Serum Prostate Specific Antigen Ratio Research Articles

Assessment the Ability of Free/Total Ratio of Serum PSA in Diagnosing Prostate Cancer and Benign Prostatic Hyperplasia

Background: The Prostate gland is the male secondary sexual organ most commonly affected by benign or malignant neoplasm. Prostate cancer (Ca-P) is one of the most commonly diagnosed cancers in men and is now the third commonest cause of cancer death in western countries.The aim of the study was to evaluate the use of serum prostate-specific antigen levels in differentiating prostate cancer from benign prostatic hyperplasia. Methods:The present study is a cross-sectional observational study.The study was conducted at the outpatient department and indoor patients at the department of Urology, Rajshahi Medical College Hospital (RMCH), Rajshahi, and different private clinic in Rajshahi City during the period from July 2019 to June 2020.The study population included male patients above 50 years of age, who attended in the department of Urology, Rajshahi Medical College Hospital (RMCH), Rajshahi, and different private clinic in Rajshahi City complaining of irritative or obstructive lower urinary tract symptoms (LUTS) suspected as clinically prostate cancer or benign prostatic hyperplasia (BPHStatistical analysis of the results was obtained by using window-based computer software devised with Statistical Packages for Social Sciences (SPSS-24). Results: The age distribution of the prostatic carcinoma and BPH patients. Prostatic carcinoma was observed to be significantly higher from 80 years onwards, while BPH was common between 60 - 80 years (p = 0.00001). Table 10shows the validity or accuracy of the free/total ratio of serum PSA as a diagnostic test in differentiating prostatic carcinoma from BPH in patientswith total PSA levels between 4-10ng/ml. The percentage of false positives was significantly higher when total PSA ratio was used to diagnose the disease compared to when free to total PSA was used as a diagnostic tool (p<0.000001). The overall accuracy of total PSA was also significantly lower (61.45%) than that of free/total PSA (91.67%) (p< 0.011526). Conclusion: Free and total prostate specific antigen (PSA) is increased significantly in carcinoma prostate than benign prostatic hyperplasia but free/total ratio of serum prostate- specific antigen level significantly decreases in prostatic carcinoma than benign prostatic hyperplasia. TAJ 2023; 36: No-2: 215-230

Serum biomarkers of inflammation for diagnosis of prostate cancer in patients with nonspecific elevations of serum prostate specific antigen levels

Background: Lactate dehydrogenase (LDH) and C-reactive protein (CRP) are biomarkers of inflammation commonly used in medicine. The aim was to evaluate the utility of serum LDH and CRP levels for diagnosis of prostate cancer (PC) in men with nonspecific elevations of serum total prostate specific antigen (PSA) levels. Methods: The following serum biomarkers were measured in patients with PSA between 4 and 10 ng/mL: LDH, CRP and free-PSA. The free-to-total serum PSA ratio (%fPSA) was (free-PSA/PSA) ×100. Patients were classified into two groups according to diagnosis of prostate biopsy: PC and NOT PC patients. Logistic regression was used for develop a probabilistic model to predict PC patients. Diagnostic accuracy was determined using receiver operating characteristic (ROC) curves, calculating the area under the ROC curve (AUC). Results: We studied 232 patients with ages between 43 and 98 years old (median =72), 200 NOT PC and 32 PC patients. CRP was not statistically significantl to differentiate between PC and NOT PC patients. Probabilistic model (%) was 100× (1+ e −Z ) −1 ; (Z =0.0070× LDH –0.1589× %fPSA –1.4898). The AUCs were 0.657 (P=0.0048), 0.802 (P<0.0001), and 0.844 (P<0.0001) for serum LDH levels, %fPSA values and probabilistic model, respectively. Conclusions: CRP was not useful to differentiate benign from malignant prostate disease, in contrast LDH could be used for diagnosis of PC. A probabilistic model using LDH and %fPSA can improve the diagnostic accuracy in patients with PSA between 4 and 10 ng/mL.

Serum biomarkers of inflammation for diagnosis of prostate cancer in patients with nonspecific elevations of serum prostate specific antigen levels.

BackgroundLactate dehydrogenase (LDH) and C-reactive protein (CRP) are biomarkers of inflammation commonly used in medicine. The aim was to evaluate the utility of serum LDH and CRP levels for diagnosis of prostate cancer (PC) in men with nonspecific elevations of serum total prostate specific antigen (PSA) levels.MethodsThe following serum biomarkers were measured in patients with PSA between 4 and 10 ng/mL: LDH, CRP and free-PSA. The free-to-total serum PSA ratio (%fPSA) was (free-PSA/PSA) ×100. Patients were classified into two groups according to diagnosis of prostate biopsy: PC and NOT PC patients. Logistic regression was used for develop a probabilistic model to predict PC patients. Diagnostic accuracy was determined using receiver operating characteristic (ROC) curves, calculating the area under the ROC curve (AUC).ResultsWe studied 232 patients with ages between 43 and 98 years old (median =72), 200 NOT PC and 32 PC patients. CRP was not statistically significantl to differentiate between PC and NOT PC patients. Probabilistic model (%) was 100× (1+ e−Z)−1; (Z =0.0070× LDH –0.1589× %fPSA –1.4898). The AUCs were 0.657 (P=0.0048), 0.802 (P<0.0001), and 0.844 (P<0.0001) for serum LDH levels, %fPSA values and probabilistic model, respectively.ConclusionsCRP was not useful to differentiate benign from malignant prostate disease, in contrast LDH could be used for diagnosis of PC. A probabilistic model using LDH and %fPSA can improve the diagnostic accuracy in patients with PSA between 4 and 10 ng/mL.

Free/Total Serum Prostate-Specific Antigen Ratio in Women with Colorectal Cancer Has Prognostic Significance.

The presence of prostate-specific antigen (PSA) in colon cancer tissues has been shown, but its clinical significance has not been known yet in colorectal cancer patients. We investigated the prognostic significance of percent free PSA value (free PSA/total PSA×100) in female patients with colorectal cancer. The serum concentrations of total and free PSA were measured by solid-phase two-site immunoradiometric assay in 184 patients. The cancer-specific survival (CSS) of patients with percent free PSA value ≥35 was significantly better compared to that of patients with percent free PSA value <35 (CSS rate was 82.9 and 55.5%, respectively; log-rank x2=8135, p=0.004). In multivariate Cox analysis, this percent free PSA threshold value had independent prognostic significance (relative risk 0.27, 95% confidence interval 0.11-0.64, p=0.003). Percent free PSA value, calculated by serum total and free PSA levels, has prognostic significance in women with colorectal cancer. The studies with larger patient series, utilizing ultrasensitive PSA assays whose lowest detection limit is lower, are required for a clearer understanding of this issue.

Serum lactate dehydrogenase in combination with free-to-total serum prostate specific antigen ratio for diagnosis of prostate cancer.

Evaluate the utility of serum lactate dehydrogenase (LDH) in combination with free-to-total serum prostate specific antigen ratio (%fPSA), for diagnosis of prostate cancer (PC) with serum total prostate specific antigen (PSA) levels in the intermediate range of 4 to 10 ng/mL. The following variables were analysed: PSA, %fPSA, and LDH. Two categories of patients were included in the analysis: NOT PC and PC. We studied 134 patients, 112 had NOT PC and 22 had PC. We defined the following multivariable score (S): S = A + B, where A and B are coefficients of LDH and %fPSA, respectively. AUC values were 0.719 (p = 0.0036), 0.749 (p = 0.0082), and 0.816 (p = 0.0001) for %fPSA, LDH, and S, respectively. Using the proposed S increases by 18% specificity compared to only using the %fPSA parameter. LDH in combination with %fPSA improves diagnostic performance for detection of PC compared to using only %fPSA.

Free to total serum prostate specific antigen ratio in symptomatic men does not help in differentiating benign from malignant disease of the prostate

Introduction:Free to total prostate specific antigen ratio (f/t PSA) has been used to help improving specificity of PSA in the range of 4-10 ng/ml based on the data on population based screening. There is no data on test characteristics of f/t PSA in men presenting with clinical symptoms of benign prostatic hyperplasia (BPH). This study is aimed to determine the usefulness of f/t PSA in symptomatic men.Methodology:From January 2006 to June 2012, men of 50-75 years with lower urinary tract symptoms (LUTS), normal rectal examination and PSA between 4-20 ng/ml had free and total PSA assessment. Men with clinical evidence of prostatitis, retention, history of 5α blocker reductase inhibitors and those who had surgery or biopsy on the prostate in last 3 months were excluded. Receiver operating characteristic curves were derived for f/t PSA and total PSA. The effect of age, prostate volume and Gleason score on the f/t PSA was also analyzed. All statistical analyses were performed on SPSS 16 (Chicago, USA).Results:Out of 170 men with the mean age of 67.4 ± 6.6 years, 43 (25.3%) had cancer on biopsy. Area under the curve for predicting the presence or absence of prostate cancer in all the men with f/t ratio was 0.63 (confidence interval [CI]: 0.54-0.71). The median value of f/t PSA for men with cancer was 5.5% (1-25%) and 9.2% (1-63%) for those with no cancer. Cut-offs derived at 95% specificity at PSA between 4-10 ng/ml and 4-20 ng/ml were 0.5% and 1% respectively. The specificity of f/t PSA ratio at cut-off levels 7%, 10% and 15% was 73%, 60%, 45% for PSA range of 4-10 ng/ml and 63%, 47% and 35% for PSA range of 4-20 ng/ml PSA. Age, prostate volume and Gleason grade did not show any effect on f/t PSA.Conclusion:In men with LUTS the specificity of various f/t PSA ratio cut-offs; described for population based screening, is too low to be used as an aid to defer the decision of biopsy in PSA ranges of 4-20 ng/ml.

Role of Serum Total PSA (Prostate Specific Antigen) and Free to Total PSA Ratio in the Diagnosis of Carcinoma Prostate

The objective of the study was to evaluate and compare the role of total and free/total ratio of serum prostate specific antigen level in diagnosing carcinoma prostate. A cross sectional study was conducted at the Department of Biochemistry, Dhaka Medical College (DMC) with collaboration of the Department of Urology, Dhaka Medical College Hospital (DMCH), Dhaka from July 2008 to June 2009. This study was carried out on 60 patients above 50 years of age who attended the Department of Urology, Dhaka Medical College Hospital, complaining of irritative or obstructive lower urinary tract symptoms (LUTS) suspected as clinically benign prostatic hyperplasia (BPH) or cancer prostate. It was aimed to assess the role of total and free/total ratio of serum PSA in diagnosis of BPH and carcinoma prostate with reference to histological diagnosis. All the cases were evaluated by history, physical examination including digital rectal examination, serum prostate specific antigen level, transabdominal/ trans-rectal ultra- sonogram. From all patients, blood sample were collected before digital rectal examination or any per urethral manipulation. Final diagnosis was obtained by histo-pathological examination, specimen being obtained by perrectal biopsy with biopsy-gun. Histopathological examination detected prostate cancer in 20 out of 60 patient and 17 of these Cap 20 have a total PSA ? 4 ng/ml and only 3 have total PSA ? 4 ng/ml. 18 of these 20 have free to total ratio ?0.16 and 02 have f/t ratio ?0.16. Among 60 patients, 40 patients were detected BPH on histopathological diagnosis. 20 of these BPH patient have tPSA ? 4 ng/ml and 20 of BPH have tPSA ? 4 ng/ml. 38 of 40 BPH patient have f/t ratio &gt;0.16 and 2 of 40 patient are f/t ratio ?0.16. Receiver operating characteristic analysis indicated a threshold f/t ratio ? 0.16 was optimum discriminatory level. The sensitivity of total serum PSA (at cut off value of &gt;4 ng/ml) in correctly differentiating prostatic carcinoma of those who have the condition is 85%, while the specificity of the test in correctly detecting those who do not have the disease is 50%. The PPV is 45.9%, NPV is 87% and accuracy is 61.7%. The sensitivity of free/total serum PSA (at cut off value of 0.16 ng/ml) in correctly differentiating prostatic carcinoma from BPH is 90%, while the specificity of the test in correctly detecting those who do not have prostatic carcinoma is 95%. The PPV of the test is 90% and the NPV of the test is 95%. The overall accuracy of the test is 93.3%. This study showed significant difference of total and free/total ratio of serum prostate specific antigen (PSA) in differentiating benign prostatic hyperplasia (BPH) from carcinoma prostate. Receiver operating characteristic curves showed advantage for the f/t PSA ratio when compared with total PSA in detecting prostate cancer. From the study it may be concluded that total and f/t ratio of prostate specific antigen (PSA) is a useful marker in diagnosis of carcinoma prostate. Free/total ratio is more accurate than total PSA. DOI: http://dx.doi.org/10.3329/bjmb.v4i1.13778 Bangladesh J Med Biochem 2011; 4(1): 21-26

Health advocacy in urology training

The article by Michael Leveridge and colleagues1 raises an issue that is not often addressed in the urology literature, and should provoke some discomfort and discussion. Every physician involved in resident training and evaluation is aware that, about 10 years ago, the Royal College redefined the goals of training beyond the acquisition of expertise in a specialty. Six additional roles were added to that of medical expert, including health advocate, communicator, collaborator, manager, scholar and professional. Resident evaluations now require the resident's performance in each of these areas to be determined on a regular basis. For residents working hard to master surgical and clinical skills and basic and clinical sciences, the challenge represented by the acquisition of expertise in these other 6 roles, and (perhaps even more critically) the need to demonstrate that the skill sets involved have been acquired, is large. One of these roles, the scholar (i.e., researcher), has been accepted for 100 years as an important one in surgery. Canadian residents are encouraged to obtain some research experience, and indeed this a requirement of some programs. However, it is likely that most urologists involved in resident training believe that the teaching involved in the 5 roles beyond medical expert and scholar occurs implicitly, by example, rather than by explicit instruction. We teach communication skills by being good communicators; we demonstrate collaborator skills by collaborating; and so on. The article by Leveridge and colleagues confirms that explicit training in health advocacy is rare in residency training and that active participation in health advocacy projects is virtually nonexistent. The Royal College presumably considers that this is a deficiency. But is it? Becoming a medical expert involves the acquisition of multiple skill sets. Five years of residency training after medical school is a short time to develop proficiency. Would formal training in the other 5 roles, beyond expert and scholar, represent a dilution of the focus on knowledge acquisition and clinical and surgical skills? Or would resident instruction and opportunity for involvement in, for example, health advocacy, raise the level of expertise achieved in other areas? Does this matter? We welcome our readers' views on this question. The Laval group continues their remarkable productivity in the area of cancer biomarkers. Stephan Bolduc and colleagues2 report that urinary prostate specific antigen (PSA), and particularly the urinary to serum PSA ratio, discriminate between benign prostatic hyperplasia and prostate cancer in men with mild PSA elevation. Urinary PSA is appealing because of its availability and low cost. It would have been interesting to know how urinary PSA performs compared with free versus total ratio, or to a multi-parameter nomogram approach incorporating other risk factors. We look forward to more evidence regarding the utility of this assay.

The Electromagnetic Detection of Prostatic Cancer: Evaluation of Diagnostic Accuracy

To evaluate the accuracy of the TRIMprob in the diagnosis of prostate neoplasm. Consecutive patients referred for prostate biopsy were prospectively enrolled. Patients had history taken, physical examination by digital rectal examination (DRE) of the prostate, assessment of total and free serum prostate-specific antigen (PSA) levels, prostate transrectal ultrasonography (TRUS), and TRIMprob test. Indications for prostate biopsy included one or more of the following conditions: total serum PSA levels of 4.0 ng/mL or more, free/total serum PSA ratio of 0.18 or less, positive results on DRE, and suspicious findings on TRUS. Twelve-core, TRUS-guided biopsies were performed with local anesthesia. A blinded investigator performed the TRIMprob test; the lowest value of the signal at 465 MHz was looked for and recorded, although data of the electromagnetic signal at 930 and 1295 MHz were also recorded. One hundred eleven patients (aged 64.9 +/- 8.1 years, mean +/- standard deviation), enrolled between November 2004 and August 2005, were analyzed. Total serum PSA level was 8.4 +/- 3.6 ng/mL, and free/total serum PSA ratio was 0.15 +/- 0.7. TRIMprob sensitivity for the diagnosis of prostate cancer was 0.86%; specificity and positive and negative predictive values were 0.60 and 0.88; accuracy was 72%. TRIMprob accuracy outperformed any other diagnostic parameter considered, including the rule of chance. The association of TRIMprob and DRE offered a sensitivity and a negative predictive value of 0.86% or greater. TRIMprob had the highest accuracy rate, among all other tests, for the diagnosis of prostate cancer. Electromagnetic detection with the TRIMprob test seems to be a promising technology and a useful additional tool for the early detection of prostate cancer.

Urinary/serum prostate-specific antigen ratio: Comparison with free/total serum prostate-specific antigen ratio in improving prostate cancer detection

Objectives To test the previously reported hypothesis, that the urinary/total serum (U/S) prostate-specific antigen (PSA) ratio improves the detection of prostate cancer, by evaluating the clinical usefulness of the U/S PSA ratio and comparing it with the free/total (F/T) serum PSA ratio. Methods A total of 165 patients undergoing transrectal ultrasound-guided prostate biopsy were prospectively included in this multicenter study. In all patients, PSA was measured from preoperative serum and 12-hour urine specimens in a centralized laboratory. Results Prostate cancer was identified in 83 of 165 patients. The differences between patients with and without prostate cancer were statistically significant ( P <0.001) when considering the total PSA value (median, 10.2 ng/mL and 6.6 ng/mL respectively), F/T serum PSA ratio (0.11 and 0.18), and U/S PSA ratio (1.2 and 4.2). In the group of 79 patients with a PSA level between 4 and 10 ng/mL, receiver operating characteristic curves showed that the U/S PSA ratio was associated with a larger area under the curve (0.63; 95% confidence interval, 0.51 to 0.73) than the total PSA value (0.55; 95% confidence interval, 0.43 to 0.66) or F/T serum PSA ratio (0.60; 95% confidence interval, 0.49 to 0.71). The U/S PSA ratio did not correlate with patient age or prostate volume. Conclusions Our results confirmed that the U/S PSA ratio may be a useful test in prostate cancer detection when the total serum PSA level is between 4 and 10 ng/mL. The F/T serum PSA ratio and U/S PSA ratio did not correlate. This suggests that these two tests could complement each other.

Free/total serum prostate-specific antigen ratio: how helpful is it in detecting prostate cancer?

To determine whether the use of free/total (f/t) serum prostate specific antigen (PSA) ratio would help reduce the number of prostate biopsies performed without compromising the detection of prostate cancer. in the setting of a transrectal ultrasonography (TRUS) clinic. The study included 93 consecutive patients referred to the clinic for TRUS and biopsy. Serum samples were assessed for total PSA and free PSA, and the f/t PSA ratio calculated: 70 biopsies were taken. Patients over the age of 70 years with TRUS findings consistent with benign prostatic hyperplasia and with PSA levels < 10 ng/mL were not biopsied. Tumour was detected in 23 patients; receiver operating characteristic curves showed no advantage for the f/t PSA ratio when compared with total PSA in detecting prostate cancer. If a f/t PSA ratio of < 0.15 had been used to determine the necessity for biopsy in the group with a total PSA of 4-10 ng/mL, then two-thirds of all tumours would have been undetected. The f/t PSA ratio had no advantage over total PSA in improving specificity at a given sensitivity for detecting prostate cancer. Therefore, it cannot be recommended as a means of decreasing unnecessary biopsies in patients with a raised PSA level and/or an abnormal digital rectal examination. This applied particularly to the group of patients with a total PSA of 4-10 ng/mL.

The Free-to-Total Serum Prostate Specific Antigen Ratio for Staging Prostate Carcinoma

The Free-to-Total Serum Prostate Specific Antigen Ratio for Staging Prostate Carcinoma

The Free-to-Total Serum Prostate Specific Antigen Ratio for Staging Prostate Carcinoma

We analyzed the relationship between the free-to-total PSA ratio and prostate cancer tumor stage and grade compared to total serum PSA. In 123 patients clinical and pathological grade and stage were related to total serum PSA and free-to-total PSA ratio. Total serum PSA paralleled clinical staging of prostate cancer. The distributions of total serum PSA and the free-to-total PSA ratio were significantly different between benign and malignant diseases (any stage), and between any T category and nodal disease. For serum PSA significant differences were noted between the distributions of men with locally confined (stages T1 and T2) and locally extended (stage T3) disease, and between all T categories and systemic metastatic disease. This finding was not noted for the free-to-total PSA ratio. The free-to-total PSA ratio has no additional value in clinical staging of prostate carcinoma compared to serum PSA. The free-to-total PSA ratio may be considered the result of cell differentiation and not an indicator of tumor load.

Longitudinal analysis of serial measurements of free and total PSA among men with and without prostatic cancer

Objectives Evaluation of free and total serum prostate specific antigen (PSA) levels before diagnosis of prostate cancer. Methods Free and total PSA levels were measured on frozen sera samples of 26 men with no history of prostate disease (controls), 29 men with a histologic diagnosis of benign prostatic hyperplasia (BPH) made at simple prostatectomy (BPH cases), and 23 men with a histologic diagnosis of prostatic cancer (cancer cases). Longitudinal regression analysis was used to evaluate PSA levels as a function of years before diagnosis of prostate disease. Results On average, mean total serum PSA was statistically significantly greater for subjects with cancer (5.0 ng/mL ± 0.9) versus BPH (2.8 ng/mL ± 0.3) and control subjects (0.8 ng/mL ± 0.1) by 4 years before diagnosis, whereas free PSA levels were similar among groups at 4 years before diagnosis. The ratio of free to total serum PSA continuously decreased among cancer cases over the decade before cancer diagnosis. At a time when mean total and free PSA levels were similar among groups (8 years before diagnosis), the ratio of free to total PSA was statistically significantly lower for cancer cases (0.13 ± 0.01) compared with BPH (0.17 ± 0.01) and control cases (0.21 ± 0.02). Use of a free to total PSA ratio of ≤0.12 when total PSA was between 4.0 and 10.0 ng/mL resulted in the highest sensitivity (76%) and specificity (94%) for diagnosis among subjects with and without cancer. Lowering the reflex range to 2.5 ng/mL increased false positive tests more than it increased sensitivity. Conclusions The ratio of free to total PSA is the earliest serum marker predicting a subsequent diagnosis of prostate cancer. Measurement of the free to total serum PSA ratio would appear to reduce false positive results among men without prostate cancer.

Benign hyperplastic nodules that originate in the peripheral zone of the prostate gland.

To describe a benign nodular lesion in the peripheral zone (PZ) of the prostate gland. In 1,087 patients, the features of 722 focal lesions in the PZ or central zone of the prostate on transrectal ultrasound (TRUS) scans were retrospectively compared with histologic findings in biopsy samples. In 18 patients (5.5% of the 328 patients with benign lesions), benign hyperplasia was found in a focal, nodular lesion obviously located within the PZ. On TRUS scans, the nodules were well circumscribed, ovoid or round, and slightly hypoechoic (n = 11) or isoechoic (n = 7). The isoechoic lesions were surrounded by an anechoic halo. One nodule was an incidental sonographic finding; the 17 others were felt as firm (n = 11) or soft (n = 6) at digital rectal examination. The ratio of serum prostate-specific antigen (PSA) level to prostatic volume was low (< 0.1), except in one patient (0.24). Some sonographic features and the normal PSA values might suggest a benign nodule in the PZ, but TRUS-guided biopsies and histologic correlation are necessary to confirm the diagnosis.

Usefulness of prostate specific antigen/gamma-seminoprotein ratio for diagnosis of prostate cancer

Prostate specific antigen (PSA) and gamma-seminoprotein (gamma-Sm) are used as tumor markers of the prostate cancer. However, the serum concentrations of PSA and gamma-Sm are frequently increased in patients with benign prostatic hypertrophy (BPH). We measured the ratio of serum PSA to gamma-Sm concentration (P/S ratio), and evaluated its usefulness for diagnosis of prostate cancers. Between April 1988 and July 1992, 162 men underwent prostatic biopsy and/or TUR-P, and were diagnosed pathologically. Of 162 patients, 112 were diagnosed as BPH and 50 were diagnosed as prostate cancer. Of 24 patients with serum PSA level of > 20 ng/ml, 23 (95.8%) were prostate cancer, while, of 79 patients with serum PSA level of 3.0-20 ng/ml, 23 (29.1%) were prostate cancer. The sensitivity and the specificity for PSA were 92.0% and 49.1%, respectively. Of 85 patients with serum gamma-Sm level of > 4.0 ng/ml, 30 (35.3%) were prostate cancer. The sensitivity and the specificity for gamma-Sm were 60.0% and 50.9%, respectively. A mean +/- SD of P/S ratio in 112 patients with BPH was 0.954 +/- 0.591. While, the mean +/- SD of P/S ratio was 16.295 +/- 58.584 in all prostate cancer patients, and 2.031 +/- 0.654 in 27 prostate cancer patients with serum PSA level of < or = 20 ng/ml. P/S Ratio in prostate cancer patients with serum PSA of < or = 20 ng/ml as well as in all prostate cancer patients were significantly higher than P/S Ratio of BPH patients (p < 0.0001). Of 55 patients with P/S Ratio of > or = 1.50, 45 (81.8%) were prostate cancer and 10 (18.2%) were BPH. While, of 107 patients with P/S Ratio of < 1.50, 102 (95.3%) were BPH and 5 (4.7%) were prostate cancer. The sensitivity and the specificity for P/S Ratio were 90.0% and 91.1%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)