnessed dramatic changes in the manner in which we diagnose and manage prostate cancer. With prostate-specific antigen screening, there was a shift towards smaller, clinically localized tumors. Tumors are often multifocal and display phenotypic and molecular heterogeneity. Pathologic evaluation of tissue obtained by needle biopsy remains the gold standard for the diagnosis and risk assessment of prostate cancer. Years of experience with grading, along with changes in the amount of biopsy tissue obtained and diagnostic tools available, have produced shifts in grading practices among genitourinary pathologists. Trends in Gleason grading and advances in pathological risk assessment are reviewed with particular emphasis on recent Gleason grading modifications of the International Society of Urologic Pathology. Efforts to maximize the amount of information from pathological specimens, whether it be morphometric, histochemical, or molecular, may improve predictive accuracy of prostate biopsies. New diagnostic techniques are needed to optimize management decisions.

Frequency and determinants of disagreement and error in gleason scores: a population-based study of prostate cancer

BACKGROUND

To examine factors that affect accuracy and reliability of prostate cancer grade we compared Gleason scores documented in pathology reports and those assigned by urologic pathologists in a population-based study.

METHODS

A stratified random sample of 318 prostate cancer cases was selected to ensure representation of whites and African-Americans and to include facilities of various types. The slides borrowed from reporting facilities were scanned and the resulting digital images were re-reviewed by two urologic pathologists. If the two urologic pathologists disagreed, a third urologic pathologist was asked to help arrive at a final "gold standard" result. The agreements between reviewers and between the pathology reports and the "gold standard" were examined by calculating kappa statistics. The determinants of discordance in Gleason scores were evaluated using multivariate models with results expressed as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

The kappa values (95% CI) reflecting agreement between the pathology reports and the "gold standard," were 0.61 (95% CI: 0.54, 0.68) for biopsies, and 0.37 (0.23, 0.51) for prostatectomies. Sixty three percent of discordant biopsies and 72% of discordant prostatectomies showed only minimal differences. Using freestanding laboratories as reference, the likelihood of discordance between pathology reports and expert-assigned biopsy Gleason scores was particularly elevated for small community hospitals (OR = 2.98; 95% CI: 1.73, 5.14).

CONCLUSIONS

The level of agreement between pathology reports and expert review depends on the type of diagnosing facility, but may also depend on the level of expertise and specialization of individual pathologists.

Knife or needles? A cohort analysis of outcomes after radical prostatectomy or brachytherapy for men with low- or intermediate-risk adenocarcinoma of the prostate

PURPOSE

The purpose of this study was to evaluate long-term outcomes for men with early stage prostate cancer treated with radical prostatectomy (RP) or brachytherapy (BT) at a single tertiary care center.

METHODS AND MATERIALS

We retrospectively analyzed data from 371 men with clinical T1a-T2c disease with prostate-specific antigen level <20 ng/mL and Gleason score (GS) 6-7 who were treated with RP (n=279) or BT (n=92) at MD Anderson Cancer Center in 2000-2001. Biochemical recurrence-free survival (BRFS) and prostate cancer-specific survival rates were compared by treatment modality.

RESULTS

The median followup time was 7.2 and 7.6 years for patients treated with RP and BT, respectively. Disease was upgraded from GS 6 to 7 after central review of the biopsy specimen for 36 men treated with RP (12.9%) and 15 men treated with BT (16.3%). After RP, GS was upgraded in 121 men (43.4%) between the centrally reviewed biopsy and the RP specimen. After RP, 5-year BRFS rates were 96.1% and 90.6% for low- and intermediate-risk disease, respectively (p=0.003). After BT, 5-year BRFS rates were 92.5% and 95.8% for low- and intermediate-risk disease, respectively (p=0.017). After RP or BT, 5-year BRFS rates were not significantly different with GS upgraded. Five-year prostate cancer-specific survival rates for patients with upgraded GS were 100% for both RP and BT.

CONCLUSIONS

Excellent disease control outcomes can be achieved after either RP or BT as monotherapy for men with early stage prostate cancer. Upgrading of GS from 6 to 7, either (3+4) or (4+3), did not predict for worse outcomes.

Performance characteristics of prostate-specific antigen in patients undergoing radical prostatectomy

OBJECTIVE

To assess the performance characteristics of prostate-specific antigen (PSA) for predicting the volume of total or high-grade cancer in men undergoing radical prostatectomy. It is known that the performance characteristics of PSA are improved for predicting the presence of high-grade prostate cancer.

METHODS

We identified 1459 patients from the Stanford Radical Prostatectomy Database with clinical Stage T1c (n = 783) and T2 (n = 676) disease who underwent surgery from 1988 to 2003 with detailed morphometric mapping. We generated receiver operating characteristic curves for PSA levels according to the total and high-grade (Gleason score 4 or 5) cancer volume and compared the areas under the curve (AUC) for the various total and high-grade cancer volumes.

RESULTS

For patients with Stage T1c disease, the AUC for the PSA ROC curve increased in a stepwise fashion as both the total cancer volume and the high-grade cancer volume increased. Significant differences between the AUCs for low and high volumes of total and high-grade disease were observed. For T2 disease, the AUCs for predicting high-grade cancer volume were generally greater than the corresponding AUCs for T1c disease, although no incremental increase was observed.

CONCLUSION

In patients with Stage T1c disease, in whom the PSA level was the driving force for biopsy, the PSA performance improved in a stepwise fashion with greater total and high-grade cancer volumes as evidenced by improved ROC. Previous studies have shown that PSA performs better for detecting the presence of high-grade disease. We have shown that PSA performs better in predicting greater volumes of high-grade disease in radical prostatectomy specimens.

Automatic computer-aided detection of prostate cancer based on multiparametric magnetic resonance image analysis

In this paper, a fully automatic computer-aided detection (CAD) method is proposed for the detection of prostate cancer. The CAD method consists of multiple sequential steps in order to detect locations that are suspicious for prostate cancer. In the initial stage, a voxel classification is performed using a Hessian-based blob detection algorithm at multiple scales on an apparent diffusion coefficient map. Next, a parametric multi-object segmentation method is applied and the resulting segmentation is used as a mask to restrict the candidate detection to the prostate. The remaining candidates are characterized by performing histogram analysis on multiparametric MR images. The resulting feature set is summarized into a malignancy likelihood by a supervised classifier in a two-stage classification approach. The detection performance for prostate cancer was tested on a screening population of 200 consecutive patients and evaluated using the free response operating characteristic methodology. The results show that the CAD method obtained sensitivities of 0.41, 0.65 and 0.74 at false positive (FP) levels of 1, 3 and 5 per patient, respectively. In conclusion, this study showed that it is feasible to automatically detect prostate cancer at a FP rate lower than systematic biopsy. The CAD method may assist the radiologist to detect prostate cancer locations and could potentially guide biopsy towards the most aggressive part of the tumour.

Prostate-Specific Antigen Density as a Powerful Predictor of Extracapsular Extension and Positive Surgical Margin in Radical Prostatectomy Patients with Prostate-Specific Antigen Levels of Less than 10 ng/ml

Purpose

To assess the ability of preoperative variables to predict extracapsular extension (ECE) and positive surgical margin (PSM) in radical prostatectomy patients with prostate-specific antigen (PSA) levels of less than 10 ng/ml.

Materials and Methods

From January 2008 to December 2009, 121 patients with prostate cancer with PSA levels lower than 10 ng/ml who underwent radical prostatectomy were enrolled in the study. The differences in clinical factors (age, PSA, PSA density [PSAD], digital rectal examination [DRE] positivity, positive magnetic resonance imaging [MRI], Gleason sum, positive core number, and positive biopsy core percentage) with ECE and the presence of positive margins were determined and their independent predictive significances were analyzed.

Results

The ECE-positive patients had higher PSA, PSAD, and MRI-positive percentages, and PSM patients had higher PSA, PSAD, MRI-positive percentages, Gleason sum, and positive biopsy core percentages for prostate cancer. In the multivariate analysis, PSAD and MRI positivity were the best independent predictors for ECE, and PSA and PSAD were the best independent predictors of PSM. By receiver operating characteristic curve analysis, PSAD had better discriminative area under the curve value than did PSA for ECE (0.765 vs 0.661) and PSM (0.780 vs 0.624). The best predictive PSAD value was 0.29 ng/ml/cc for ECE and 0.27 ng/ml/cc for PSM.

Conclusions

PSAD has relevance to ECE (plus MRI findings) and PSM (plus PSA). PSAD might be a powerful predictor of ECE and PSM preoperatively in patients undergoing a radical prostatectomy with PSA levels of less than 10 ng/ml.

High-grade prostatic adenocarcinoma present in a single biopsy core is associated with increased extraprostatic extension, seminal vesicle invasion, and positive surgical margins at prostatectomy

OBJECTIVE

To evaluate the pathologic outcome of prostate-specific antigen-screened patients with high-grade (Gleason score ≥ 8) prostate cancer limited to 1 biopsy core, without clinical evidence of disease.

METHODS

Ninety-two patients with only 1 biopsy core with cancer and treated by radical prostatectomy were divided into 4 groups according to the biopsy Gleason score: 3 + 3 = 6 (23 cases), 3 + 4 = 7 (25 cases), 4 + 3 = 7 (20 cases), and ≥ 8 (24 cases).

RESULTS

Cases with Gleason score ≥ 8 showed a significantly higher proportion of extraprostatic extension (50%), positive surgical margins (21%), and seminal vesicle invasion (12%) when compared with the other groups. Patients with Gleason score ≥ 8 in the biopsy had a 25-fold increased in the odds ratio for extraprostatic extension in the prostatectomy. The incidence of extraprostatic extension was higher in those with prostatic cancer involving ≥ 50% of one core (88%) compared with cases involving <50% (32%).

CONCLUSION

In patients with prostate cancer limited to 1 biopsy core, the presence of Gleason score ≥ 8 significantly increased the incidence of extraprostatic extension, positive surgical margins, and seminal vesicle invasion. The odds ratio was substantially higher in patients with ≥ 50% of Gleason ≥ 8 in the biopsy core. These data might be taken into account for proper clinical management of this set of patients.

Prostate cancer: multiparametric MR imaging for detection, localization, and staging

This review presents the current state of the art regarding multiparametric magnetic resonance (MR) imaging of prostate cancer. Technical requirements and clinical indications for the use of multiparametric MR imaging in detection, localization, characterization, staging, biopsy guidance, and active surveillance of prostate cancer are discussed. Although reported accuracies of the separate and combined multiparametric MR imaging techniques vary for diverse clinical prostate cancer indications, multiparametric MR imaging of the prostate has shown promising results and may be of additional value in prostate cancer localization and local staging. Consensus on which technical approaches (field strengths, sequences, use of an endorectal coil) and combination of multiparametric MR imaging techniques should be used for specific clinical indications remains a challenge. Because guidelines are currently lacking, suggestions for a general minimal protocol for multiparametric MR imaging of the prostate based on the literature and the authors' experience are presented. Computer programs that allow evaluation of the various components of a multiparametric MR imaging examination in one view should be developed. In this way, an integrated interpretation of anatomic and functional MR imaging techniques in a multiparametric MR imaging examination is possible. Education and experience of specialist radiologists are essential for correct interpretation of multiparametric prostate MR imaging findings. Supportive techniques, such as computer-aided diagnosis are needed to obtain a fast, cost-effective, easy, and more reproducible prostate cancer diagnosis out of more and more complex multiparametric MR imaging data.

The relationship between Prostate CAncer gene 3 (PCA3) and prostate cancer significance

OBJECTIVE

To evaluate the relationship between Prostate CAncer gene 3 (PCA3) and prostate cancer significance.

PATIENTS AND METHODS

Clinical data from two multi-centre European open-label, prospective studies evaluating the clinical utility of the PCA3 assay in guiding initial and repeat biopsy decisions were analysed. First-catch urine was collected after digital rectal examination (three strokes per lobe) and the PCA3 score was determined using the PROGENSA(®) PCA3 assay. Transrectal ultrasound-guided biopsy (≥8 cores) and radical prostatectomy (RP) specimens were analysed by the local pathologist. The relationship between biopsy and RP outcomes with the PCA3 score was assessed.

RESULTS

Of the 1009 men enrolled, 348 (34%) had a positive biopsy. The median and mean PCA3 scores were statistically significantly lower in men with biopsy Gleason score <7 vs ≥7, with clinical stage T1c vs T2a-T2c, T3a cancers, with ≤33% vs >33% positive biopsy cores and with 'biopsy indolent' vs 'biopsy significant' prostate cancer (indolent prostate cancer defined by biopsy Epstein criteria). In all, 175 men with a positive biopsy had a RP: median and mean PCA3 scores were statistically significantly lower in men with pathological Gleason score <7 vs ≥7, and with pathological stage T2a-T2c vs T3a-T3b cancers.

CONCLUSIONS

The PCA3 score may combined with traditional tools aid in identifying men with clinically insignificant prostate cancer, as shown by biopsy and RP pathological features including biopsy Epstein criteria, who could be candidates for active surveillance. Treatment selection should be based on a combination of clinical and pathological variables. If one wants to use a threshold point to guide treatment decisions in clinical practice, a PCA3 score threshold of 20 may have the highest utility for selecting men with clinically insignificant prostate cancer in whom active surveillance may be appropriate; a PCA3 score threshold of 50 may be used to identify men at high risk of harbouring significant prostate cancer who are candidates for RP. Although the association between the PCA3 score and prostate cancer aggressiveness needs further evaluation, the inclusion of the PCA3 score into patient management strategies may provide clinicians with another tool to more accurately determine the course of treatment.

The contemporary concept of significant versus insignificant prostate cancer

CONTEXT

The notion of insignificant prostate cancer (Ins-PCa) has progressively emerged in the past two decades. The clinical relevance of such a definition was based on the fact that low-grade, small-volume, and organ-confined prostate cancer (PCa) may be indolent and unlikely to progress to biologic significance in the absence of treatment.

OBJECTIVE

To review the definition of Ins-PCa, its incidence, and the clinical impact of Ins-PCa on the contemporary management of PCa.

EVIDENCE ACQUISITION

A review of the literature was performed using the Medline, Scopus, and Web of Science databases with no restriction on language up to September 2010. The literature search used the following terms: insignificant, indolent, minute, microfocal, minimal, low volume, low risk, and prostate cancer.

EVIDENCE SYNTHESIS

The most commonly used criteria to define Ins-PCa are based on the pathologic assessment of the radical prostatectomy specimen: (1) Gleason score ≤ 6 without Gleason pattern 4 or 5, (2) organ-confined disease, and (3) tumour volume<0.5 cm(3). Several preoperative criteria and prognostication tools for predicting Ins-PCa have been suggested. Nomograms are best placed to estimate the risk of progression on an individualised basis, but a substantial proportion of men with a high probability of harbouring Ins-PCa are at risk for pathologic understaging and/or undergrading. Thus, there is an ongoing need for identifying novel and more accurate predictors of Ins-PCa to improve the distinction between insignificant versus significant disease and thus to promote the adequate management of PCa patients at low risk for progression.

CONCLUSIONS

The exciting challenge of obtaining the pretreatment diagnostic tools that can really distinguish insignificant from significant PCa should be one of the main objectives of urologists in the following years to decrease the risk of overtreatment of Ins-PCa.

Assessment of circulating tumor cells (CTCs) in prostate cancer patients with low-volume tumors

The objective of this study was to assess the incidence of circulating tumor cells (CTCs) in prostate cancer patients with low-volume tumors (less than 0.5 cc) after radical prostatectomy (RP). Blood samples were collected from 64 RP patients to assess the incidence of CTCs following RP. The specimens were processed by whole-mount section. Clinicopathological data (e.g. patient age, race, specimen weight, tumor volume, grade, stage and surgical margin status) and follow-up PSA data were compared to CTC status. Of the 64 RP patients, nine had 'low-volume prostate cancer'. Seven of these patients had detectable levels of CTCs. In two of the seven patients with detectable CTCs, PSA elevation was also observed. Isolation and detection of circulating epithelial cells is possible in low-volume prostate cancer patients. In the setting of low-volume prostate cancer, CTCs may be associated with the presence of detectable PSA levels. However, the detection of CTCs did not predict PSA failure.

Nomogram to predict insignificant prostate cancer at radical prostatectomy in Korean men: a multi-center study

PURPOSE

Due to the availability of serum prostate specific antigen (PSA) testing, the detection rate of insignificant prostate cancer (IPC) is increasing. To ensure better treatment decisions, we developed a nomogram to predict the probability of IPC.

MATERIALS AND METHODS

The study population consisted of 1,471 patients who were treated at multiple institutions by radical prostatectomy without neoadjuvant therapy from 1995 to 2008. We obtained nonrandom samples of n = 1,031 for nomogram development, leaving n = 440 for nomogram validation. IPC was defined as pathologic organ-confined disease and a tumor volume of 0.5 cc or less without Gleason grade 4 or 5. Multivariate logistic regression model (MLRM) coefficients were used to construct a nomogram to predict IPC from five variables, including serum prostate specific antigen, clinical stage, biopsy Gleason score, positive cores ratio and maximum % of tumor in any core. The performance characteristics were internally validated from 200 bootstrap resamples to reduce overfit bias. External validation was also performed in another cohort.

RESULTS

Overall, 67 (6.5%) patients had a so-called "insignificant" tumor in nomogram development cohort. PSA, clinical stage, biopsy Gleason score, positive core ratio and maximum % of biopsy tumor represented significant predictors of the presence of IPC. The resulting nomogram had excellent discrimination accuracy, with a bootstrapped concordance index of 0.827.

CONCLUSION

Our current nomogram provides sufficiently accurate information in clinical practice that may be useful to patients and clinicians when various treatment options for screen-detected prostate cancer are considered.

Determining prostate cancer-specific death through quantification of stromogenic carcinoma area in prostatectomy specimens

We previously reported that reactive stroma grading in prostate cancer (PCa) is predictive of biochemical recurrence in prostatectomies and biopsies. In this study, we tested whether quantifying the percentage of reactive stromal grade 3 (RSG 3; stromogenic carcinoma pattern) in the entire tumor is predictive of PCa-specific death. Whole-mount prostatectomies operated by a single surgeon obtained between 1983 and 1998 were reviewed. Reactive stroma was evaluated as described previously, and areas of RSG 3 in the entire tumor were registered as percentages of total tumor. Statistical analysis was performed using Spearman, Kaplan-Meier, and Cox analyses. In all, 872 cases were evaluable. Quantification of RSG 3 percentage was an independent predictor of biochemical recurrence, analyzed as a continuous or grouped variable. Patients with higher RSG 3 percentages (larger tumor areas with RSG 3) had a significantly decreased biochemical recurrence-free survival than those with a lower RSG 3 percentage, even within the Gleason score 7 subset of patients. A nomogram introduced this new variable to the model. Furthermore, quantification of RSG 3 percentage was significantly predictive of PCa-specific death. Quantification of the RSG 3 (stromogenic carcinoma) area in PCa provides additional novel information on prognosis. These data substantiate the concept that the tumor microenvironment holds significant predictive information, as well as biological significance.

[Mass screening for prostate cancer at Ikeda City in Osaka Prefecture--results of screening with PSA alone between 2003 and 2007]

PURPOSE

Since 2003, screening with prostate specific antigen (PSA) has been conducted to detect prostate cancer. We investigated the results between 2003 and 2007.

PATIENTS AND METHODS

Screening with PSA alone was performed for males aged over 50 years who desired prostate cancer screening. We used a PSA cutoff value of 4.00 ng per milliliter.

RESULTS

In 2003, there were 18,161 males aged over 50 years in Ikeda City. 3,738, 3,905, 4,129, 4,410, and 4,515 of the males underwent PSA screening in 2003, 2004, 2005, 2006, and 2007. The rate of elevated PSA levels was 7.9%-9.8% (median 9.1%). 161, 81, 70, 75 and 60 of the males visited us for secondary screening, and prostate biopsy was performed in 130 (80.7%), 57 (70.4%), 45 (64.3%), 38 (50.7%), and 42 (70.0%). Prostate cancer was detected in 91, 33, 29, 20 and 25 males, respectively. These values corresponded to 2.43%, 0.85%, 0.70%, 0.45% and 0.55% of the males who underwent primary screening. The incidence of prostate cancer was 0.96% during the 5 years. Clinical stage was B in 137 (69.2%), C in 52 (26.3%), D in 7 (3.5%), and unknown in 2. Surgery was performed in 87 (43.9%), endocrine therapy in 61 (30.8%), irradiation in 37 (18.7%), and follow up without treatment in 7 (3.5%). Treatment for 6 (3.0%) is unknown because they desired treatment at another hospital.

CONCLUSIONS

198 males were diagnosed with prostate cancer between 2003 and 2007. The clinical stage B was present in 137 (69.2%), and the early treatment was achieved. This may lead to a future decrease in the mortality rate.

Detection rates of nonpalpable prostate cancer in Korean men with prostate-specific antigen levels between 2.5 and 4.0 ng/mL

OBJECTIVE

To evaluate the detection rate and pathology of cancer in Korean men with low levels of prostate-specific antigen (PSA), 2.5-4.0 ng/mL.

METHODS

We examined 1097 patients with PSA level of 2.5-10.0 ng/mL, who underwent transrectal ultrasonography-guided prostate needle biopsies between January 2008 and March 2009. Of the 1097 biopsy patients, 815 met our criteria of benign findings by digital rectal examination and the absence of cancerous lesions by TRUS. Clinical characteristics and detection rates of prostate cancer, as well as the pathology of specimens obtained by needle biopsies and prostatectomies, were evaluated in these patients.

RESULTS

Of the 815 patients, 349 had group 1 (PSA level, 2.5-4.0 ng/mL) and 466 had group 2 (PSA level, 4.0-10.0 ng/mL). The percentage of patients diagnosed with prostate cancer was not statistically different between the 2 groups (21.8% in group 1, and 20.2% in group 2). In group 1, 70.7% of patients had a pathologic Gleason score of 7 or higher and 91.4% had organ-confined tumors (pT2). The pathologic characteristics, including Gleason score, pathologic stage, and percentage of insignificant cancer were similar in prostatectomy specimens between group 1 and group 2.

CONCLUSIONS

Detection rates of nonpalpable prostate cancer in Korean men were 21.8% in group 1 and 20.2% in group 2 without statistically significant difference. Pathologic characteristics of prostatectomy specimens also were similar between group 1 and group 2. These results suggest that a lower PSA level might be considered as an indication for prostate biopsy.

Radical prostatectomy findings in patients predicted to have low-volume/low-grade prostate cancer diagnosed by extended-core biopsies: an analysis of volume and zonal distribution of tumour foci

OBJECTIVE

To measure total tumour volume (TTV) and dominant TV (DTV) in radical prostatectomy (RP) specimens from patients predicted to have low-volume, low-grade (LV/LG) prostate cancer, as this entity can be predicted from biopsy findings and prostate-specific antigen (PSA) level, but tumour under-sampling remains a challenge in active surveillance programmes.

PATIENTS AND METHODS

This was a retrospective study from an academic centre, of men with prostate cancer treated from 2000 to 2007, with a PSA level of <10 ng/mL and one core of cancer from an extended scheme showing either Gleason score (GS) 3 + 3 of <3.0 mm or 3 + 4 of <2.0 mm. All men had RP, and the TTV, DTV, tumour location, pathological GS and stage were measured.

RESULTS

Of 3055 RPs, 66 (2.1%) met the inclusion criteria. The core with cancer was from a sextant and alternative site in 26 (39%) and 40 (61%) patients, respectively. A pathological GS 3 + 3 or 3 + 4 was assigned to 94%, while 6% were GS > or = 4 + 3; all 66 tumours were organ-confined. The median (range) TTV and DTV were 0.15 (0.0008-5.06) and 0.14 (0.0008-5.04) mL, respectively. The median number of tumour foci was 3 (1-7), being unifocal in 17/66 (26%) and multifocal in 49/66 (74%). The transition zone was involved in 29% of unifocal and 71% of multifocal tumours. Of all 66 patients, the TTV was <0.5 mL in 47 (71%), and of 59 patients with biopsy GS 3 + 3, 33 (56%) had a TTV of <0.5 mL and pathological GS 3 + 3. Of 19 patients with a TTV of > or =0.5 mL, the median TTV was 1.06 (0.51-5.05) mL, with tumour foci of transition zone origin in 16 (84%). The study was limited by its retrospective design and small sample size.

CONCLUSIONS

Using conservative selection criteria for predicting LV/LG cancer, RP specimens showed organ-confined disease in all cases, upgrading to GS > or = 4 + 3 in 6%, and TTV <0.5 mL in 71% of cases. The transition zone is a common location of under-sampled disease.

The value of EZH2, p27(kip1), BMI-1 and MIB-1 on biopsy specimens with low-risk prostate cancer in selecting men with significant prostate cancer at prostatectomy

OBJECTIVE

To assess the additional prognostic value of the molecular markers EZH2, MIB-1, p27(kip1) and BMI-1 on needle biopsies from men with low-risk prostate cancer, as this disease in needle biopsies shows a heterogeneous clinical outcome, and while it is known that the expression of these tissue markers is predictive of the clinical outcome after radical prostatectomy (RP) their value in prostate biopsies is largely unknown.

PATIENTS AND METHODS

The study included men participating in a screening study, diagnosed with low-risk prostate cancer and subsequently treated with RP. Immunohistochemical staining for EZH2, MIB-1, p27(kip1) and BMI-1 on the needle biopsies were (semi)quantitatively scored and expression levels were related to significant disease at RP. Clinical low-risk prostate cancer was defined as a prostate-specific antigen (PSA) level of < or =10 ng/mL, clinical T-stage < or =2, biopsy Gleason score < or =6, a PSA density of <0.20 ng/mL/g and two or fewer positive cores. Significant PC at RP was defined as presence of any of extracapsular extension, Gleason pattern 4/5, or tumour volume > or =0.5 mL.

RESULTS

In all, 86 biopsy specimens were included; there was high EZH2 expression (>1.0%) in 42% and a low p27(kip) expression (<90%) in 63%. Significant disease was present in 44 (51%) RP specimens. A high EZH2 (odds ratio 3.19, P = 0.043) and a low p27(kip1) (4.69, P = 0.036) were independent predictors for significant prostate cancer at RP.

CONCLUSIONS

The determination of EZH2 and p27(kip1) on diagnostic needle biopsies supports the selection of men with indolent prostate cancer at RP. Especially p27(kip1) could improve the pretreatment risk assessment of patients with low-risk prostate cancer.

Is tumor vascularity in prostate core biopsies a predictor of PSA recurrence after radical prostatectomy?

The purposes of this study were to evaluate if tumour vascularity by Chalkley counting (TVC) in prostate core biopsies can be a predictor of PSA recurrence after radical prostatectomy in prostate cancer and to estimate the concordance between the TVC in core biopsies and the subsequently examined prostatectomy specimen. All patients, with Gleason score < or =7 in core biopsy, clinical stage T1 or T2 who had a radical prostatectomy during 1990-1997 at Sahlgrenska University Hospital, were selected as a primary group. Patients with neoadjuvant hormonal therapy were excluded. The patients were divided into two groups, one with PSA recurrence and one group without PSA recurrence. 25 patients had PSA recurrence during the follow up period and 25 patients from non-recurrence group were randomly selected. TVC was assessed from the prostate tissue by immunostaining against CD34. TVC was statistically significant predictor of PSA relapse. The PSA-free survival rate was only 17% in patients within the highest TVC quartile compared to 67% in patients within the lowest TVC quartile.

Diffusion and perfusion MR imaging of the prostate

Conventional anatomic MR imaging has evolved to a superior modality in the evaluation of prostate carcinoma and is now a widely established technique in the detection and staging of this disease, aiding in clinical decision making on treatment and therapy evaluation. Recent improvements in functional MR techniques, such as diffusion-weighted MR imaging and dynamic contrast-enhanced MR imaging, have greatly increased the impact of MR imaging in prostate cancer. The combination of T2-weighted imaging, diffusion-weighted MR imaging, and dynamic contrast-enhanced MR imaging may overcome the limitations of conventional T2-weighted MR imaging of the prostate and may be able accurately to detect, localize, stage, and grade prostate carcinoma and guide biopsies.

Diagnostic accuracy of extended biopsies for the staging of microfocal prostate cancers in autopsy specimen

Clinically insignificant prostate cancers may be predicted when biopsies show a microfocal cancer (MiFC). However, at least one-third of MiFC are underestimated by biopsies. The aim of this study was to evaluate the staging accuracy of different biopsy regimen showing a MiFC. We performed 18 biopsy cores on 164 autopsy prostates. Six cores were taken from the mid-peripheral zone (MPZ), 6 from the lateral PZ (LPZ) and 6 from the central zone (CZ). We tested seven different biopsy regimens by distinguishing the MPZ, LPZ or CZ biopsies either separately or associated with each other. Of the cancers detected by biopsies, we selected those showing a MiFC and compared our findings with whole mount analysis. The positive predictive value of a MiFC referred to how often, when needle biopsies showed a MiFC, there was a clinically insignificant cancer on whole mount prostate analysis. We found that the positive predictive value of a MiFC on 6 or 12 biopsy cores was similar irrespective of biopsy location (P approximately 1). On MPZ, MPZ plus LPZ and all 18 biopsies, it was 40, 70 and 87%, respectively (P<0.1). Tumor volume of cancers showing a MiFC on MPZ biopsies was significantly higher than those showing a MiFC on MPZ plus LPZ, or all 18 biopsies (P<0.05). These results show that performing additional cores in case of MiFC on sextant biopsies may help differentiating significant from insignificant cancers.

[Insignificant prostate cancer. Analysis our series]

The objective of this study is to analyse the specimen of radical prostatectomy of patients who had, prior to the surgery insignificant prostate cancer biopsies. The end point is demonstrate the possibility of an active surveillance as a therapeutic option for prostate cancer in selected is the possibility of an active surveillance as therapeutic for the prostate cancer, in selected individuals if we are able to find diagnostic algorisms to predict the real insignificant tumours. The selected group of patients for the study has a PSA less or equal 10, one positive core of prostatic transrectal ultrasound biopsy with a Gleason score less than 7. This group of patients is considerate as having a potential insignificant tumour. We will consider prostatectomy's specimens and the Gleason sore is less than 7 and the tumoral volume is les or equal to 5%. Of 394 patients with prostate cancer and homogeneous criterias for our study, we have selected 53 patients according to the criteria of insignificant tumour in the biopsy. Our results showed that only 22 of 53 (41.5%) patients were identified as having an insignificant prostate cancer in the RP specimens. Moreover 92.2% of this tumours were organ-confined. In conclusion we are able to say that tumours of low-risk and low tumoral volume in the biopsy, do not correlate always to insignificant tumours in PR specimens, but we have observed that the majority are organ-confined tumours. Finally, the diagnostic's algorisms dies not to predict tumours that may safely treated with active monitoring.

[Active surveillance for prostate cancer]

Active surveillance is a valuable treatment option in patients with newly diagnosed low-risk prostate cancer. Studies considering a watchful waiting approach showed favourable cancer-specific survival rates in such patients and it is assumed that patients benefit from a definitive therapy if life expectancy exceeds 10-15 years. Therefore active surveillance is especially valuable in older men and in patients with an elevated comorbidity profile. Precise identification of histologically and clinically insignificant prostate cancers is still not possible today. Active surveillance includes regular PSA measurements combined with follow-up biopsies; however, no standardized protocol exists so far. Histological progression in the follow-up biopsy and PSA elevation are the most important criteria for initiating definitive therapy. Today only a minority of low-risk patients join an active surveillance protocol and a substantial proportion of these men leave such a protocol early without evidence of progression. The psychological burden of living with an untreated cancer seems to be responsible for this. Active surveillance has the potential to lead to undertreatment as there is some evidence that prolonged treatment delay might adversely affect outcome of definitive therapy.

Do patients with low volume prostate cancer have prostate specific antigen recurrence following radical prostatectomy?

Aims:

The objective of this study was to determine the incidence of prostate specific antigen (PSA) relapse in patients with low volume prostate cancer following radical prostatectomy.

Methods:

Between 1993 and 2001, 50 of 717 patients had total tumour volumes of less than 0.5 cm3 following radical prostatectomy. Biochemical recurrence was defined as two consecutive values of serum PSA levels of 0.2 ng/ml or greater.

Results:

Median follow-up of the 50 patients was 58 months. In five of the 50 patients (10%), PSA recurrence was observed. All of these five cases had Gleason score of 3+3 (well and/or moderately differentiated), organ confined and surgical margin negative tumours. In three of the five cases, capsular incision resulted in benign glands extending into the surgical margin.

Conclusions:

Five of 50 cases had PSA failure. In three of the five patients, benign glands located in the margin could explain the “PSA recurrence”. However, in the other two patients, none of the pathological parameters correlated with measurable PSA levels. The explanation for their PSA failure is unclear.

Pathologic characteristics of cancers detected in The Prostate Cancer Prevention Trial: implications for prostate cancer detection and chemoprevention

The Prostate Cancer Prevention Trial (PCPT) showed a risk of prostate cancer at prostate-specific antigen (PSA) <4.0 ng/mL and that prostate cancer risk is reduced by finasteride. A major concern about early detection by PSA and prevention by finasteride is that they may involve biologically inconsequential tumors. We reviewed the pathologic characteristics of prostate biopsies from men in the placebo and finasteride groups of the PCPT. We examined tumor pathology characteristics stratified by level of PSA for men in the placebo group who underwent radical prostatectomy. Seventy-five percent of all cancers and 62% of Gleason score <or=6 cancers in the PCPT met the biopsy criteria for clinically significant tumors. Surrogate measures for tumor volume (number of cores positive, percent cores positive, linear extent, and bilaterality) and risk of perineural invasion were lower in men who received finasteride. The PSA-associated risks of insignificant cancer were 51.7% (PSA, 0-1.0 ng/mL), 33.7% (1.1-2.5 ng/mL), 17.8% (2.6-4.0 ng/mL), and 11.7% (4.1-10 ng/mL). Conversely, the risks of high-grade (Gleason score >or=7) tumors for the same PSA strata were 15.6%, 37.9%, 49.1%, and 52.4%, respectively. These data highlight the dilemma of PSA when used for screening: Lower cutoff levels increase detection of insignificant disease, but cure is more likely, whereas higher cutoff levels make detection of significant cancer more likely, but cure is less likely. Therefore, the effectiveness of finasteride in preventing prostate cancer, including Gleason score <or=6 cancer, with meaningful rates of significant disease in the PCPT suggests that cutoff values for PSA screening should be individualized and that men undergoing screening should be informed of the opportunity to reduce their risk of disease with finasteride.

Assessment of pathological prostate cancer characteristics in men with favorable biopsy features on predominantly sextant biopsy

BACKGROUND

The rate of insignificant prostate cancer (IPCa) is increasing.

OBJECTIVES

To examine three end points in patients with a single, positive core and no high-grade prostate cancer (PCa) at biopsy, namely (1) rate of clinical IPCa at radical prostatectomy (RP), defined as organ-confined PCa with a Gleason score of 6 or lower and tumor volume<0.5 cc; (2) rate of pathologically unfavorable PCa at RP (Gleason 7-10 or non-organ-confined disease); and (3) ability to predict either insignificant or unfavorable PCa at RP.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of 209 men with one positive biopsy core showing Gleason 6 or lower.

MEASUREMENTS

: Detailed clinical and RP data were used in multivariable logistic regression models. Their bias-corrected accuracy estimates were quantified using the area under the curve (AUC) method.

RESULTS AND LIMITATIONS

At RP, IPCa was present in 28 patients (13.4%) and pathologically unfavorable PCa, defined as Gleason 7 or higher or non-organ-confined PCa, was reported in 70 (33.5%) of 209 men; when Gleason 8 or higher or non-organ-confined PCa was considered, the proportion fell to 11%. Our multivariable models predicting different categories of pathologically unfavorable PCa at RP had an accuracy rate between 56% and 68% for predicting IPCa at RP versus 65.1% to 66.1% and 61.7% for the IPCa nomograms of Kattan et al and Nakanishi et al, respectively. Our data are not applicable to screening because they originate from a referral population.

CONCLUSIONS

Despite highly favorable biopsy features, between 11% and 33% of men had unfavorable PCa at RP and only a minority (13.4%) had pathologically confirmed IPCa. Neither clinically insignificant nor pathologically unfavorable features could be predicted with sufficient accuracy for clinical decision making.

Validation of pretreatment nomograms for predicting indolent prostate cancer: efficacy in contemporary urological practice

PURPOSE

Many patients diagnosed with low grade and early stage prostate cancer have indolent disease and may not benefit from immediate therapy. In patients referred for biopsy following community screening we validated the Kattan and Steyerberg nomograms for predicting indolent disease in a contemporary urological practice.

MATERIALS AND METHODS

A total of 296 patients who underwent prostate biopsy and radical prostatectomy at a single institution were identified for nomogram validation. All patients had clinically localized, stage T1c or T2a and biopsy Gleason score 6 prostate cancer. Clinical and biopsy pathological information was compared to surgery pathology results for nomogram validation with indolent disease defined as surgical Gleason score 6 or less, tumor volume less than 0.5 cc and organ confined disease. Nomogram performance was assessed by the ROC curve.

RESULTS

Of the patients 27.4% had pathologically indolent disease at prostatectomy. Based on pretreatment variables the Kattan and Steyerberg nomograms were able to predict indolent disease with similar discrimination levels (AUC 0.777 and 0.772, respectively).

CONCLUSIONS

Two previously described nomograms performed equally well for predicting indolent disease. These data further establish the role of validated nomograms for clinical decision making for managing screening detected prostate cancer.

Trends in Gleason score: concordance between biopsy and prostatectomy over 15 years

OBJECTIVES

To assess the changes in the concordance rate of prostate biopsy and radical prostatectomy (RP) Gleason score (GS) over 15 years.

METHODS

We reviewed 1670 consecutive patients who underwent RP between 1992 and 2006. We excluded patients who underwent neoadjuvant hormone therapy or salvage RP, or who had incomplete data. Patients who had RP during 1992 through 1996, 1997 through 2001, and 2002 through 2006 were assigned to groups 1, 2, and 3, respectively. All clinical and pathological data were collected retrospectively. We defined overgrading as a biopsy GS higher than the RP Gleason score. Undergrading was a biopsy GS less than the RP Gleason score. The GS concordance between biopsy and RP was evaluated by kappa coefficient.

RESULTS

A total of 1363 patients satisfied the inclusion criteria. Biopsy and RP Gleason score categories correlated exactly in 937 (69%) men. Gleason undergrading occurred in 361 (26%) men and overgrading in 65 (5%). The exact correlation of GS between biopsy and RP was 58%, 66%, and 75% in groups 1, 2, and 3, respectively. The most common discordant finding was undergrading of the biopsy specimen. The number of cases with exact correlation was highest in GS 7 (78%). Undergrading was more in GS 6 or less (35%) and overgrading was more in the GS 8 through 10 (35%) category.

CONCLUSIONS

This large, single institutional study confirms increasing concordance of Gleason scores in prostate needle biopsies and surgical specimens. This is reassuring for patients assessing various treatment options for prostate cancer.

Percentages of positive cores, cancer length and Gleason grade 4/5 cancer in systematic sextant biopsy are all predictive of adverse pathology and biochemical failure after radical prostatectomy

AIM

We investigated whether the quantitative parameters of systematic sextant biopsies were predictive of either adverse pathological findings or disease recurrence after radical prostatectomy (RP).

METHODS

We retrospectively evaluated a total of 117 men with untreated prostate cancer whose needle biopsies were matched with RP specimens. The pretreatment parameters of the serum prostate-specific antigen (PSA), the PSA density, the percentage of positive biopsy cores, the percentage of cancer length and the percentage of Gleason grade 4/5 cancer in the biopsy were determined and compared with the pathological features of prostate cancer in RP specimens. These pretreatment parameters and pathological factors in the RP specimens, including the cancer volume, the percentage of Gleason grade 4/5 cancer, the positive surgical margin and the seminal vesicle invasion were evaluated for their ability to predict the disease recurrence.

RESULTS

The percentages of positive biopsy cores, the Gleason grade 4/5 cancer in the biopsy and the cancer length in the biopsy had a weak correlation with the cancer volume in RP specimens (r = 0.373, 0.345, 0.408, respectively). All quantitative biopsy parameters were strongly predictive of the non-organ-confined status, the positive surgical margin and the seminal vesicle invasion in the logistic regression analysis. The percentage of positive biopsy cores and the percentage of Gleason grade 4/5 cancer in the biopsy predicted biochemical failure after RP.

CONCLUSION

These results indicate that quantitative biopsy parameters are independent predictors of the adverse pathology of prostate cancers and disease recurrence after RP.

Prediction of pathological stages before prostatectomy in prostate cancer patients: analysis of 12 systematic prostate needle biopsy specimens

OBJECTIVE

To identify the most reliable predictor of the pathological stage among multiple parameters obtained by performing systematic biopsies and to assess the predictive value of any identified parameters in combination with the prostate specific antigen and the Gleason scores.

METHODS

We examined 5 biopsy parameters from 12 systematic needle biopsy results in 104 consecutive prostate cancer patients who underwent prostatectomy: the number of cores positive for cancer, percentage of positive biopsy cores, total linear cancer length (absolute sum of tumor length at each core), percentage cancer length (total cancer length divided by total length of cores obtained x100), and maximum cancer core length. The predictive values of these parameters were assessed using multivariate logistic analysis and receiver operating characteristic analysis. We evaluated whether the most reliable biopsy parameter in combination with traditional variables show better predictability of the pathological stage than traditional variables alone by receiver operating characteristic analysis.

RESULTS

Of 104 patients, 85 (82.9%) had organ confined cancer and 19 (17.1%) showed extraprostatic extension. Of the five parameters examined, maximum cancer length was found to best predict pathological staging. Although insignificant, adding results of maximum cancer length to prostate specific antigen and Gleason scores improved predictability. Of 41 patients with a maximum cancer length of <0.9 cm, PSA of <16 ng/mL, and Gleason score of <7, none showed extraprostatic extension.

CONCLUSIONS

The maximum cancer length was found to be the most reliable predictor of disease staging. The findings of a maximum cancer length of <0.9 cm, PSA of <16 ng/mL, and a Gleason score of <7 can suggest an organ-confined disease.

Preoperative prediction of multifocal prostate cancer and application of focal therapy: review 2007

Prostate cancer is a leading malignancy among men. Early prostate cancer is most commonly treated with radical surgery and radiotherapy. In the era of prostate-specific antigen and newly emerging highly specific screening tests, a greater number of men are given a diagnosis earlier in life, and disease is more often confined. Less-invasive treatments, such as focal therapy, are becoming increasingly popular, yielding shorter hospital stays, faster recovery, and fewer complications. Potential drawbacks to focal therapy include the risk of incomplete treatment, which may result from missed cancer foci and inadequate ablation to target tissues. Furthermore, this approach is not universally applicable to all patients--for example, those who have periurethral and extraprostatic extension of the tumor may not benefit from focal treatment. This article reviews the importance of multifocal prostate cancer and the application of focal treatment.

Saturation prostate needle biopsy and prostate cancer detection at initial and repeat evaluation

OBJECTIVES

To evaluate the incidence of prostate cancer (PCa) in patients who underwent a saturation prostate biopsy (SPBx) as primary biopsy or in case of rebiopsy.

METHODS

We assessed 189 patients (median age 60.3 years) submitted to a transrectal ultrasound-guided SPBx (range, 24 to 37 cores; median, 29). In 98 men the SPBx was performed as the primary procedure, in 75 as the second, and in 16 as the third biopsy set. Indications for biopsy were: abnormal DRE; total prostate specific antigen (PSA) (tPSA) greater than 10 ng/mL; tPSA equal to 4 to 10, 2.6 to 3.9, less than or equal to 2.5 ng/mL; and percent free PSA (%-fPSA) 25% or less, 20% or less, and 15% or less, respectively. The PCa detection using an SPBx as initial biopsy was compared retrospectively with that found in 256 and 116 patients who underwent 12- and 18-core biopsy, respectively, according to the same protocol. The results obtained in 75 patients submitted to an SPBx as the second biopsy set were compared retrospectively with those found in 73 men who underwent an 18-core re-biopsy.

RESULTS

The PCa detection rate with SPBx as primary biopsy was 46.9%, greater than the 12-core biopsy (39.8%; P = 0.3) but lower than the 18-core biopsy (49%; P = 0.6). In the case of second and third biopsy, the incidence of PCa when using an SPBx compared with 18-core biopsy was 22% versus 10.9% (P = 0.003) and 6.2% versus 0%, respectively. The incidence of neoplastic microfoci was 34.7% at first and 45.5% at second biopsy set. In all patients who underwent a radical prostatectomy with a bioptic diagnosis of neoplastic microfocus, the pTNM revealed a clinically significant cancer (tumor volume greater than 0.5 mL or Gleason score of 6 or higher).

CONCLUSIONS

As primary biopsy, SPBx does not increase the PCa detection rate compared with an 18-core scheme; in the case of rebiopsy, the SPBx is a recommended method as the PCa detection rate is doubled compared with 12- or 18-core biopsy sets.

Active surveillance for favorable-risk prostate cancer: who, how and why?

Active surveillance for favorable-risk prostate cancer has become increasingly common in populations in which screening for prostate cancer is widespread, owing to evidence that in many patients screening results in the detection of disease that is not clinically significant (i.e. untreated, it would not pose a threat to health). The approach is supported by data demonstrating that patients who have clinically insignificant disease can be identified with reasonable accuracy, and that patients who are initially classified as low risk but reclassified over time as higher risk and are treated radically are still cured in most cases. It is important to identify patients who have a low probability of disease progression during their lifetime according to clinical and pathologic features of the disease, patient age and comorbidity. Close monitoring of patients over time and availability of reasonable criteria for intervention, which will both identify more-aggressive disease in a timely fashion and not result in excessive treatment, are crucial. It is also important to communicate appropriately with the patient, to reduce the psychological burden of living with untreated cancer. The results of active surveillance, the criteria for patient selection and the appropriate thresholds for intervention are reviewed in this article.

Preoperative determination of prostate cancer tumor volume: analysis through biopsy fragments

OBJECTIVE

Preoperative determination of prostate cancer (PCa) tumor volume (TV) is still a big challenge. We have assessed variables obtained in prostatic biopsy aiming at determining which is the best method to predict the TV in radical prostatectomy (RP) specimens.

MATERIALS AND METHODS

Biopsy findings of 162 men with PCa submitted to radical prostatectomy were revised. Preoperative characteristics, such as PSA, the percentage of positive fragments (PPF), the total percentage of cancer in the biopsy (TPC), the maximum percentage of cancer in a fragment (MPC), the presence of perineural invasion (PNI) and the Gleason score were correlated with postoperative surgical findings through an univariate analysis of a linear regression model.

RESULTS

The TV correlated significantly to the PPF, TPC, MPC, PSA and to the presence of PNI (p < 0.001). However, the Pearson correlation analysis test showed an R2 of only 24%, 12%, 17% and 9% for the PPF, TPC, MPC, and PSA respectively. The combination of the PPF with the PSA and the PNI analysis showed to be a better model to predict the TV (R2 of 32.3%). The TV could be determined through the formula: Volume = 1.108 + 0.203 x PSA + 0.066 x PPF + 2.193 x PNI.

CONCLUSIONS

The PPF seems to be better than the TPC and the MPC to predict the TV in the surgical specimen. Due to the weak correlation between those variables and the TV, the PSA and the presence of PNI should be used together.

hK2 and free PSA, a prognostic combination in predicting minimal prostate cancer in screen-detected men within the PSA range 4-10 ng/ml

OBJECTIVES

The purpose of screening for prostate cancer is to decrease the disease-specific mortality. However not every screen-detected prostate cancer is a threat to the patient's life. The risk of overdetection and subsequent overtreatment in prostate cancer has been recognised. The purpose of this investigation was to evaluate the role of tumour markers total PSA, free PSA, and hK2, and their combinations in predicting minimal prostate cancer.

METHODS

Within the European Randomized Study of Screening for Prostate Cancer (ERSPC), section Rotterdam, The Netherlands, prebiopsy serum samples were analysed for 100 selected men who underwent a radical prostatectomy for their screen-detected prostate cancer. All had a PSA value between 4 and 10 ng/ml prior to diagnosis. Minimal prostate cancer is defined as organ confined, Gleason score </=6 (no Gleason grade 4 or 5), and tumour volume <0.5 ml.

RESULTS

Sera and tumour volumes from 91 men were available for analysis. Minimal prostate cancer was diagnosed in 16.5% of the selected cases. Mean tumour volume was 1.2 ml (range: 0.04-13.5); hK2, the algorithms hK2/fPSA, and hK2/%fPSA have significant correlations with tumour volume. Both algorithms also yielded the best test results in predicting minimal disease with an area under the receiver operator characteristics curve of 82%.

CONCLUSIONS

hK2 and percent free PSA have added prognostic value for the detection of minimal prostate cancer in screen-detected cases within PSA range 4-10 ng/ml. These biomarkers can possibly be used to select less invasive treatment options like active surveillance and to prevent overtreatment.

Validation of a prediction model for low volume/low grade cancer: application in selecting patients for active surveillance

PURPOSE

We previously demonstrated that assessment of the number of positive cores, tumor length in a core, Gleason score and prostate volume significantly enhanced the accuracy of a prediction model for low volume/low grade cancer in men who had undergone extended biopsy. To determine the validity of the model, we applied it to an independent population of men with prostate cancer.

MATERIALS AND METHODS

The study group included 170 men who had undergone radical prostatectomy without neoadjuvant therapy. In all cases, prostate cancer was diagnosed on only 1 positive core of a 10-core extended biopsy. We assessed the accuracy of the model, which consists of tumor length less than 2 mm, Gleason score 3+4 or less and prostate gland volume greater than 50 cc in predicting the occurrence of low volume/low grade cancer (defined as tumor volume less than 0.5 cc, no Gleason grade 4 or 5 disease, and organ confined disease).

RESULTS

Of the patients 101 (59.4%) had low volume/low grade cancer. Our model using all 3 previously mentioned variables had the highest performance, demonstrating a positive predictive value of 70.4% (88 of 125), a negative predictive value of 71.1% (32 of 45) and a diagnostic accuracy of 70.6% (120 of 170). This model performed better than a model based on tumor length only (positive predictive value, negative predictive value and diagnostic accuracy 68.1%, 57.9% and 64.7%, respectively) or a model based on tumor length and Gleason score (positive predictive value, negative predictive value and diagnostic accuracy 70.0%, 60.0% and 66.5%, respectively).

CONCLUSIONS

This study validates that our model with a combination of tumor length, Gleason score and prostate volume is predictive for low volume/low grade cancer in an independent population of men who demonstrated only 1 positive core in an extended biopsy. This model can be used as a tool for selecting men for active surveillance.