Comparison of methods for prediction of prostate cancer in Turkish men with PSA levels of 0-10 ng/mL

PURPOSE

Several concepts to improve the diagnostic accuracy of prostate specific antigen (PSA) for prediction of prostate cancer have been studied. The aim of this study was to examine and compare the methods used for improving the diagnostic accuracy of PSA in a country with low incidence of prostate cancer.

METHODS

997 patients with prostate biopsy were included into study. Predictive models using PSA, PSA density (PSAD), free PSA/total PSA (f/tPSA), binary logistic regression (LR) analysis, artificial neural networks (ANNs), and decision trees (DTs) have been developed. For LR, ANNs and DTs, a validation group consisting of 241 cases was reserved.

RESULTS

193 (19%) biopsies out of 997 showed prostatic cancer. Median PSAD in patients with malignant and benign lesions were 0.21 and 0.16, respectively (p<0.001). According to 25% f/tPSA cut-off level, 18.4% of the patients with PSA<25% and 16.0% of the patients with PSA>25% had prostate cancer (p=0.423). Receiver operating characteristics (ROC) area under the curve (AUC) values for PSA, PSA density, f/tPSA, LR, ANNs, and DTs were 0.587, 0.625, 0.560, 0.678, 0.644, and 0.698, respectively. ROC AUCs in the validation group for LR, ANNs and DTs were 0.717, 0.516 and 0.629 respectively.

CONCLUSIONS

For cases with f/tPSA<25%, no increased probability for prostatic carcinoma was observed. Multivariate models have higher AUCs than PSA, PSAD or f/tPSA. LR, DTs and ANNs showed similar results, however application of ANNs to the validation group produced a significantly lower AUC, limiting the value of ANNs in this situation.

Relationship between mast cell and iNOS expression in testicular tissue associated with infertility

The objective of this study was to investigate mast cells and iNOS expression in testis tissue, and to correlate these results with spermatogenic disorders. A total of 136 testicular biopsies were obtained from the testes of 80 patients with infertility. Their age ranged from 21 to 45 years. The biopsy specimens were immunohistochemically stained with antihuman tryptase for mast cells. In each section, all interstitial fields were evaluated for the total number of mast cells as well as the total number of Leydig cells. The number of mast cells per Leydig cell was calculated and recorded as mast cell index. Immunohistochemical iNOS staining was evaluated semiquantitatively according to intensity and the proportion of the stained cells. There was a significant increase of the mast cell index in all groups with testicular disorder compared with normal spermatogenesis group (p < 0.05). Increase of the index was in the order of hypospermatogenesis, maturation arrest and SCO, and index of SCO group was especially higher, i.e, more than twice than other groups. iNOS score was significantly higher in the SCO group than in the men with normal spermatogenesis, hypospermatogenesis, and maturation arrest (p < 0.05). Finally, a significantly statistical correlation was found between the iNOS score and mast cells index (r = 0.758, p = 0.001). Increase of mast cell index was observed in the groups of infertile testis, and high expression of iNOS in Leydig cells was associated with the highest mast cell index in SCO, the lesion with the most severe damage of the germ cell.