Percentage of free prostate-specific antigen: implications in modern extended scheme prostate biopsy

Percentage of free prostate-specific antigen (PSA) is a useful method in deciding to perform prostate biopsy with higher core numbers in patients with low PSA cut-off values

The aim of this study was to evaluate the predictive role of percentage of free prostate-specific antigen (%fPSA) cut-points in prostate cancer (PCa) detection in patients with total PSA (tPSA) levels between 2.5 ng/mL and 10.0 ng/mL. In total, 1321 consecutive initial transrectal ultrasound (TRUS)-guided 12-core biopsies performed between 2005 and 2011 were evaluated retrospectively. Benign pathologies, high-grade prostatic intraepithelial neoplasia, and atypical small acinary proliferations were categorized as noncancerous (benign), and prostate adenocarcinomas were categorized as cancerous (malignant). The patients were categorized according to: Catalona's published %fPSA categories (<10%, 10-15%, 15-20%, 20-25%, or > 25%); digital rectal examination (DRE) results [benign (negative) or suspicious of malignancy (positive)]. There was a significant relationship between the %fPSA cut-points and detection of PCa in DRE-negative patients. The presence of a 10% cut-point increased the probability of PCa threefold. The %fPSA was significantly more related to PCa than the tPSA value in receiver operating characteristic (ROC) curve analyses (p = 0.001). Based on our findings, a lower %fPSA, especially <10%, is an important parameter when deciding whether to perform a biopsy on patients with a tPSA between 2.5 ng/mL and 10 ng/mL.

Effect of constipation on serum total prostate-specific antigen levels in men

OBJECTIVES

Many factors affecting serum prostate-specific antigen (PSA) levels have been described. The aim of this study was to examine the effect of constipation on serum PSA levels in men.

METHODS

Serum total PSA values were measured in 136 constipated patients before and after treatment for constipation. Moreover, they were compared with 45 control patients.

RESULTS

Serum total PSA values in the constipated patients before treatment were significantly higher than those in the control group (2.29 ± 1.29 ng/mL vs 1.28 ± 0.86 ng/mL, P < 0.0001). After the treatment of constipation, serum total PSA values in the constipated patients were still higher than those in the control group, but this difference was not statistically significant (P = 0.0871). After the treatment of constipation, prostate biopsy rates were 6.6% and 2.2% in the study and control group, respectively (P = 0.2769). No prostate cancer was found in both groups.

CONCLUSIONS

Constipation increases serum PSA levels in men. The presence of constipation must be considered in patients whose PSA is examined, especially in those with PSA levels that are borderline high or in the range of 2-10 ng/mL. Constipated patients must be first treated and then re-evaluated.

Utility of percent free prostate-specific antigen in repeat prostate biopsy

OBJECTIVES

To assess the utility of the percent free prostate-specific antigen (%fPSA) for the prediction of prostate cancer in men undergoing repeat biopsy.

METHODS

A retrospective review was performed of 1037 patients in an institutional review board-approved repeat prostate biopsy database. A total of 617 patients who underwent 683 biopsies had all their data available for analysis. The patients were categorized as having undergone 1 repeat biopsy or >1 repeat biopsy.

RESULTS

The overall cancer detection rate was 27% and 22% in men who underwent 1 and >1 repeat biopsy, respectively. The area under the receiver operating characteristic curve for the %fPSA was 0.65 for men who underwent 1 repeat biopsy. Multivariate analysis demonstrated that a positive family history, decreasing %fPSA, and presence of high-grade intraepithelial neoplasia and/or atypical small acinar proliferation predicted for cancer. The univariate odds ratio for every 5% decrease in the %fPSA was 1.5 (95% confidence interval 1.2-1.7). The performance of %fPSA was further improved in men who underwent >1 repeat biopsy, with an area under the curve of 0.72. In men who underwent >1 repeat biopsy, multivariate analysis showed that a decreasing %fPSA, >20 cores removed, and high-grade intraepithelial neoplasia predicted for cancer. The univariate odds ratio for every 5% decrease in the %fPSA was 1.8 (95% confidence interval 1.4-2.3). A %fPSA cutoff of 10% achieved 90% and 91% specificity in the 1 repeat biopsy and >1 repeat biopsy groups, respectively.

CONCLUSIONS

%fPSA is useful in predicting for prostate cancer in the repeat biopsy population, particularly for those who have undergone multiple repeat biopsies. A persistently low %fPSA should prompt additional investigation in these men.

Epigenetic regulation of prostate cancer

Prostate cancer is a commonly diagnosed cancer in men and a leading cause of cancer deaths. Whilst the underlying mechanisms leading to prostate cancer are still to be determined, it is evident that both genetic and epigenetic changes contribute to the development and progression of this disease. Epigenetic changes involving DNA hypo- and hypermethylation, altered histone modifications and more recently changes in microRNA expression have been detected at a range of genes associated with prostate cancer. Furthermore, there is evidence that particular epigenetic changes are associated with different stages of the disease. Whilst early detection can lead to effective treatment, and androgen deprivation therapy has a high response rate, many tumours develop towards hormone-refractory prostate cancer, for which there is no successful treatment. Reliable markers for early detection and more effective treatment strategies are, therefore, needed. Consequently, there is a considerable interest in the potential of epigenetic changes as markers or targets for therapy in prostate cancer. Epigenetic modifiers that demethylate DNA and inhibit histone deacetylases have recently been explored to reactivate silenced gene expression in cancer. However, further understanding of the mechanisms and the effects of chromatin modulation in prostate cancer are required. In this review, we examine the current literature on epigenetic changes associated with prostate cancer and discuss the potential use of epigenetic modifiers for treatment of this disease.