Need For Prostate Biopsy Research Articles

Novel Artificial Neural Network for Early Detection of Prostate Cancer

PURPOSE: Two artificial neural networks (ANN) for the early detection of prostate cancer in men with total prostate-specific antigen (PSA) levels from 2.5 to 4 ng/mL and from 4 to 10 ng/mL were prospectively developed. The predictive accuracy of the ANN was compared with that obtained by use of conventional statistical analysis of standard PSA parameters. PATIENTS AND METHODS: Consecutive men with a serum total PSA level between 4 and 10 ng/mL (n = 974) and between 2.5 and 4 ng/mL (n = 272) were analyzed. A separate ANN model was developed for each group of patients. Analyses were performed to determine the presence of prostate cancer. RESULTS: The area under the receiver operator characteristic (ROC) curve (AUC) was 87.6% and 91.3% for the 2.5 to 4 ng/mL and 4 to 10 ng/mL ANN models, respectively. For the latter model, the AUC generated by the ANN was significantly higher than that produced by the single variables of total PSA, percentage of free PSA, PSA density of the transition zone (TZ), and TZ volume (P < .01), but not significantly higher compared with multivariate analysis. For the 2.5 to 4 ng/mL model, the AUC of the ANN ROC curve was significantly higher than the AUCs for percentage of free PSA (P = .0239), PSA-TZ (P = .0204), and PSA density and total prostate volume (P < .01 for both). CONCLUSION: The predictive accuracy of the ANN was superior to that of conventional PSA parameters. ANN models might change the way patients referred for early prostate cancer detection are counseled regarding the need for prostate biopsy.

Utilidad de la ecografía transrectal con Doppler color en el diagnóstico del cancer de próstata. Estudio de 101 casos

ObjectiveTo determine the value of color Doppler ultrasound in the detection of prostate cancer. To relate asymmetries in vascularization with the results of directed biopsy. Patients and methodsBetween May and November 2000, we studied 101 patients suspected of having prostate cancer. The selection criteria were a prostate-specific antigen level of over 3 ng/ml, suspicious digital rectal examination or both.The volume, capsule and internal architecture were assessed, focusing on nodules, suspicious hypoechoic areas and asymmetric color intensity.Sextant biopsies were carried out with an 18-gauge needle and samples were also taken of the areas of increased color intensity. ResultsThe mean patient age was 64.1 ± 7.89 years. Cancer was detected in 25 patients (24.8%): 22 cases of adenocarcinoma (21.8%) and 3 cases of intraepithelial neoplasia (PIN). In 48 patients (47.5%), the diagnosis was benign hyperplasia and 26 (25.7%) presented chronic prostatitis. Two patients were diagnosed as having glandular atrophy.Digital rectal examination was suspicious in 26 cases and was considered normal in the remaining 75. The presence of malignant lesions was confirmed in 14 of the former 26 patients, for a sensitivity of 53.9%, a specificity of 85.9%, a positive predictive value of 53.9% and a negative predictive value of 85.9%.Transrectal ultrasound (TRUS) was described as suggestive of benignity in 34 patients, 5 of whom presented carcinomas. The study revealed some anomaly suggestive of malignancy in 67 cases; carcinomas were discovered i 20 of them (p = 0.9). Thus, in our series, TRUS showed a sensitivity of 80%, a specificity of 38.2%, a positive predictive value of 29.9% and a negative predictive value of 85.3%.Fifty-three patients presented asymmetries in color intensity. In this group, biopsy revealed 14 cases of adenocarcinoma, 1 case of highgrade PIN, 27 cases of benign hypertrophy and 11 of chronic prostatitis.Asymmetry was observed in 15 of the 25 cases of cancer. 13 hypervascular and 2 hypovascular lesions. Vascular asymmetries were not detected in the remaining 10 patients. ConclusionsColor Doppler ultrasound does not obviate the need for prostate biopsy in patients suspected of having cancer. It can be of aid by revealing suspicious areas for biopsy.A color Doppler signal of increrased intensity is not definitive in the diagnosis of cancer. In our study, prostate cancer was associated with increased vascular flow in 52% of cases.Since in cases of confirmed neoplasia, an increase in vascularization was associated with a higher Gleason score, we recommend that biopsy specimens be obtained from areas i which the signal is most intense to determine the highest Gleaseon score.

Probability of prostate cancer detection based on results of a multicenter study using the AxSYM free PSA and total PSA assays

Objectives. The determination of the percentage of free prostate-specific antigen (%fPSA) enhances the specificity of prostate cancer (CaP) detection. This study was undertaken to assess the performance of %fPSA in differentiating benign prostate disease from CaP and to determine the CaP probability estimates using the AxSYM Free PSA and AxSYM Total PSA assays. Methods. In this prospective study, 297 men, 50 years old or older, with a total PSA level between 4 and 10 ng/mL and a nonsuspicious digital rectal examination were enrolled at 10 clinical sites. All subjects underwent at least sextant prostate biopsies to establish the diagnosis. fPSA and total PSA (tPSA) levels were determined using the AxSYM Free PSA and AxSYM Total PSA assays. Percent fPSA values were compared with tPSA values to determine the appropriate cutoffs for prostate biopsy and to calculate the CaP probability estimates. Results. The strongest predictor of CaP in a logistic regression model was %fPSA (odds ratio 2.29), which contributed significantly more than age or tPSA to the predictive model. In this study population, a %fPSA cutoff of 26.4% would have detected 96% of subjects with CaP (sensitivity) and would have eliminated 27.4% of unnecessary biopsies (specificity). CaP probability estimates ranged from 9% to 69% and increased as the %fPSA value decreased. Men with a %fPSA level of 10% or lower had a 69% probability of CaP, and men with a %fPSA level of greater than 26% had a 9% probability of CaP. Conclusions. Percent fPSA values can help differentiate CaP from benign prostate disease and reduce unnecessary biopsies in 27% of men 50 years old or older whose digital rectal examination was normal and whose tPSA level was between 4 and 10 ng/mL. A %fPSA result can assist the physician and patient in determining the probability of CaP and assessing the need for prostate biopsy.

Analytical and Clinical Performance Characteristics of Hybritech’s Tandem-R free PSA Assay during a Large Multicenter Clinical Trial to Determine the Clinical Utility of Percentage of Free Prostate-specific Antigen

Prostate-specific antigen (PSA) is present in serum in several forms, most importantly free PSA (FPSA) and PSA complexed to α1-antichymotrypsin (1)(2). These PSA forms are useful in assessing prostate disease (3)(4)(5). When PSA is >10 μg/L (ng/mL), the probability of prostate cancer is 50% (6); when PSA is between 4 and 10 μg/L, the probability of prostate cancer is 25%. Patients in the latter range are usually recommended for biopsy, but here the low specificity leads to many unnecessary biopsies. The percentage of FPSA (%FPSA) is used to enhance specificity. The relative proportion of FPSA in serum may range from 5% to 50% (7), but a lower %FPSA is associated with higher probability of prostate cancer (8). Published guidelines for the clinical use of %FPSA have been contradictory because of differences in assay systems and standardization, study designs, patient populations, and the number of subjects enrolled (9). A large well-controlled multicenter clinical trial was conducted to define a medically significant %FPSA cutpoint that would indicate the need for prostate biopsy. This report summarizes the assay performance from the largest clinical trial to date evaluating %FPSA in a patient population representative of those men in whom the test would be used in clinical practice. The data formed the basis for the Food and Drug Administration’s approval of Hybritech’s free PSA assays. Detailed clinical performance characteristics have been presented previously (10). The objective of this clinical trial was twofold: to evaluate the performance of Hybritech’s Tandem®-R free PSA assay as it is routinely used in laboratories, and to identify a %FPSA cutpoint with a high rate of cancer detection (clinical sensitivity) while avoiding unnecessary biopsies in men without …

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 ≤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.

AGE SPECIFIC PROSTATE SPECIFIC ANTIGEN REFERENCE RANGES: POPULATION SPECIFIC

Purpose We determined whether 60 to 79-year-old men with a negative digital rectal examination and a serum prostate specific antigen (PSA) within age specific PSA reference ranges could safely forgo prostate biopsy. Materials and Methods We reviewed the medical records of all 60 to 79-year-old men at the Brooklyn Veterans Administration Medical Center who had a PSA assay, digital rectal examination and subsequent prostate biopsy for an abnormal rectal examination and/or PSA greater than 4.0 ng./ml. from January 1991 through August 1995. We compared our results using the standard reference range of 0 to 4.0 ng./ml. with those obtained had we used any of 4 different age specific PSA reference ranges. Results We performed 1,280 prostate biopsies in 1,046 men with available PSA and digital rectal examination data. Using age specific PSA reference ranges 73 of 1,280 biopsies (5.7%) would have been avoided. Of those 73 avoided biopsies 15 (20.5%) had cancer that would have gone undetected and 9 of 15 (60%) undetected cancers had unfavorable histology. Results were not statistically significantly different among the 4 age specific PSA reference ranges. Regarding race, cancer detection rates were significantly higher for black compared with white men but there was no statistically significant difference for missed cancers or missed cancers with unfavorable histology. Conclusions In contrast to previous reports of unfavorable histological characteristics in only 5% of missed cancers using age specific PSA reference ranges, 60% of missed cancers in our patients exhibited unfavorable histology. We conclude that age specific PSA reference ranges did not safely eliminate the need for prostate biopsy in our study population. In 60 to 79-year-old men with a negative digital rectal examination we continue to use PSA greater than 4.0 ng./ml. as an indication for prostate biopsy.

Prospective Evaluation of Prostate Specific Antigen and Prostate Specific Antigen Density in the Detection of Carcinoma of the Prostate: Ethnic Variations

We evaluated prospectively the ethnic variations in prostate specific antigen (PSA) and prostate specific antigen density in the detection of carcinoma of the prostate. A total of 297 consecutive patients with an elevated serum PSA and/or abnormal digital rectal examination underwent transrectal ultrasound with lesion directed and systematic biopsy (6 if the prostatic volume was 50 cc or less and 12 if it was greater than 50 cc). Receiver operating characteristic curves, predictive values and likelihood ratios were calculated for PSA and PSA density for white and black patients. Ethnic analysis was performed for the entire group, patients with a normal digital rectal examination, and those with a normal digital rectal examination and PSA of 4 to 10 ng./ml. Of the 297 patients 131 (44%) had cancer, including 48 of 97 black (50%) and 83 of 200 white (42%) patients. Median PSA, PSA density and prostate size did not differ between the positive or negative biopsy groups, or between the ethnic groups in any of the analyses. If all digital rectal examinations were considered PSA density was superior to PSA by receiver operating characteristic analysis for cancer detection in both ethnic groups when all values or PSA of 4 to 10 ng./ml. were considered. However, the significance was lost if only patients with a normal digital rectal examination were considered. In general, predictive values were greater in black patients. Likelihood ratios for a negative test result in black patients demonstrated significant changes in the post-test probability if a PSA density cutoff of 0.1 was used to determine the need for biopsy. Many unnecessary biopsies could be avoided and few cancers would be missed. A PSA density cutoff of 0.1 may be warranted in determining the need for prostate biopsy in black men with a normal digital rectal examination.