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

Comparison of cancers detected at only a sextant or alternative location

OBJECTIVES

To evaluate the effect of the tumour-positive biopsy site at extended biopsy on tumour volume and potential biological significance of prostate cancer.

PATIENTS AND METHODS

We retrospectively evaluated radical prostatectomy specimens from 247 consecutive men diagnosed with prostate cancer by extended biopsy. Men who had both a positive sextant and alternative site were excluded, resulting in 132 evaluable men. We assessed age, pretreatment prostate-specific antigen (PSA) level, prostate volume, pathological stage, Gleason score, total tumour volume, and location (sextant or alternative site) of the positive biopsy. Patients were grouped by location of the positive biopsy, i.e. sextant site only or alternative site only, including anterior horn, midline region and transition zone.

RESULTS

A biopsy from a sextant-only or an alternative site only was positive in 42% (56/132) and 58% (76/132) of men, respectively. There was no significant difference in PSA level, number of positive cores, pathological stage, Gleason score, total tumour volume or the incidence of low-volume/low-grade cancer (volume <0.5 mL and a Gleason score of </=6) between the groups. In men with one positive core, there was no significant difference in total tumour volume (median 0.20 vs 0.36 mL, respectively) or in the incidence of low-volume/low-grade cancer (42% vs 40%, respectively) between the groups.

CONCLUSIONS

Total tumour volume and the incidence of low-volume/low-grade cancer detected at an alternative site only were comparable to those of cancers detected at a sextant site only. Alternative site biopsy did not increase the incidence of low-volume/low-grade cancers detected.

The utility of magnetic resonance imaging and spectroscopy for predicting insignificant prostate cancer: an initial analysis

OBJECTIVE

To design new models that combine clinical variables and biopsy data with magnetic resonance imaging (MRI) and MR spectroscopic imaging (MRSI) data, and assess their value in predicting the probability of insignificant prostate cancer.

PATIENTS AND METHODS

In all, 220 patients (cT stage T1c or T2a, prostate-specific antigen level <20 ng/mL, biopsy Gleason score 6) had MRI/MRSI before surgery and met the inclusion criteria for the study. The probability of insignificant cancer was recorded retrospectively and separately for MRI and combined MRI/MRSI on a 0-3 scale (0, definitely insignificant; - 3, definitely significant). Insignificant cancer was defined from surgical pathology as organ-confined cancer of </= 0.5 cm(3) with no poorly differentiated elements. The accuracy of predicting insignificant prostate cancer was assessed using areas under receiver operating characteristic curves (AUCs), for previously reported clinical models and for newly generated MR models combining clinical variables, and biopsy data with MRI data (MRI model) and MRI/MRSI data (MRI/MRSI model).

RESULTS

At pathology, 41% of patients had insignificant cancer; both MRI (AUC 0.803) and MRI/MRSI (AUC 0.854) models incorporating clinical, biopsy and MR data performed significantly better than the basic (AUC 0.574) and more comprehensive medium (AUC 0.726) clinical models. The P values for the differences between the models were: base vs medium model, <0.001; base vs MRI model, <0.001; base vs MRI/MRSI model, <0.001; medium vs MRI model, <0.018; medium vs MRI/MRSI model, <0.001.

CONCLUSIONS

The new MRI and MRI/MRSI models performed better than the clinical models for predicting the probability of insignificant prostate cancer. After appropriate validation, the new MRI and MRI/MRSI models might help in counselling patients who are considering choosing deferred therapy.

Should Men with Serum Prostate-Specific Antigen ≤4 ng/ml and Normal Digital Rectal Examination Undergo a Prostate Biopsy?

The clinical significance of a prostate cancer (PCa) cannot be determined solely by tumor volume (< or =0.5 cm(3)), as small tumors of higher Gleason grade and tumors occurring in younger men may become clinically significant even though the initial volume at diagnosis is small. A certain number of these minimal cancers are likely to remain clinically insignificant; however, it is unpredictable how many can progress beyond the curable stage by the time there is a rise in serum prostate-specific antigen (PSA) values. Compared to clinically detected PCa, PCa detected exclusively by PSA screening (clinical stage T1c) are less likely to be advanced but no more likely to be insignificant in terms of volume, pathologic stage, and Gleason pattern. Only 10-15% of PSA-detected cancers have the features of PCa found at autopsy or in cystoprostatectomy specimens. Actually, 25-30% of PCa are detected with PSA values between 2.5 and 4 ng/ml, and most of these cancers are clinically significant. Evidence from both retrospective and longitudinal studies has shown that the risk of a PCa is dependent on the patient's age and the initial serum PSA. This allows an individualized approach to PCa screening programs, and PSA cutoff values for biopsy indication may be lowered in selected patients.

The combination of millimetres of cancer and Gleason index in core biopsy is a predictor of extraprostatic disease

AIMS

The Gleason index (GI) is related to several pathological endpoints in radical prostatectomy (RP) specimens, including the risk of extraprostatic disease (ED). The amount of tumour (TM) in core biopsy (CB) specimens also correlates with staging. The aim was to determine whether the sum of the relative statistical weights of GI and TM in CBs strengthens the prediction of ED in RPs.

METHODS AND RESULTS

A series of 290 RPs and their previous respective CBs were reviewed. TM and the GI were blindly evaluated in CBs and statistically correlated with ED in RPs. A total of 60 (20.6%) RPs showed ED. The logistic regression model indicated that all cases with > 22 mm of cancer in CB showed ED in RP. All cases with a GI > 7 and > 12 mm of cancer in CB displayed ED. Finally, Pearson's chi2 revealed that 80% of cases with a GI > 7 and > or = 5 mm of cancer in CB showed ED in RP.

CONCLUSIONS

The combined evaluation of GI and TM in CB is a useful method to strengthen the prediction of ED, is based on two simple morphological criteria and may be used as an additional tool to choose the best treatment modality.

Prostate gland volume is a strong predictor of biopsy results in men 70 years or older with prostate-specific antigen levels of 2.0-10.0 ng/mL

PURPOSE

The incidence of prostate cancer, benign prostatic enlargement and serum level of prostate-specific antigen (PSA) increase with patient age. Intermediate elevation of PSA in elderly populations is apt to be considered insignificant. We evaluated the impact of PSA and prostate volume on the presence of non-palpable prostate cancer in elderly men with an intermediate level of PSA.

MATERIALS AND METHODS

Clinical records of 154 men 70 years or older, with non-cancerous digital rectal examination findings and with serum PSA levels of 2.0-10.0 ng/mL, who underwent initial 6- to 10-core transrectal prostate biopsy, were reviewed for prostate volume, number of biopsy cores, PSA and associated parameters. Stepwise logistic regression and receiver operating characteristic (ROC) models were used to determine the impacts of the parameters on the biopsy results.

RESULTS

Overall cancer detection rate was 40/154 or 26.0%. Prostate-specific antigen showed no significant association with the presence of prostate cancer (P = 0.59, Mann-Whitney U-test), while prostate volume did (P < 0.0001). On stepwise logistic regression analysis, prostate volume (P = 0.024, 95% CI 1.008-1.116) and biopsy core density (P = 0.017, 95% CI 4.76-7.12 x 10(6)) were independently associated with a cancer diagnosis, whereas PSA density was not an independent factor for a positive biopsy result. The area under the ROC curve for prostate volume was significantly superior to that of PSA (0.802 vs. 0.529; P = 0.012).

CONCLUSIONS

In men 70 years or older with gray zone PSA, prostate cancer patients are equally distributed over any PSA range. Although PSA has less impact on cancer presence than mere prostate volume, prostate cancer would be detected in a substantial proportion of older patients with PSA levels of 2.0-10.0 ng/mL.

Prostate needle biopsy: 12 vs. 18 cores -- is it necessary?

INTRODUCTION

The aim of this study is to compare the histological results of a prostate needle biopsy scheme of 12 and 18 cores used in 372 consecutive patients submitted to an early stage diagnosis programme for prostate cancer (PCa).

MATERIALS AND METHODS

From February 2002 to July 2003 a transperineal TRUS-guided prostate needle biopsy was performed in 372 patients aged 40-73. Indications for biopsy were: suspected DRE, total PSA (PSAt) >10 ng/ml; PSAt equal to 4-10, 2.6-3.9, < or =2.5 ng/ml and PSA F/T <25%, <20% and <15%, respectively. In 256 patients, we performed 12 cores and in 116 cases 18 cores.

RESULTS

159 (42.7%) patients were diagnosed with PCa, 138 (37%) with BPH, 58 (15.7%) with chronic prostatitis, 15 (4%) with a HGPIN, 2 (0.6%) with ASAP. In patients that underwent 12 and 18 cores the incidence of PCa was 39.8 and 49%; the incidence of PCa in patients with PSA < or =10 and >10 ng/ml submitted to 12 and 18 cores was 35 vs. 47% and 57.8 vs. 52%, respectively. The preponderance of clinical stage T1c was 50% (12 cores) vs. 72% (18 cores). The median bioptic Gleason score in both groups resulted 6.6 (12 cores) and 6 (18 cores). In 110 (12 bioptic cores) and in 30 (18 bioptic cores) patients that underwent a RRP, the pTNM proved a significant clinical neoplasm (Gleason score > or =6 and/or tumoral volume >0.5 cm(3)) in the first group in all cases, while in the second group in 28/30 (94%) cases.

CONCLUSIONS

Extended schemes of prostate needle biopsy of 18 or more cores increases the PCa diagnosis in early stage and should be adopted for young patients with a PSA <10 ng/ml, negative DRE and in case of rebiopsies.

Prediction of potentially insignificant prostate cancer in men undergoing radical prostatectomy for clinically organ-confined disease

BACKGROUND

The objectives of the present study were to characterize, according to tumor significance, the clinicopathological features of patients with prostate cancer who underwent radical prostatectomy, and to determine useful parameters for predicting insignificant disease before surgery.

METHODS

In this series, we included 195 patients who underwent radical prostatectomy for clinically organ-confined prostate cancer at our institution between January 1999 and November 2003. Several clinicopathological factors were analyzed, focusing on whether the largest tumor volume in radical prostatectomy specimens was >/=0.5 cm(3) or <0.5 cm(3), which is the criterion defined to distinguish insignificant cancer from significant cancer.

RESULTS

Potentially insignificant cancer was detected in 28 of 195 patients (14.4%). There were significant differences between patients with insignificant disease and those with significant disease in serum prostate specific antigen (PSA) as well as all biopsy parameters, with the exception of biopsy Gleason score. Furthermore, final pathological examination demonstrated that these two patient groups showed significant differences in Gleason score and the incidence of extraprostatic disease extension. Pearson's correlation analysis showed that tumor volume in the prostatectomy specimens was significantly associated with serum PSA and all biopsy parameters; however, each of the correlations was comparatively weak. There was no single parameter that could viewed as a useful predictor of tumor significance. The best model for predicting insignificant tumor was the combined use of biopsy Gleason score <7 and percent of positive biopsy core (PPBC) <15%; however, the further addition of serum PSA <10 ng/mL to these two parameters failed to enhance the predictive value of cancer significance.

CONCLUSIONS

These findings indicate that clinicopathological findings suggesting favorable features are well observed in patients with potentially insignificant prostate cancer compared to those with significant prostate cancer, and the combination of a biopsy Gleason score <7 and PPBC <15% might be useful as a predictor of insignificant disease.

Pathological and molecular aspects of prostate cancer

This review focuses on new findings and controversial issues in the the pathology and molecular biology of adenocarcinoma of the prostate. Since management of high-grade prostatic intraepithelial neoplasia on needle biopsy--the most common precursor lesion to prostate cancer--is the crucial issue with this lesion, we discuss the risk of cancer subsequent to this histological diagnosis and the issue of whether such neoplasia should be regarded as carcinoma-in-situ. We also look at prostate cancer itself, starting with its diagnosis, reporting on needle biopsy, and reviewing how the most frequently used grading system, the Gleason grading system, affects treatment. The molecular basis of prostate cancer includes inheritable and somatic genetic changes (tumour suppressor genes, loss of heterozygosity, gene targets and regions of chromosomal gain, CpG island promoter methylation, invasion and metastasis suppressor genes, telomere shortening, and genetic instability). Changed gene expression (eg, proliferation-related genes, changes in the androgen receptor, apoptosis and stress-response genes) have potential as biomarkers and therapeutic targets in prostate cancer.