An algorithm for prostate cancer detection in a patient population using prostate-specific antigen and prostate-specific antigen density

Potential diagnostic value of multiple indicators combined with total prostate-specific antigen in prostate cancer

OBJECTIVE

We aimed to investigate the diagnostic value of different laboratory indicators in combination with total prostate-specific antigen (TPSA) for prostate cancer (PCa).

METHODS

In this retrospective study, we selected 291 patients who underwent prostate biopsy. Patients were divided into the benign prostatic hyperplasia group and the PCa group. In both groups, patients were again divided into a group with TPSA 4.0-10.0 ng/mL and a group with TPSA >10.0 ng/mL. Clinical data including age, pre-puncture TPSA, free prostate-specific antigen (FPSA), and prostate volume (PV) were collected from all patients. We calculated the metrics PSA/PV (prostate-specific antigen density, PSAD), age/PV (AVR), age × PV/TPSA (PSA-AV), and (FPSA/TPSA)/PSAD [(F/T)/PSAD]). We plotted receiver operating characteristic (ROC) curves and calculated the area under the ROC curve (AUC).

RESULTS

We found statistically significant differences in PV, PSAD, AVR, PSA-AV, and (F/T) PSAD for patients with TPSA 4.0-10.0 ng/mL and TPSA >10 ng/mL. We further plotted the ROC of individual or combined indices in different subgroups and calculated the AUC. We found that the diagnostic efficacy of the combined indices was higher with TPSA >10 ng/mL.

CONCLUSION

The combination of TPSA with multiple indicators may improve diagnostic accuracy for PCa.

Combining clinical parameters and multiparametric magnetic resonance imaging to stratify biopsy-naïve men for an optimum diagnostic strategy with prostate-specific antigen 4 ng ml-1 to 10 ng ml-1

We attempted to perform risk categories based on the free/total prostate-specific antigen ratio (%fPSA), prostate-specific antigen (PSA) density (PSAD, in ng ml-2), and multiparametric magnetic resonance imaging (mpMRI) step by step, with the goal of determining the best clinical diagnostic strategy to avoid unnecessary tests and prostate biopsy (PBx) in biopsy-naïve men with PSA levels ranging from 4 ng ml-1 to 10 ng ml-1. We included 439 patients who had mpMRI and PBx between August 2018 and July 2021 (West China Hospital, Chengdu, China). To detect clinically significant prostate cancer (csPCa) on PBx, receiver-operating characteristic (ROC) curves and their respective area under the curve were calculated. Based on %fPSA, PSAD, and Prostate Imaging-Reporting and Data System (PI-RADS) scores, the negative predictive value (NPV) and positive predictive value (PPV) were calculated sequentially. The optimal %fPSA threshold was determined to be 0.16, and the optimal PSAD threshold was 0.12 for %fPSA ≥0.16 and 0.23 for %fPSA <0.16, respectively. When PSAD <0.12 was combined with patients with %fPSA ≥0.16, the NPV of csPCa increased from 0.832 (95% confidence interval [CI]: 0.766-0.887) to 0.931 (95% CI: 0.833-0.981); the detection rate of csPCa was similar when further stratified by PI-RADS scores (P = 0.552). Combining %fPSA <0.16 with PSAD ≥0.23 ng ml-2 predicted significantly more csPCa patients than those with PSAD <0.23 ng ml-2 (58.4% vs 26.7%, P < 0.001). Using PI-RADS scores 4 and 5, the PPV was 0.739 (95% CI: 0.634-0.827) when further stratified by mpMRI results. In biopsy-naïve patients with PSA level of 4-10 ng ml-1, stratification of %fPSA and PSAD combined with PI-RADS scores may be useful in the decision-making process prior to undergoing PBx.

Prostate Health Index Density Outperforms Prostate Health Index in Clinically Significant Prostate Cancer Detection

Background

Prostate-specific antigen (PSA) is considered neither sensitive nor specific for prostate cancer (PCa). We aimed to compare total PSA (tPSA), percentage of free PSA (%fPSA), the PSA density (PSAD), Prostate Health Index (PHI), and the PHI density (PHID) to see which one could best predict clinically significant prostate cancer (csPCa): a potentially lethal disease.

Methods

A total of 412 men with PSA of 2-20 ng/mL were prospectively included. Serum biomarkers for PCa was collected before transrectal ultrasound guided prostate biopsy. PHI was calculated by the formula: (p2PSA/fPSA) x √tPSA. PHID was calculated as PHI divided by prostate volume measured by transrectal ultrasound.

Results

Of the 412 men, 134 (32.5%) and 94(22.8%) were diagnosed with PCa and csPCa, respectively. We used the area under the receiver operating characteristic curve (AUC) and decision curve analyses (DCA) to compare the performance of PSA related parameters, PHI and PHID in diagnosing csPCa. AUC for tPSA, %fPSA, %p2PSA, PSAD, PHI and PHID were 0.56、0.63、0.76、0.74、0.77 and 0.82 respectively for csPCa detection. In the univariate analysis, the prostate volume, tPSA, %fPSA, %p2PSA, PHI, PSAD, and PHID were all significantly associated with csPCa, and PHID was the most important predictor (OR 1.41, 95% CI 1.15-1.72). Besides, The AUC of PHID was significantly larger than PHI in csPCa diagnosis (p=0.004). At 90% sensitivity, PHID had the highest specificity (54.1%) for csPCa and could reduce the most unnecessary biopsies (43.7%) and miss the fewest csPCa (8.5%) when PHID ≥ 0.67. In addition to AUC, DCA re-confirmed the clinical benefit of PHID over all PSA-related parameters and PHI in csPCa diagnosis. The PHID cut-off value was positively correlated with the csPCa ratio in the PHID risk table, which is useful for evaluating csPCa risk in a clinical setting.

Conclusion

The PHID is an excellent predictor of csPCa. The PHID risk table may be used in standard clinical practice to pre-select men at the highest risk of harboring csPCa.

The use of prostate specific antigen density to predict clinically significant prostate cancer

The purpose of this study was to assess the predictive value of prostate specific antigen density (PSAD) for detection of clinically significant prostate cancer in men undergoing systematic transrectal ultrasound (TRUS)-guided prostate biopsy. We retrospectively analyzed data of men who underwent TRUS-guided prostate biopsy because of elevated PSA (≤ 20 ng/ml) or abnormal digital rectal examination. Receiver operating characteristic curve analysis to compare PSA and PSAD performance and chi-square automatic interaction detector methodologies were used to identify predictors of clinically significant cancer (Gleason score ≥ 7 or international society of urological pathology grade group ≥ 2). Nine-hundred and ninety-two consecutive men with a median age of 66 years (IQR 61-71) were included in the study. Median PSAD was 0.10 ng/ml² (IQR 0.10-0.22). Prostate adenocarcinoma was diagnosed in 338 men (34%). Clinically significant prostate adenocarcinoma was diagnosed in 167 patients (50% of all cancers and 17% of the whole cohort). The AUC to predict clinically significant prostate cancer was 0.64 for PSA and 0.78 for PSAD (P < 0.001). The highest Youden's index for PSAD was at 0.20 ng/ml² with 70% sensitivity and 79% specificity for the diagnosis of clinically significant cancer. Men with PSAD < 0.09 ng/ml² had only 4% chance of having clinically significant disease. The detection rate of clinically significant prostate cancer in patients with PSAD between 0.09 and 0.19 ng/ml² was significantly higher when prostate volume was less than 33 ml. In conclusion, PSAD was a better predictor than PSA alone of clinically significant prostate cancer in patients undergoing TRUS-guided biopsy. Patients with PSAD below 0.09 ng/ml² were unlikely to harbor clinically significant prostate cancer. Combining PSAD in the gray zone (0.09-0.19) with prostate volume below 33 ml adds diagnostic value of clinically significant prostate cancer.

Clinical significance of multiparametric MRI and PSA density as predictors of residual tumor (pT0) following radical prostatectomy for T1a-T1b (incidental) prostate cancer

Purpose

The aim of this study was to evaluate predictors of residual tumor and clinical prognosis in T1a-T1b (incidental) prostate cancer by analysis of specimens from men undergoing surgery for benign prostatic hyperplasia.

Materials and methods

We retrospectively reviewed medical records of incidental prostate cancer patients who had undergone radical prostatectomy. Patients whose tumor statuses were further confirmed by prostate biopsy, or who had used androgen deprivation therapy before radical prostatectomy, were excluded. Clinical and pathological parameters were analyzed to evaluate residual tumor and clinical prognosis. We used univariate and multivariate logistic regression analyses, as well as receiver operator characteristics, to predict residual tumor (pT0).

Results

The final analysis included 95 patients. Among these patients, 67 (70.53%) exhibited residual tumor, whereas 28 (29.47%) did not (pT0). Pathology findings showed that 44 (65.67%), 16 (23.88%), and 7 patients (10.45%) exhibited Gleason scores of G6, G7, and ≥G8, respectively. Fifty-seven and 10 patients exhibited pathologic T stages T2 and T3, respectively. Mean follow-up duration was 70.26 (±34.67) months. Biochemical recurrence was observed in 11 patients; none were pT0 patients. Multivariate logistic regression showed that low prostate-specific antigen density after benign prostatic hyperplasia surgery and invisible lesion on multiparametric magnetic resonance imaging were significantly associated with pT0. Additionally, a combination of these factors showed an increase in the diagnostic accuracy of pT0, compared with mpMRI alone (AUC 0.805, 0.767, respectively); this combination showed sensitivity, specificity, and positive predictive values of 71.6%, 89.3%, and 94.1%, respectively.

Conclusion

Our results suggest that patients with incidental prostate cancer who have both prostate-specific antigen density ≤0.08 after benign prostatic hyperplasia surgery as well as invisible cancer lesion on multiparametric magnetic resonance imaging should be considered for active surveillance.

Prostate Specific Antigen Density as a Predictor of Clinically Significant Prostate Cancer When the Prostate Specific Antigen is in the Diagnostic Gray Zone: Defining the Optimum Cutoff Point Stratified by Race and Body Mass Index

PURPOSE

We assessed the predictive value of prostate specific antigen density to detect clinically significant prostate cancer, defined as prostate cancer grade group 2 or greater, in a series of men undergoing prostate biopsy with prostate specific antigen 4 to 10 ng/ml. We sought to define an optimum cutoff point for prostate specific antigen density and assess how race and body mass index affects prostate specific antigen density performance.

MATERIALS AND METHODS

We analyzed data on 2,162 men, of whom 56% were African American, with serum prostate specific antigen 4 to 10 ng/ml who underwent prostate biopsy. We compared the AUC between prostate specific antigen and prostate specific antigen density to predict clinically significant and any prostate cancer vs no cancer. We calculated the negative predictive value of prostate specific antigen density cutoff points ranging from 0.05 to 0.15 by every 0.01 step. We a priori defined the optimal cutoff point of prostate specific antigen density as a negative predictive value of 95% and tested whether the cutoff was sensitive to body mass index and race by comparing the negative predictive value across strata.

RESULTS

Median prostate specific antigen was 5.6 ng/ml (IQR 4.8-7) and median prostate specific antigen density was 0.15 ng/ml/cc (IQR 0.1-0.22). Prostate specific antigen density improved the performance of prostate specific antigen to detect significant cancer (AUC 0.58 to 0.68) and any cancer (AUC 0.55 to 0.69, each p <0.001). We identified a prostate specific antigen density cutoff point of less than 0.08 ng/ml/cc with a 96% negative predictive value for grade group 2 or greater. This was largely unchanged among different races and body mass indexes.

CONCLUSIONS

Regardless of race or body mass index men with prostate specific antigen density less than 0.08 were unlikely to harbor grade group 2 or greater disease when prostate specific antigen was 4 to 10 ng/ml. If validated, prostate specific antigen density is a simple inexpensive and available tool that can be used to identify men who can likely forego prostate biopsies, thus reducing the over detection and morbidity of unnecessary biopsies.

Re-examining Prostate-specific Antigen (PSA) Density: Defining the Optimal PSA Range and Patients for Using PSA Density to Predict Prostate Cancer Using Extended Template Biopsy

OBJECTIVE

To compare the predictive accuracy of prostate-specific antigen (PSA) density vs PSA across different PSA ranges and by prior biopsy status in a prospective cohort undergoing prostate biopsy.

MATERIALS AND METHODS

Men from a prospective trial underwent an extended template biopsy to evaluate for prostate cancer at 26 sites throughout the United States. The area under the receiver operating curve assessed the predictive accuracy of PSA density vs PSA across 3 PSA ranges (<4 ng/mL, 4-10 ng/mL, >10 ng/mL). We also investigated the effect of varying the PSA density cutoffs on the detection of cancer and assessed the performance of PSA density vs PSA in men with or without a prior negative biopsy.

RESULTS

Among 1290 patients, 585 (45%) and 284 (22%) men had prostate cancer and significant prostate cancer, respectively. PSA density performed better than PSA in detecting any prostate cancer within a PSA of 4-10 ng/mL (area under the receiver operating characteristic curve [AUC]: 0.70 vs 0.53, P < .0001) and within a PSA >10 mg/mL (AUC: 0.84 vs 0.65, P < .0001). PSA density was significantly more predictive than PSA in detecting any prostate cancer in men without (AUC: 0.73 vs 0.67, P < .0001) and with (AUC: 0.69 vs 0.55, P < .0001) a previous biopsy; however, the incremental difference in AUC was higher among men with a previous negative biopsy. Similar inferences were seen for significant cancer across all analyses.

CONCLUSION

As PSA increases, PSA density becomes a better marker for predicting prostate cancer compared with PSA alone. Additionally, PSA density performed better than PSA in men with a prior negative biopsy.

Prostate-Specific Antigen (PSA) and Prostate Volume: Better Predictor of Prostate Cancer for Bosnian and Herzegovina Men

Background:

The serum prostate specific antigen for the early detection and screening for prostate cancer are very common used among physicians as the best screening tool for prostate cancer. The result of prostate specific antigen levels discriminates whether or not a prostate biopsy should be performed. The lack of specificity is a limitation of PSA as tumor marker, increased PSA concentrations are found not only in patients with prostate cancer but also in patients with benign prostatic disease. The object of this study was to improve the specificity and sensitivity of prostatic cancer detection. We evaluated total PSA levels, free PSA levels and the prostate volume in asymptomatic patients which came for routine check without medical history of prostate cancer.

Methods:

We received medical record of 90 patients between 50-60 years. Total and free PSA in serum was measured with the analyzer Architeckt i2000 SR. Prostate volume was determined by transrectal ultrasound.

Results :

The ratio of total and free PSA levels to prostate volume was significantly (p < 0.001) between all three groups. It was observed that increased prostate volume correlates with increased level of total and free PSA in serum.

Conclusion:

Early studies have demonstrated the advantage of measuring prostate volume with PSA total and free levels in serum as a useful tool for early diagnosis of prostate cancer. Data from this study on 90 patients with total PSA in the range from 0,22-7,0 ng/ml confirmed the well known correlation. All three parameters total PSA, free PSA and prostate volume showed significant correlation and a useful tool in prediction of prostate cancer for Bosnia and Herzegovina men.

Incidental Prostate Cancer Diagnosis During Holmium Laser Enucleation: Assessment of Predictors, Survival, and Disease Progression

OBJECTIVE

To determine the prevalence and predictors of incidental prostate cancer (IPCa) after Holmium laser enucleation of the prostate (HoLEP) and to assess its functional and oncological outcomes.

METHODS

A prospectively maintained database was reviewed for cases with IPCa at the time of HoLEP. Patients with preoperative PCa were excluded. Patients were divided into two groups based on the presence (group I [GI]) or absence of cancer (group II [GII]) in histopathology. Univariate and multivariate logistic regression analyses were performed.

RESULTS

Of 1242 patients, 70 (5.64%) were identified to have IPCa. Prostate size was comparable between both groups. GI patients had significantly higher preoperative prostate-specific antigen (PSA) and total PSA density (tPSAD) compared to cancer-free patients. T1a and T1b adenocarcinomas were detected in 54 (77.1%) and 16 (22.9%) patients, respectively. After a median follow-up of 48 (1-171) months, both groups were comparable in all functional outcomes but the quality of life was significantly better in GII. Patients' age and preoperative tPSAD independently predicted IPCa after HoLEP. A tPSAD cutoff value of 0.092 has a sensitivity and specificity of 0.83 and 0.67, respectively. Seven patients (11.7%) needed adjuvant therapy while other GI patients opted for active surveillance. The Kaplan-Meier analysis demonstrated an overall survival of 72.8% at 5 years and 63.5% at 10 years for patients with PCa.

CONCLUSION

PCa is not uncommonly identified after HoLEP, even in those with negative preoperative biopsies. In older patients, total PSAD could be a predictor using a cutoff <0.1. After HoLEP, active surveillance for low-grade PCa carries good functional and oncological outcomes.

Prostate Specific Antigen as a Tumor Marker in Prostate Cancer: Biochemical and Clinical Aspects

In this chapter the use of prostate specific antigen (PSA) as a tumor marker for prostate cancer is discussed. The chapter provides an overview of biological and clinical aspects of PSA. The main drawback of total PSA (tPSA) is its lack of specificity for prostate cancer which leads to unnecessary biopsies. Moreover, PSA-testing poses a risk of overdiagnosis and subsequent overtreatment. Many PSA-based markers have been developed to improve the performance characteristics of tPSA. As well as different molecular subforms of tPSA, such as proPSA (pPSA) and free PSA (fPSA), and PSA derived kinetics as PSA-velocity (PSAV) and PSA-doubling time (PSADT). The prostate health index (phi), PSA-density (PSAD) and the contribution of non PSA-based markers such as the urinary transcripts of PCA3 and TMPRSS-ERG fusion are also discussed. To enable further risk stratification tumor markers are often combined with clinical data (e.g. outcome of DRE) in so-called nomograms. Currently the role of magnetic resonance imaging (MRI) in the detection and staging of prostate cancer is being explored.

The Use and Misuse of the PSA Test: A Retrospective Case Note Review of Testing in a UK Teaching Hospital

Introduction:

PSA testing is commonly performed by non-urological specialties in the hospital setting. The indications for requesting a PSA test can vary widely in this group and may not always be appropriate. This may generate unnecessary patient anxiety and additional testing. This study was designed to assess the appropriateness of PSA requests by non-urologists in the hospital setting.

Methods:

A computer search for patient details of all PSA requests within a 3 month period by non-urologists was generated by the pathology department. 130 consecutive case notes were then reviewed of which 95 met the inclusion criteria. The reason for each request was then determined to be appropriate or inappropriate according to standard urological practice.

Results:

95 patients were included. Of these, 61 (64%) requests were made by medical specialties, 17 (18%) were requested by orthopaedics, 12 (13%) by general surgery and the remaining 5 (5%) by other specialties. There were 26 (27%) requests deemed appropriate and 69 (73%) inappropriate. Of the inappropriate requests in 52 cases no reason was given, 14 were made immediately after acute urinary retention and 9 were during a suspected urinary infection. A rectal examination was performed in conjunction with the test in 24 cases.

Conclusion:

In this setting the majority of PSA requests made by non-urologists was inappropriate. This may be due to a lack of knowledge of the indication for PSA testing and the factors which may cause a false positive result. There was a low level of rectal examination. More education is needed to improve this situation.

Two-dimensional spectroscopic imaging for pretreatment evaluation of prostate cancer: comparison with the step-section histology after radical prostatectomy

PURPOSE

To minimize user and vendor dependence of the spectrum processing of prostate spectra, to measure the ratio of choline (Cho) plus creatine (Cr) to citrate (Cit) in the prostate tissue of normal volunteers and cancer patients, and to compare the results with pathologic findings after radical prostatectomy.

MATERIALS AND METHODS

Four healthy volunteers and 13 patients with prostate cancer were measured. Measurements were performed using two-dimensional magnetic resonance spectroscopic imaging (MRSI) and endorectal coil. A standard vendor's spectrum processing approach has been modified. An original feature of this methodology was the combination of vendor-optimized and user-independent spectrum preprocessing in the scanner and user-independent quantitation in the environment of an MRUI software package. (Cho+Cr)/Cit ratio was used for the classification of prostate tissue. Results were compared with histopathology after radical prostatectomy.

RESULTS

Eight of 13 cancer patients were classified as suspicious or very suspicious for cancer at spectroscopy, three were ambiguous for cancer and two patients were evaluated as false negative. A considerable overlap of metabolite ratios at various Gleason score was found.

CONCLUSION

The proposed spectrum processing has the potential to improve the accuracy and user independency of the (Cho+Cr)/Cit quantitation. This study confirmed the previous results that a considerable overlap of (Cho+Cr)/Cit ratios exists at various Gleason score levels.

The ratio of prostate-specific antigen (PSA) to prostate volume (PSA density) as a parameter to improve the detection of prostate carcinoma in PSA values in the range of < 4 ng/mL

BACKGROUND

The objective of this study was to evaluate the prostate specific antigen (PSA) density (PSAD) (the quotient of PSA and prostate volume) compared with the percent free PSA (%fPSA) in different total PSA (tPSA) ranges from 2 ng/mL to 20 ng/mL. Possible cut-off levels depending on the tPSA should be established.

METHODS

In total, 1809 men with no pretreatment of the prostate were enrolled between 1996 and 2004. Total and free PSA were measured with the IMMULITE PSA and Free PSA kits (Diagnostic Products, Los Angeles, CA). Prostate volume was determined by transrectal ultrasound. The diagnostic validity of tPSA, %fPSA, and PSAD was evaluated by receiver operation characteristic (ROC) curve analysis.

RESULTS

The PSAD differed significantly (P < 0.0001) between patients with prostate carcinoma and patients with benign prostatic hyperplasia in all analyzed ranges of tPSA and prostate volume. At the 90% and 95% sensitivity levels and regarding the area under the ROC curve (AUC) within the tPSA range of 2-4 ng/mL, The PSAD was significantly better than tPSA and %fPSA. Within the tPSA range of 4-10 ng/mL, the PSAD did not perform better than %fPSA.

CONCLUSIONS

PSAD showed a better performance than %fPSA at tPSA concentrations < 4 ng/mL for detecting prostate carcinoma, with a significantly larger AUC for PSAD (0.739) compared with %fPSA (0.667). PSAD did not perform better than %fPSA when the tPSA range of 4-10 ng/mL was analyzed. Different PSAD cut-off values of 0.05 at tPSA 2-4 ng/mL, 0.1 at tPSA 4-10 ng/mL, and 0.19 at 10-20 ng/mL were necessary to reach 95% sensitivity.

Predictors of prostate carcinoma: accuracy of gray-scale and color Doppler US and serum markers

PURPOSE

To determine the accuracy of detecting prostate cancer by using (a) gray-scale and color Doppler transrectal ultrasonography (US), (b) serum and excess prostate-specific antigen (PSA) levels, and (c) targeted and sextant transrectal US-guided biopsy. The relationship between US-detected neovascularity and tumor biologic activity was also evaluated.

MATERIALS AND METHODS

Between 1995 and 1999, 544 patients with elevated PSA levels and/or abnormal digital rectal examination underwent transrectal US-guided sextant biopsy and targeted biopsy of US abnormalities. Sensitivity, specificity, and accuracy of gray-scale US, color Doppler US, targeted biopsy, and PSA and excess PSA were calculated.

RESULTS

Gray-scale US depicted 78 (41.1%) of 190 cancers, whereas color Doppler US depicted 30 (15.8%) additional cancers. Targeted biopsy was used to detect 108 (56.8%) cancers, whereas sextant biopsy was used to detect 82 (43.2%) additional cancers. Although US-visible cancers had a higher Gleason grade than did cancers discovered at sextant biopsy (P <.05), 25 of the 66 cancers identified with sextant biopsy alone were Gleason grade 6 or higher. Color Doppler US-depicted hypervascularity correlated with biologically aggressive tumors. Excess PSA was normal in 58 (30.5%) cancers, with an accuracy of 67.3%, resulting in better prediction of prostate tumors than with serum PSA level alone.

CONCLUSION

Gray-scale transrectal US, even coupled with color Doppler US, is inadequate for prostate carcinoma screening; therefore, targeted biopsy should always be accompanied by complete sextant biopsy sampling.

Volume-specific cutoffs are necessary for reproducible application of prostate-specific antigen density of the transition zone in prostate cancer detection

OBJECTIVES

To determine the effect of prostate volume on the specificity of prostate-specific antigen density (PSAD) and PSAD of the transition zone (PSA-TZ) in the detection of prostate cancer.

METHODS

Between February 1994 and April 1998, transrectal ultrasound-guided prostate needle biopsies were performed in 235 men with serum prostate-specific antigen (PSA) levels between 4.0 and 10.0 ng/mL. The PSAD and PSA-TZ specificities were calculated at 95% sensitivity cutoff levels generated from the whole group, as well as from cohorts stratified by transition zone index or prostate volume.

RESULTS

Statistical significance was noted between the benign (n = 176) and prostate cancer (n = 59) groups for all tested PSA parameters. At 95% sensitivity, PSA-TZ carried a specificity of 37.5% compared with 29.6% for PSAD. When applying a single 95% sensitivity cutoff derived from the entire group to individual volume-stratified cohorts, the specificity decreased to 0% in glands less than 30 g in size. A 95% sensitivity PSA-TZ cutoff generated individually for volume-stratified cohorts of glands less than 30, 30 to 40, and 40 to 60 g resulted in more consistent specificity of 28.2%, 35.2%, and 45.7% for each cohort, respectively.

CONCLUSIONS

Unlike whole group-derived cutoffs, the use of volume-specific PSA-TZ cutoffs allows consistently high specificity in all volume-stratified cohorts. The discrepancies in the PSA-TZ and PSAD specificities in published reports are likely due to the application of published cutoffs to populations of differing prostate volumes. The use of volume-specific cutoffs results in reproducible specificity in populations with differing prostate volume distribution, and thereby definitively resolves the differences in PSA-TZ specificity reported in published reports.

The necessity of a second prostate biopsy cannot be predicted by PSA or PSA derivatives (density or free:total ratio) in men with prior negative prostatic biopsies

Serum prostate specific antigen, prostate specific antigen density and free:total prostate specific antigen are known to be useful for determining the risk of prostate cancer in patients undergoing prostate cancer screening. The patient with a positive biopsy presents no future prostate specific antigen dilemma. Those with negative biopsies often go on to numerous repeat biopsies. Our goal was to establish criteria that could be used to identify patients who will require repeat prostate biopsies (possibly false negative initial biopsy), while not exposing the low risk population (probable true negative initial biopsy) to additional invasive procedures. Between March 1991 and March 1998, 148 patients who had a biopsy for an elevated prostate specific antigen value (4.1-10.0) or an altered digital rectal examination, had no cancer found in the specimen. From these, 51 (34.4%) had repeated biopsies, while the others persisted on close follow-up. We examined their serum prostate specific antigen, prostate specific antigen density and free:total prostate specific antigen value, as well as their age and histology results of the initial and repeat biopsy, to determine if any predictor of the need for a repeat biopsy could be identified. Eight (15.7%) from 51 men who had repeat biopsy had prostate cancer detected. Forty three (84.3%) patients persisted with a negative biopsy, despite filling the criteria for re-biopsy. Multivariate analysis failed to identify any significant predictors of prostate cancer in the repeat biopsy group. Despite initial success, the prostate specific antigen derivatives and free:total prostate specific antigen have not safely limited the number of biopsies performed for an abnormal prostate specific antigen (4.1-10.0). Neither prostate specific antigen density nor free:total prostate specific antigen predicted the need for repeat biopsy in this specific group. The results of this ongoing study demonstrate that to date, prostate specific antigen and prostate specific antigen derivatives can not be utilized to determine which patients will be at high risk for requiring repeat prostate biopsy. All patients must be closely monitored for evidence of a change in status from benign to malignant disease, and new markers for this purpose are urgently needed.

Prostate-specific antigen (PSA), PSA density and age-adjusted PSA reference values in screening for prostate cancer--a study of a randomly selected population of 2,400 men

Prostate cancer screening with DRE, TRUS, and PSA testing was offered to 2,400 randomly selected men 55-70 years old. Among 1,782 examined, 65 (3.6%) men with prostate cancer were diagnosed. The PSA results were correlated to the diagnosis, the men's age, and the prostate volume. Least square regression analysis was used to calculate the 95% upper confidence intervals for PSA in each year of age in men without prostate cancer. The PPV was calculated for: (i) PSA > 4 ng/ml, (ii) PSAD > 0.15, (iii) PSAD > 0.20 and (iv) age-adjusted PSA reference values. A significant correlation was found between PSA and prostate volume, between PSA and age, and between the prostate volume and age. The calculated annual growth of the prostate was 1.6% and the annual increase in PSA was 2.4%. The age-adjusted upper PSA reference values for the three age categories studied (55-59, 60-64 and 65-70 years) were 5.2, 5.8, and 6.7 ng/ml, respectively. The PPVs for PSA > 4 ng/ml, PSAD > 0.15, PSAD > 0.20, and the age-adjusted PSA reference values were 17%, 14%, 22%, and 27%, respectively. Age-adjusted PSA or PSAD may increase the PPV compared to PSA > 4 ng/ml. The detection rate is, however, inadequate. A PSA cut-off at 4 ng/ml could therefore be maintained in men 55-70 years old. The median PSA values and median prostate volumes calculated for men with benign findings may serve as a reference in future studies.

The usefulness of prostate-specific antigen (PSA) density in patients with intermediate serum PSA level in a country with low incidence of prostate cancer

OBJECTIVES

To evaluate if a calculated PSA density (PSAD) prior to biopsy could be useful to determine the need for prostate biopsies in patients with serum PSA levels of 4.1-20.0 ng/mL in a country with low incidence of prostate cancer (PCa).

METHODS

A total of 185 consecutive patients aged 50-79 years who underwent prostate biopsies were evaluated by correlating the biopsy results with the results of digital rectal examination (DRE), transrectal ultrasonography (TRUS), serum PSA levels, and PSAD. Prostate volume was calculated from TRUS using prolate ellipse formula and PSAD was obtained by dividing serum PSA level by prostate volume.

RESULTS

In this study population, 27 cases (14.6%) had positive biopsies. Of 158 cases with negative biopsies, 43 (23.2%) had histologically verified prostatic inflammation. The diagnostic value of DRE and TRUS was hampered by unsatisfactory sensitivity and specificity in differentiating patients with positive biopsies from those with negative biopsies. The use of PSAD alone as an indicator for biopsy was also limited by its low specificity. A PSAD cutoff value of 0.15 resulted in a sensitivity of 100% and a specificity of only 12%. Prostatic inflammation was a confounding factor for the inadequate specificity of DRE, TRUS and PSAD. Combined use of DRE and PSAD provided the best information regarding the need for biopsies. Accordingly, if the 47 patients (25.4%) who presented with both a negative DRE and a PSAD < or = 0.20 were not biopsied, the rate of positive biopsy could have increased to 19.6% (27 of 138) without missing any cancer detection.

CONCLUSIONS

It is concluded from this study that for patients with serum PSA levels of 4.1-20.0 ng/mL, biopsies should only be recommended for those with abnormal DRE and/or PSAD >0.20.

Standardized assessment to enhance the diagnostic value of prostate volume; Part I: Morphometry in patients with lower urinary tract symptoms

BACKGROUND

The diagnostic value of prostate volume results has been evaluated in patients with prostate problems of benign cause.

METHODS

For 247 patients, automated volume results were compared to manual results of planimetric reference volume and of the classical ellipsoid formula. Also, transition zone volume was estimated and growth curves of the prostate and prostate dimensions over age were investigated.

RESULTS

Application of automated volume determination gives accurate results compared to the reference volume (Pearson correlation, R = 0.938). The ellipsoid volume results were slightly less correlated (R = 0.921). Average growth of the entire prostate was 1.7% per year, for the transition zone the growth was 4.3%. Compared to growth rates for a community-based population, comparable growth rates were found for our group that had higher mean prostate volume.

CONCLUSIONS

The results indicate that the age of onset of volume growth is the determining factor in developing benign prostate enlargement not a change in growth rate.

Standardized assessment to enhance the diagnostic value of prostate volume; Part II: Correlation with prostate-specific antigen levels

BACKGROUND

Standardized estimations of prostate volumes are used for interpretation of prostate specific antigen (PSA) levels.

METHODS

In 243 patients with clinically benign diagnosis, automated and reference prostate volumes and transition zone volumes are correlated to PSA levels. Besides, growth curves of PSA level when aging are determined.

RESULTS

The strongest correlation was found with multiple regression analysis between PSA and transition zone volume and rest volume (R = 0.854). Mean PSA density was 0.092 ng/mL2, its labelling quality for benign disease was 91% (threshold = 0.15 ng/mL2). An average growth factor for PSA levels of 2.9% per year was obtained.

CONCLUSIONS

The contribution per unit tissue to PSA level was for the transition zone 1.9 times higher than for the rest volume. Average growth of PSA per year is in consonance with the increase in normal levels of age specific PSA ranges, although only weak correlations were found between PSA and age and PSA density and age.

Comparative analysis of prostate specific antigen and its indexes in the detection of prostate cancer

PURPOSE

Prostate specific antigen (PSA) density and age referenced PSA have been proposed in an attempt to improve the power of PSA in the detection of early prostate cancer. Reported results have been controversial and disappointing. Because the association of gland volume with PSA is stronger than that of age we developed a new index, volume referenced PSA, and compared it to PSA density and other indexes.

MATERIALS AND METHODS

Volume referenced PSA was developed from a control group of 408 men without clinical evidence of prostate cancer using a standardized Z score. A retrospective analysis was performed comparing PSA and all its indexes in 580 men who underwent prostate biopsy. In addition to overall analysis, PSA and its indexes were evaluated with receiver operating characteristic curves by age and volume subcategories.

RESULTS

Cancer was identified in 35% of the 580 men. The number of missed cancers using established thresholds significantly favored volume referenced PSA clinically and statistically compared to all other indexes but it was equivalent to PSA alone clinically. Age referenced PSA prevented more biopsies from being done than did volume referenced PSA (39% versus 31%) but resulted in the diagnosis of 48% fewer cancers. Receiver operating characteristic curve analysis demonstrated a significantly better performance for volume referenced PSA and PSA density compared to PSA alone and age referenced PSA.

CONCLUSIONS

Volume based PSA indexes are superior to PSA and age referenced PSA statistically. However, clinically volume referenced PSA is comparable to PSA, and both are superior to age referenced PSA and PSA density in the detection of prostate cancer.

Acid phosphatase: defining a role in androgen-independent prostate cancer

OBJECTIVES

In multivariable analysis, post-therapy change in prostate-specific antigen (PSA) was shown to be the most significant factor predictive of survival in patients with androgen-independent prostate cancer. To refine the model, we studied the patterns of change in acid phosphatase, alkaline phosphatase, and lactate dehydrogenase after treatment.

METHODS

One hundred seven patients with androgen-independent prostate cancer treated on seven different protocols in Memorial Sloan-Kettering Cancer Center were evaluated. For tumor-specific (acid phosphatase and PSA) and nontumor-specific (alkaline phosphatase and lactate dehydrogenase) enzymes, a minimum 50% or 80% decrease from baseline documented on three separate occasions a minimum of 6 weeks apart was required to categorize a patient as having a decline.

RESULTS

Nineteen patients (18%) had either a 50% decline in acid phosphatase or PSA, of whom 13 (68%) had a decline of both markers. Six (32%) patients showed discordance between the two parameters. Declines in PSA level typically preceded declines in acid phosphatase levels. The median survival of patients showing declines in both markers exceeded that of patients showing declines in PSA alone by 1 year. Although baseline measurements of alkaline phosphatase or lactate dehydrogenase did add additional prognostic information, post-therapy changes did not.

CONCLUSIONS

Post-therapy declines in PSA and acid phosphatase represent reproducible endpoints for clinical trials in androgen-independent disease. The requirement of a repeated and parallel decline in both markers may improve the results observed by monitoring declines in PSA alone. Monitoring the two parameters may allow the development of models that can be used as surrogate endpoints for response and survival in a disease in which reproducible measurements of response are lacking.

Prostate-specific antigen density: correlation with histological diagnosis of prostate cancer, benign prostatic hyperplasia and prostatitis

OBJECTIVE

To assess the additional value of prostate-specific antigen density in the diagnosis of prostate cancer in patients who undergo prostate biopsies.

PATIENTS AND METHODS

The study comprised 376 patients with symptoms of prostatism who were undergoing prostate biopsy. Digital rectal examination (DRE) and transrectal ultrasonography (TRUS) were performed and the prostate specific antigen level (PSA) and density (PSAD) were determined for each patient.

RESULTS

Both PSA and PSAD significantly differentiated (P < 0.001) between benign and malignant histology. Of the 376 patients, 91 (24%) had a PSA level in the intermediate range (4.0-10.0 ng/mL). In these patients PSAD was significantly better than PSA in differentiating between benign and malignant histology (P = 0.027 vs 0.316). With a PSAD limit of 0.15 ng/mL/cm3 in these patients, the sensitivity was 92% and the specificity was 54% for the diagnosis of prostate cancer. No patient with a positive biopsy had a PSAD < 0.11 ng/mL/cm3. No limiting value could be found for PSAD that combined both an acceptable sensitivity and specificity. Of the patients with a malignancy detected by the biopsy, 92% also had a suspect DRE.

CONCLUSION

In patients with intermediate PSA levels, PSAD is of limited additional value when compared to DRE in correctly diagnosing prostate cancer. Acute prostatitis is also a possible cause of elevated PSA. Both PSA and PSAD had no additional value in differentiating between benign prostatic hyperplasia (BPH) and histologically proven extensive prostatitis.

Evaluation of patients with diseases of the prostate using prostate-specific antigen density

OBJECTIVE

To compare the efficacy of two tests, prostatic-specific antigen (PSA) and the PSA/prostate volume ratio (PSAD), as diagnostic and staging markers to discriminate patients with benign prostatic hyperplasia (BPH) from patients with cancer of the prostate (CaP).

PATIENTS AND METHODS

Prostate gland volumes were estimated in 60 patients with BPH and 88 patients with clinically organ-confined CaP by performing transrectal ultrasonography (TRUS) and using the prolate ellipse formula. Serum PSA concentration was determined using an enzyme immunoassay. In patients with BPH, the prostates were removed either by transurethral resection or retropubic prostatectomy. Patients with CaP underwent laparoscopic pelvic lymphadenectomy followed by radical perineal prostatectomy. PSAD was calculated by relating the serum PSA level to the TRUS-estimated prostate volume.

RESULTS

The median PSA level was 4.4 ng/mL in patients with BPH, 9.3 ng/mL in patients with CaP-NO disease and 24 ng/mL in those with CaP-N+ disease. However, imposing a PSA limit of 4 ng/mL for the diagnosis of CaP gave a positive predictive value of only 64.8%, whereas a limit of 10 ng/mL gave a positive predictive value of 71.4%. In contrast, the median PSAD was 0.086 ng/mL/cm3 in patients with BPH, but was 0.295 ng/mL/cm3 in patients with NO-disease and 0.775 ng/mL/cm3 in those with N(+)-disease. With a limit of 0.15 ng/mL/cm3 the positive predictive value of PSAD was 81%. Furthermore, a limit of 0.6 ng/mL/cm3 revealed a positive predictive value of 81% for the diagnosis of metastatic lymph node involvement.

CONCLUSIONS

There was a considerable overlap of PSA concentrations in patients with BPH and CaP, and PSA was not sufficiently accurate to distinguish between them. In contrast, PSAD enhanced the discrimination between BPH and CaP and may provide additional information about the status of the lymph nodes in patients with CaP.

PSA and clinical problems relating to prostate cancer

The PSA is the most important tumoral marker for prostate cancer. Not all Authors agree that it plays an important role in screening and diagnosis, classification and prognosis; they agree, instead, about its monitoring the response to therapy. Two personal experiences are presented: in one the PSA values are compared with the prostatic biopsies in 100 patients with suspect rectal exploration; in the other the PSA value, taken at the moment of diagnosis, is compared with the result of the radionuclide bone scan in 43 patients with prostate cancer.

Citrate as an in vivo marker to discriminate prostate cancer from benign prostatic hyperplasia and normal prostate peripheral zone: detection via localized proton spectroscopy

OBJECTIVES

This study was designed to determine whether citrate levels detected by localized 1H spectroscopy could reliably discriminate regions of prostate adenocarcinoma from surrounding regions of normal peripheral zone and benign prostatic hyperplasia (BPH).

METHODS

In 28 patients and 5 volunteers stimulated echo proton spectroscopy was used in conjunction with endorectal surface coils to obtain water-suppressed 1H spectra from regions of normal prostate peripheral zone, BPH, and prostate cancer. 1H spectra from prostate cancer patients were correlated with pathologic areas identified on T2-weighted endorectal coil magnetic resonance (MR) images and histologic study of the step-sectioned gland after surgery.

RESULTS

The major finding of in vivo studies was consistently lower citrate levels in prostate cancer compared with BPH and normal prostate peripheral zone. This was reflected by significantly (P < 0.05) lower mean citrate/(creatine plus choline) peak area ratio observed for regions of cancer (0.67 +/- 0.17) compared with BPH (1.21 +/- 0.29) and normal peripheral zone (1.46 +/- 0.28). Moreover, there was no overlap of individual cancer and normal peripheral zone citrate ratios and no significant difference between citrate ratios in regions of normal peripheral zone in young volunteers (1.28 +/- 0.14) and age-matched patients (1.46 +/- 0.28). The observed alterations in vivo citrate levels were supported by citrate concentration data obtained from extracts of histologically proven samples of normal, benign, and malignant prostatic tissues removed at surgery. In vitro citrate levels in the normal peripheral zone (30.9 +/- 8.5 mumol/g wet weight) and BPH (46.3 +/- 5.4 mumol/g wet weight) were significantly higher than those for prostate cancer (3.74 +/- 0.54 mumol/g wet weight).

CONCLUSIONS

These studies further demonstrate the potential of citrate as an in vivo marker for discriminating prostate cancer from surrounding regions of normal peripheral zone and BPH.

Incidental carcinoma of the prostate

Transrectal ultrasonography (TRUS), digital rectal examination (DRE), and quantification of serum prostate-specific antigen (PSA) are accepted and evaluated methods for detecting prostate cancer. Positive predictive values (PPV) of DRE and TRUS are low, and only slightly enhanced when used in combination with PSA. PSA lacks sufficient sensitivity and specificity to be used alone as a screening test for prostate cancer. The parameters PSA-density and PSA-velocity make PSA a better tumor marker, but they are not reliable on an individual basis. Age-specific reference ranges have the potential to make PSA a more sensitive tumor marker for men less than 60 years of age and a more specific one for men beyond 60 years. With currently available diagnostic methods approximately 10% of patients undergoing transurethral or open resection of the prostate for presumed benign prostatic hyperplasia will have carcinoma detected in the histologic material. In 392 patients successively treated in our clinic for presumed BPH and thoroughly investigated to exclude prostatic carcinoma (DRE, TRUS, biopsy when PSA > 4 ng/ml or PSA-D > 0.15), the tumor was found incidentally in 4%. Another finding in this study was the detection of prostatic carcinoma by random biopsy in patients without a palpable or visible tumor by imaging and without PSA increase (> 4 ng/ml). Biopsies were performed because of a hypoechoic zone in the opposite lobe which turned out to be negative. Such tumors cannot be properly classified in the current TNM system. Treatment options for patients with incidental prostatic carcinoma are age- and stage-dependent. Patients less than 60 years old may be treated with a curative approach, irrespective of the T category (T1a or T1b); patients with a life expectancy longer than 10 years and a pT1b incidental carcinoma likewise should be offered a curative therapy.