18F-PSMA-1007 PET/CT Performance on Risk Stratification Discrimination and Distant Metastases Prediction in Newly Diagnosed Prostate Cancer

Objective

To evaluate the prediction performance of ¹⁸F-PSMA-1007 PET/CT and clinicopathologic characteristics on prostate cancer (PCa) risk stratification and distant metastatic prediction.

Materials and Methods

A retrospective analysis was performed on 101 consecutively patients with biopsy or radical prostatectomy proved PCa who underwent ¹⁸F-PSMA-1007 PET/CT. The semi-quantitative analysis provided minimum, maximum and mean standardized uptake (SUVmin, SUVmax and SUVmean) of PCa. Association between clinicopathologic characteristics (total prostate-specific antigen, tPSA and Gleason Score, GS) and PET/CT indexes were analyzed. The diagnostic performance of distant metastatic on PET/CT parameters, tPSA and GS was evaluated using logistic regression analyses. A path analysis was conducted to evaluate the mediating effect of tPSA level on the relation between semi-quantitative parameters of primary tumors and metastatic lesions.

Results

The PET/CT parameters were all higher in high risk stratification subgroups (tPSA>20 ng/mL, GS ≥ 8, and tPSA>20 ng/mL and/or GS ≥ 8, respectively) with high sensitivity (86.89%, 90.16% and 83.61%, respectively). The SUVmax, tPSA and GS could effectively predict distant metastatic with high sensitivity of SUVmax (90.50%) compared with tPSA (57.14%) and GS (55.61%). With a cutoff value of 29.01ng/mL for tPSA, the detection rate of distant metastasis between low and high prediction tPSA group had statistical differences (50.00% vs. 76.60%, respectively; P = 0.006) which was not found on guideline tPSA level (P>0.05). 6/15 (40%) patients tPSA between 20ng/mL to 29.01ng/mL without distant metastases may change the risk stratification. Finally, tPSA had a partial mediating effect on SUVmax of primary tumors and metastases lesions.

Conclusion

The ¹⁸F-PSMA-1007 PET/CT SUVmax has a higher sensitivity and can be an “imaging biomarker” for primary PCa risk stratification. The prediction tPSA level (29.01 ng/mL) is more conducive to the assessment of distant metastasis and avoid unnecessary biopsy.

Effect of prostate volume on f/tPSA value: A cross-sectional study

Previous studies have suggested that there is a positive correlation between prostate-specific antigen (PSA) levels and prostate volume (PV). A better understanding of the possible influence of PV on a ratio of free to total PSA (f/tPSA) may improve the diagnostic value of the prostate disease. The study group consisted of 342 men with lower urinary tract symptoms (LUTS). All patients underwent urinary tract ultrasonography and had tests carried out on PSA, serum glucose, total cholesterol, triglyceride, HDL, LDL and blood pressure. Univariate and multivariate analyses were used to assess the associations between prostate volume and f/tPSA value. We found no obvious relationship between prostate volume and f/tPSA value when PSA >10 ng/ml but did observe a positive correlation when 4 ng/ml < PSA ＜ 10 ng/ml (hazard ratio [HR]: 0.0012; 95% confidence interval [CI]: 0.0009-0.0248). With increasing prostate volume, multivariate analysis showed an obvious increase in f/tPSA value (HR: 0.0011; 95% CI: 0.0007-0.0015) (p ≤ .0001). We confirmed that prostate volume could affect the f/tPSA levels in serum. There was an obvious positive correlation between prostate volume and f/tPSA level when PSA levels were between 4 and 10ng/dl. There was no significant correlation between prostate volume and f/tPSA value when PSA >10 ng/ml.

Establishing a prediction model for prostate cancer bone metastasis

We collected clinical data from 308 prostate cancer (PCa) patients to investigate the clinical characteristics and independent risk factors of bone metastasis (BM) and to establish a prediction model for BM of PCa and determine the necessity of bone scans. Univariate and multivariate analyses were performed based on age, biopsy Gleason score (BGS), clinical tumor stage (cTx), total prostate specific antigen (tPSA), free prostate specific antigen (fPSA), fPSA/tPSA, prostate volume, alkaline phosphatase (ALP), serum calcium and serum phosphorus. Moreover, 80 of the 308 PCa patients had a PI-RADS v2 score and were analysed retrospectively. The univariate analysis showed that the BGS, cTx, tPSA, fPSA, prostate volume and ALP were significant. The multivariate logistic regression analysis showed significant differences among the BGS, cTx, tPSA and ALP. Four cases should be highly suspected with BM: (i) cTl-cT2, BGS ≤7, ALP >120 U/L and tPSA >90.64 ng/ml; (ii) cTl-cT2, BGS ≥8, and ALP >120 U/L; (iii) cT3-cT4, BGS ≤7, and ALP >120 U/L; and (iv) cT3-cT4 and BGS ≥8. After the PI-RADS v2 score was included in the model, the AUC of the prediction model rose from 0.884 (95% CI: 0.813-0.996) to 0.934 (95% CI: 0.883-0.986). This model may help determine the necessity of bone scans to diagnose BM for PCa patients.

Elevated prostate specific antigen and reduced 10-year survival among a cohort of Danish men consecutively referred from primary care to an urological department during 2005-2006

It remains unclear whether total prostate specific antigen (tPSA) or complex PSA (cPSA) has the best diagnostic performance. Additionally, the utility of percentage free PSA (%fPSA) is still debated. Our objectives were to compare the diagnostic performances of tPSA, cPSA, and %fPSA among patients referred from GP to an Urological Specialist and to investigate prognostic factors and survival in the cohort. A total of 1261 consecutive male patients without previously known prostate cancer (PCa) were referred to the same Department of Urology during June 2005 to August 2006. Some 299 patients were diagnosed with PCa and 962 patients were found without PCa. Among the PCa patients, the median age, tPSA, cPSA, and %fPSA levels were 70.8 years, 13.4 μg/L, 10.8 μg/L, and 12.6%. For patients without PCa the results were 67.5 years, 2.5 μg/L, 1.9 μg/L, and 24.9%. The sensitivity, specificity, PVpos, PVneg, and efficiency of tPSA and cPSA were overlapping (p > .05). In the tPSA interval >4 μg/L - ≤20 μg/L, %fPSA excluded PCa with a PVneg of 72.4%; 38.5% of PCa patients had a tPSA concentration >20 μg/L at the time of referral and these patients had a reduced 10-year survival as compared to patients with tPSA concentrations ≤20 μg/L. In conclusion, tPSA and cPSA showed similar diagnostic performances. %fPSA provided additional diagnostic information at tPSA concentrations >4 μg - ≤20 μg/L. The high percentage of patients with tPSA concentrations >20 μg/L indicate delayed use of tPSA resulting in advanced disease at presentation and reduced patient survival.

Early Prediction of Therapy Response to Abiraterone Acetate Using PSA Subforms in Patients with Castration Resistant Prostate Cancer

The purpose of this study was to evaluate the prognostic ability of early changes of total prostate specific antigen (tPSA), free PSA (fPSA), [−2]proPSA and the Prostate Health Index (PHI) following initiation of Abiraterone-therapy in men with castration resistant prostate cancer (mCRPC). In 25 patients, PSA-subforms were analyzed before and at 8–12 weeks under therapy as prognosticators of progression-free-survival (PFS) and overall survival (OS). Comparing patients with a PFS < vs. ≥12 months by using Mann–Whitney–Wilcoxon Tests, the relative-median-change of tPSA (−0.1% vs. −86.8%; p = 0.02), fPSA (12.1% vs. −55.3%; p = 0.03) and [−2]proPSA (8.1% vs. −59.3%; p = 0.05) differed significantly. For men with ≤ vs. >15 months of OS there was a non-significant trend for a difference in the relative-median-change of fPSA (17.0% vs. −46.3%; p = 0.06). In Kaplan–Meier analyses, declining fPSA and [−2]proPSA were associated with a longer median PFS (13 months, 95% confidence interval (CI): 9.6–16.4 vs. 10 months, 95% CI: 3.5–16.5; p = 0.11), respectively. Correspondingly, decreasing fPSA and [−2]proPSA values indicated an OS of 32 months (95% CI: not reached (NR)) compared to 21 months in men with rising values (95% CI: 7.7–34.3; p = 0.14), respectively. We concluded that the addition of fPSA- and [−2]proPSA-changes to tPSA-information might be further studied as potential markers of early Abiraterone response in mCRPC patients.

Analytical performance of the VITROS® Immunodiagnostic Products total PSA II and free PSA assays

OBJECTIVES

To assess the precision and the performance of the VITROS(®) total PSA II (tPSA) and free PSA (fPSA) assays on the VITROS(®) ECi/ECiQ Immunodiagnostic system.

DESIGN AND METHODS

The precision of the tPSA and fPSA assays was evaluated following the Clinical and Laboratory Standards Institute (CLSI)-guideline EP5-A2. During a 20-day period, 2 runs of 5 quality control (QC) samples were performed daily. Results of tPSA (n=292) and fPSA (n=289) were compared between VITROS(®) ECi/ECiQ Immunodiagnostic system and Roche Cobas 8000 e602 system (Cobas tPSA and fPSA assays). A modified CLSI-guideline EP9-A2 was used to correlate the results based on a Deming regression correlation study.

RESULTS

A within-run and within-calibration imprecision of ≤2% was obtained for all 5 QC concentration levels for both tPSA and fPSA. Method comparison revealed a constant bias of 17% for tPSA and 6% for fPSA. These values are within the desirable bias of 18.7% suggested by the Westgard Biological Variation Database Specifications. A high agreement was found between the two methods, with correlation coefficients of 0.997 and 0.993 for tPSA and fPSA respectively.

CONCLUSION

The VITROS(®) tPSA and fPSA assays showed an excellent precision and bias and a good correlation with the Roche method.

Comparative effectiveness review: prostate cancer antigen 3 testing for the diagnosis and management of prostate cancer

PURPOSE

We compared the effectiveness of PCA3 (prostate cancer antigen 3) and select comparators for improving initial or repeat biopsy decision making in men at risk for prostate cancer, or treatment choices in men with prostate cancer.

MATERIALS AND METHODS

MEDLINE®, EMBASE®, Cochrane Database and gray literature were searched from January 1990 through May 2012. Included studies were matched, and measured PCA3 and comparator(s) within a cohort. No matched analyses were possible. Differences in independent performance estimates between PCA3 and comparators were computed within studies. Studies were assessed for quality using QUADAS (Quality Assessment of Diagnostic Accuracy Studies) and for strength of evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria.

RESULTS

Among 1,556 publications identified, 34 observational studies were analyzed (24 addressed diagnostic accuracy and 13 addressed treatment decisions). Most studies were conducted in opportunistic cohorts of men referred for procedures and were not designed to answer key questions. Two study biases (partial verification and sampling) were addressed by analyses, allowing some conclusions to be drawn. PCA3 was more discriminatory than total prostate specific antigen increases (eg at an observed 50% specificity, summary sensitivities were 77% and 57%, respectively). Analyses indicated that this finding holds for initial and repeat biopsies, and that the markers were independent predictors. For all other biopsy decision making comparisons and associated health outcomes, strength of evidence was insufficient. For treatment decision making, strength of evidence was insufficient for all outcomes and comparators.

CONCLUSIONS

PCA3 had a higher diagnostic accuracy than total prostate specific antigen increases, but strength of evidence was low (limited confidence in effect estimates). Strength of evidence was insufficient to conclude that PCA3 testing leads to improved health outcomes. For all other outcomes and comparators, strength of evidence was insufficient.

SRD5A1 and SRD5A2 are associated with treatment for benign prostatic hyperplasia with the combination of 5α-reductase inhibitors and α-adrenergic receptor antagonists

PURPOSE

Common treatments for benign prostatic hyperplasia include 5α-reductase inhibitors and α-adrenergic receptor antagonists. However, these treatments can only partially decrease the risk of benign prostatic hyperplasia progression. SRD5A1 and SRD5A2 are 5α-reductase inhibitor targets. We investigated the association between drug efficacy and single nucleotide polymorphisms in the SRD5A1 and SRD5A2 genes in a Chinese population.

MATERIALS AND METHODS

We genotyped 11 tagging single nucleotide polymorphisms in the SRD5A1 and SRD5A2 genes in a total of 426 benign prostatic hyperplasia cases and 1,008 controls from Xinhua Hospital, Shanghai, People's Republic of China. Cases were treated with type II 5α-reductase inhibitors and α-adrenergic receptor antagonists. We tested the association of tagging single nucleotide polymorphisms with benign prostatic hyperplasia risk/progression, clinical characteristics at baseline, including the I-PSS (International Prostate Symptom Score) and total prostate volume, and changes in clinical characteristics after treatment.

RESULTS

The 11 tagging single nucleotide polymorphisms were not significantly associated with benign prostatic hyperplasia risk or progression (each p >0.05). In the SRD5A1 gene rs6884552 and rs3797177 were significantly associated with baseline I-PSS (p = 0.04 and 0.003, respectively). In the SRD5A2 gene rs523349 (V89L) and rs9332975 were significantly associated with baseline total prostate volume (p = 0.01 and 0.001, respectively). In SRD5A1 rs166050 was significantly associated with the posttreatment change in total prostate volume (p = 0.04). In SRD5A2 rs523349 and rs612224 were significantly associated with the posttreatment I-PSS change (p = 0.03 and 0.009, respectively).

CONCLUSIONS

SRD5A1 and SRD5A2 single nucleotide polymorphisms are significantly associated with the clinical characteristics of benign prostatic hyperplasia and the efficacy of benign prostatic hyperplasia treatment.

Can mean platelet volume serve as a marker for prostatitis?

AIM

The aim of the study was to compare the yield of mean platelet volume (MPV), total prostate specific antigen (tPSA), free prostate specific antigen (fPSA), f/t PSA ratio and complex prostate specific antigen (cPSA) in patients with prostatitis.

MATERIAL AND METHOD

The study was designed in the Kayseri Education and Research Hospital. Ninety-six patients with prostatitis were enrolled retrospectively into the study. Laboratory data were obtained from the computerized patient database. We evaluated the correlation between tPSA, fPSa, f/t PSA ratio, cPSA, MPV and extent and aggressiveness of inflammation in the surgical specimens of patients who underwent surgery for benign prostatic hyperplasia (BPH). Inflammation in the prostatic tissues was scored for extent and aggressivity of inflammation using the grading system designed by Irani et al.

RESULTS

The total PSA, fPSa, f/t PSA ratio, cPSA and pre- and post-treatment MPV values of each group did not differ (p>0.05) (Table 1). Also there was no correlation between the histopathological grades and the MPV, tPSA, fPSA, f/t PSA ratio and cPSA of patients. However, MPV values significantly decreased after treatment in all grades of prostatitis (p<0.001).

CONCLUSION

MPV values may be used as an inflammation marker in patients with prostatitis.

Preventing Unnecessary Invasive Cancer-Diagnostic Tests: Changing the Cut-off Points

BACKGROUND

To determine a cut-off point of tPSA and PSAD to prevent unnecessary invasive cancer-diagnosing tests in the community.

METHODS

This study was performed on 688 consecutive patients referred to our center due to prostatism, suspicious lesions on digital rectal examination and/or elevated serum PSA levels. All patients underwent transrectal ultrasound guided biopsies and obtained PSAD. Serum levels of tPSA and fPSA were measured by chemiluminescence. Comparisons were done using tests of accuracy (AUC-ROC).

RESULTS

Prostate cancer was detected in 334 patients, whereas the other 354 patients were suffering from benign prostate diseases. The mean tPSA in case and control groups were 28.32±63.62 ng/ml and 7.14±10.04 ng/ml; the mean f/tPSA ratios were 0.13± 0.21 and 0.26±0.24 in PCa and benign prostate disease groups; the mean PSAD rates were 0.69±2.24, 0.12±0.11, respectively. Statistically significant differences were found (P <0.05). Using ROC curve analysis, it was revealed that AUC was 0.78 for tPSA and 0.80 for f/tPSA. Sensitivity was 71% for the cut-off value of 7.85ng/ml. For f/tPSA ratio, the optimal cut-off value was 0.13 which produced the sensitivity of 81.4% and for PSAD, it was15%.

CONCLUSIONS

As this trial is different from the European and American values, we should be more cautious in dealing with the prostate cancer upon the obtained sensitivity and specificity for PCa diagnosis (7.85ng/mL for tPSA, 15% for PSAD and 0.13 for f/tPSA ratio).