Relationship between serum prostate-specific antigen and prostate volume in Korean men with benign prostatic hyperplasia: a multicentre study

OBJECTIVES: To evaluate the relationship between prostate specific antigen (PSA) and prostate volume (PV) in Korean men, as PV is a key predictor of both disease progression and response to medical therapy in patients with benign prostatic hyperplasia (BPH), and PSA has been suggested as a proxy marker to estimate the total PV, mainly in Caucasians. PATIENTS AND METHODS: From 1999 to 2004, men aged 50-79 years with lower urinary tract symptoms (LUTS) and BPH were enrolled into this multicentre study. The analyses included 5716 patients presenting to 11 medical centres with LUTS (International Prostate Symptom Score >8, peak urinary flow rate <15 mL/s); they had a mean age of 64.3 years, mean baseline PV of 36.9 mL, and mean baseline PSA level of 2.2 ng/mL. Men with a baseline PSA of >10 ng/mL were excluded, to reduce the likelihood of including occult prostate cancer. A biopsy was taken in those with suspicious findings on a digital rectal examination or serum PSA level of >4 ng/mL, to exclude prostate cancer. Receiver operating characteristic (ROC) curves were constructed to evaluate the ability of serum PSA to predict threshold PV in men with BPH. RESULTS: The PV and serum PSA level had an age-dependent log-linear relationship, the strength of which increased with age. The ROC curve analysis showed that PSA had good predictive value for various prostate volume thresholds (30, 40 and 50 mL). CONCLUSIONS: The PSA-PV relationship in Korean men is similar to that in Caucasians, but Korean men have a slightly lower PSA level and a smaller PV than Caucasians. The approximate age-specific criteria for detecting Korean men with a PV of >40 mL were a PSA level of >1.3 ng/mL, >1.7 ng/mL and >2.0 ng/mL for men with BPH in their sixth, seventh and eighth decade, respectively.     

Do differences in age specific androgenic steroid hormone levels account for differing prostate cancer rates between Arabs and Caucasians?

OBJECTIVE: Factors responsible for the low incidence of clinical prostate cancer in the Arab population remain unclear, but may be related to differences in androgenic steroid hormone metabolism between Arabs and other populations, especially as prostate cancer is believed to be androgen dependent. We therefore measured the levels of serum androgenic steroids and their binding proteins in Arab men and compared results obtained with values reported for Caucasian populations to determine if any differences could at least partially account for differences in incidence of prostate cancer rates between the two populations. METHODS: Venous blood samples were obtained from 327 unselected apparently healthy indigenous Arab men (Kuwaitis and Omanis) aged 15-79 years. Samples were also obtained from 30 Arab men with newly diagnosed prostate cancer. Serum levels of total testosterone (TT), sex hormone binding globulin (SHBG), derived free androgen index (FAI); adrenal C19 -steroids, dehydroepiandrosterone sulfate (DHEAS) and androstenedione (ADT) were determined by chemiluminescent immunoassay. Age specific reference intervals, mean and median for each analyte were determined. Frequency distribution pattern for each hormone was plotted. The reference range for hormones with normal distribution was mean +/- 2SD and 2.5-97.5% for those with non-normal distribution. The mean serum levels of the hormones in Arab men with prostate cancer were compared with values in healthy age-matched Arab men. RESULTS: There was a significant decrease between the 21-29 years age group and the 70-79 years age group for TT (-38.77%), DHEAS (-70%), ADT (-36%) and FAI (-63.25%), and an increase for SHBG (+64%). The calculated reference ranges are TT (2.73-30.45 nmol/L), SHBG (6.45-65.67 nmol/L), FAI (14.51-180.34), DHEAS (0.9-11.0 micromol/L) and ADT (0.54-4.26 ng/mL). The mean TT, SHBG, DHEAS and ADT in Arab men were significantly lower than those reported for Caucasians especially in the 21-29 years age group. Arab men with newly diagnosed prostate cancer had higher serum TT (P < 0.7), ADT (P < 0.2), SHBG (P < 0.2) and lower DHEAS (P < 0.008) compared to aged matched controls. CONCLUSIONS: Serum TT, SHBG, DHEAS and ADT levels are significantly lower in Arab men compared to those reported for Caucasian men, especially in early adulthood. Arab men with newly diagnosed prostate cancer have higher circulating androgens compared to healthy controls. We suggest that low circulating androgens and their adrenal precursors in Arab men when compared to Caucasians may partially account for the relatively lower risk for prostate cancer among Arab men.     

High serum prostate-specific antigen levels in the absence of prostate cancer in Middle-Eastern men: the clinician's dilemma

OBJECTIVE: To investigate the common causes of total serum prostate-specific antigen (PSA) values of> 10 ng/mL in an Arab population, as in the USA and Europe the risk of prostate cancer is considered high in men with such PSA levels. PATIENTS AND METHODS: Serum total PSA was measured in men presenting to our hospital as part of the investigation for prostate cancer screening and/or in elderly men with prostatism. Men with a serum PSA level of> 10 ng/mL were further investigated by transrectal ultrasonography (TRUS) of the prostate and biopsy of suspicious lesions for histological diagnosis. In addition, the percentage of free PSA, PSA velocity and PSA density were determined. All the patients included in this study were men of Arab origin residing in Kuwait. RESULTS: In all, 1700 men (mean age 55.6 years, range 35-94) were assessed; of these, 161 had a serum PSA of> 10 ng/mL, attributable to benign prostatic hyperplasia (BPH) in 110 (68%), BPH with histological features of prostatitis in 33 (21%) and prostate cancer in 18 (11%). TRUS of the prostate in 143 of the 161 men with either BPH or BPH with prostatitis showed varying grades of intraprostatic calcifications in 22 (15%). Both PSA density and percentage free PSA did not contribute to determining the causes of total PSA levels of> 10 ng/mL. There was a progressive decline in PSA in all patients with BPH and prostatitis, except one who at re-biopsy had prostate cancer (T1N0M0, G1). CONCLUSION: Total PSA values of> 10 ng/mL in Arab men may be a result of BPH, BPH with prostatitis or prostate cancer, in that order. A gradual decline in total PSA (decreased PSA velocity) with time to < 4 ng/mL often confirms the diagnosis of BPH with prostatitis. The percentage of free PSA and PSA density may not be helpful in diagnosing prostate cancer with certainty in these patients. Compared with Caucasians in the USA and Europe, BPH and BPH with prostatitis appear to be more frequent causes of serum PSA levels of> 10 ng/mL in Arab men.     

Prostate specific-antigen distribution in asymptomatic Canadian men with no clinical evidence of prostate cancer

OBJECTIVE: To examine prostate specific-antigen (PSA) levels and percentage free/total PSA (f/tPSA) distributions as well as digital rectal examination (DRE) profiles in asymptomatic Canadian men with no established prostate cancer diagnosis, as recent data indicate that a man's risk of developing prostate cancer is higher if his baseline PSA level is above the median for his age group. SUBJECTS AND METHODS: We used data obtained during an early prostate cancer-detection event. An invitation to an onsite DRE, PSA level and f/tPSA assessment was accepted by 313 men. Serum PSA level and f/tPSA were measured before the DRE. A suspicious DRE and/or PSA level of > or = 2.5 ng/mL or f/tPSA of < or = 15% represented indications for a systematic 12-core ultrasonography-guided prostate biopsy. RESULTS: Of all the 313 men, most (235, 75%) had PSA levels of 0.01-1.53 ng/mL and an f/tPSA of >15% (285, 91.1%). The median (range) PSA level was 0.8 (0-34.2) ng/mL and f/tPSA was 27.4 (6.7-100)%. Age-specific median PSA levels and f/tPSA were, respectively, 0.7, 0.9, 1.0, 1.5 ng/mL and 31%, 27%, 26%, 25% for men aged 40-49, 50-59, 60-69 and 70-79 years. A suspicious DRE was recorded in 55 (17.6%) men, with eight (8.8%), 26 (20.0%), 14 (20.6%), and seven (28.9%) having suspicious DRE findings according to above age categories. Overall, seven (2.2%) prostate cancers were detected. CONCLUSION: The median age-specific baseline PSA levels and f/tPSA represent valuable indicators of prostate cancer risk. The population-specific baseline median PSA level should not be >1.0 ng/mL and the baseline f/tPSA should be >30%. Men with values outside of these ranges should be considered at greater risk of prostate cancer.     

Putative role of serum insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) levels in the development of prostate cancer in Arab men

INTRODUCTION: The incidence of clinical prostate cancer in the Arab population is among the lowest in the world. High serum IGF-1 level has been implicated as a possible risk factor for the development of prostate cancer in Caucasians. The purpose of this study was to determine serum IGF-1 and IGFBP-3 levels in healthy Arab men and in Arab men with newly diagnosed benign prostatic hyperplasia (BPH) and prostate cancer, and to compare these values with values reported in Caucasians. PATIENTS AND METHODS: Subjects were recruited in two groups: (a) indigenous, healthy Arab men aged 15-90 y (n = 383); (b) Arab men with newly diagnosed prostate cancer (n = 30) or BPH (n = 40). Blood was obtained from fasting patients and volunteers, between 8:00 a.m. and 12:00 noon. The serum concentrations of IGF-1 and IGFBP-3 were determined using Immunoradiometric assay (IRMA) kits. RESULTS: As in Caucasians, serum IGF-1 and IGFBP-3 levels declined with age in Arab men. The mean +/- s.d. of serum IGF-1 levels in healthy Arab men in the age group 15-20, 51-60, 61-70 y were lower (376.2 +/- 153.2, 134.9 +/- 105.7 and 89.6 +/- 48.4 ng/ml, respectively), compared to values reported for similarly aged Caucasians. Arab men with newly diagnosed prostate cancer had significantly higher serum IGF-1 level (P < 0.01) and lower IGFBP-3 levels (P < 0.01) compared to age-matched Arabs without the disease. CONCLUSIONS: Arab men have lower serum IGF-1 levels compared to Caucasians and this may be an important factor in the explanation of the low incidence of prostate cancer in the Arab population.     

Reference ranges for serum prostate-specific antigen in black and white men without cancer

Objectives. To determine the age- and race-specific prostate-specific antigen (PSA) distributions in healthy men in central South Carolina and to compare these to data from other studies.Methods. Two thousand ninety-two black men aged 40 to 69 years and white men aged 50 to 69 years from the general population in 11 counties of central South Carolina participated in a prostate cancer educational program. Seventy-two percent of the participants were black—about double the proportion in the general population—and 63% of the men (1319 of 2092) subsequently obtained a PSA determination from their own physician. The distribution of serum PSA was compared with distributions from the Olmsted County study and from the Walter Reed Army Medical Center/Center for Prostate Disease Research study.Results. Older men without cancer had higher PSA levels. Regression analyses yielded an associated increase of about 3.3% per year. Reference ranges for normal PSA in men without cancer (based on their sample 95th percentiles) were zero to 1.9, 3.8, and 5.7 ng/mL in black men aged 40 to 49, 50 to 59, and 60 to 69 years, and zero to 2.7 and 4.9 mg/mL in white men aged 50 to 59 and 60 to 69 years, respectively.Conclusions. Reference ranges for normal serum PSA levels should take into account the population from which they are derived and to which they will be applied. Reference ranges that are useful in the general population can differ from those that are appropriate in a hospital setting. For the general population in central South Carolina, reference ranges for serum PSA levels are lower than previously published reference ranges, particularly among black men.     

Prostate gland volume is a strong predictor of biopsy results in men 70 years or older with prostate-specific antigen levels of 2.0–10.0 ng/mL

PURPOSE: The incidence of prostate cancer, benign prostatic enlargement and serum level of prostate-specific antigen (PSA) increase with patient age. Intermediate elevation of PSA in elderly populations is apt to be considered insignificant. We evaluated the impact of PSA and prostate volume on the presence of non-palpable prostate cancer in elderly men with an intermediate level of PSA. MATERIALS AND METHODS: Clinical records of 154 men 70 years or older, with non-cancerous digital rectal examination findings and with serum PSA levels of 2.0-10.0 ng/mL, who underwent initial 6- to 10-core transrectal prostate biopsy, were reviewed for prostate volume, number of biopsy cores, PSA and associated parameters. Stepwise logistic regression and receiver operating characteristic (ROC) models were used to determine the impacts of the parameters on the biopsy results. RESULTS: Overall cancer detection rate was 40/154 or 26.0%. Prostate-specific antigen showed no significant association with the presence of prostate cancer (P = 0.59, Mann-Whitney U-test), while prostate volume did (P < 0.0001). On stepwise logistic regression analysis, prostate volume (P = 0.024, 95% CI 1.008-1.116) and biopsy core density (P = 0.017, 95% CI 4.76-7.12 x 10(6)) were independently associated with a cancer diagnosis, whereas PSA density was not an independent factor for a positive biopsy result. The area under the ROC curve for prostate volume was significantly superior to that of PSA (0.802 vs. 0.529; P = 0.012). CONCLUSIONS: In men 70 years or older with gray zone PSA, prostate cancer patients are equally distributed over any PSA range. Although PSA has less impact on cancer presence than mere prostate volume, prostate cancer would be detected in a substantial proportion of older patients with PSA levels of 2.0-10.0 ng/mL.     

Standard Versus Age-Specific Prostate Specific Antigen Reference Ranges Among Men With Clinically Localized Prostate Cancer: A Pathological Analysis

Purpose

Age-specific prostate specific antigen (PSA) reference ranges have been suggested to account for the age-dependent nature of the serum PSA concentration. It has been hypothesized that reference ranges of 0 to 2.5 ng./ml. serum PSA (40 to 49 years), 0 to 3.5 ng./ml. (50 to 59 years), 0 to 4.5 ng./ml. (60 to 69 years) and 0 to 6.5 ng./ml. (70 to 79 years) would detect fewer (potentially insignificant) prostate cancers in older men and more (potentially curable) cancers in younger men.

Materials and Methods

To investigate the pathological stage of tumors that would be affected by the use of age-specific PSA reference ranges, we reviewed the medical records for 4,597 men with clinically localized (stage T1c, T2 or T3a) prostate cancer, with an average age of 62 plus/minus 7 years (range 38 to 76), who underwent radical prostatectomy between 1984 and 1994 at our institutions. Favorable pathological results were defined as organ-confined disease or capsular perforation with a Gleason score of less than 7, and unfavorable pathological results were defined as capsular perforation with a Gleason score of 7 or more, seminal vesicle invasion or lymph node involvement.

Results

Overall, 18 percent of the men had PSA levels less than the standard PSA reference range (4.0 ng./ml.) compared to 22 percent when using the age-specific ranges. There were 74 more cancers detected in men younger than 60 years with the use of age-specific ranges, of which 81 percent had favorable pathological results. Among the men 60 years or older, 191 of 252 cancers (76 percent) not detected by using age-specific ranges were of favorable pathological status. Of those cancers not detected in older men with the age-specific ranges less than 3 percent were also stage T1c and 95 percent of these undetected T1c cancers were of favorable pathological status. Age-specific PSA reference ranges increased the potential for detection of prostate cancer by 18 percent in the younger men and decreased the detection by 22 percent in the older men.

Conclusions

Among these men with clinically localized prostate cancer, age-specific PSA reference ranges increased the detection of more potentially curable tumors in young men and decreased the detection of less advanced tumors in the older men compared to the standard reference range of 4.0 ng./ml. Among older men with nonpalpable (stage T1c) tumors age-specific PSA reference ranges would have detected fewer tumors. However, 95 percent of these “missed” tumors would have had favorable pathological findings.     

Serum prostate‐specific antigen is better correlated to body surface area than body mass index in a population of healthy Korean men

It has been suggested that the larger vascular volume among obese men causes a dilution effect, decreasing the concentration of serum prostate‐specific antigen (PSA). However, plasma volume is proportional to body surface area (BSA) rather than to body mass index (BMI). We determined whether serum PSA level is better correlated to BSA than BMI in a population of ostensibly healthy Korean men. Data from 2604 men who visited our health promotion center were evaluated. All men underwent anthropometric measurements, digital rectal examination, serum PSA determination, and transrectal ultrasound examination. The correlation between serum PSA and other parameters was statistically analyzed. The mean age was 49.9 years and the mean serum PSA level was 1.14ng/mL. The multivariate analysis revealed that the serum PSA was positively correlated with age, prostate volume, and negatively correlated with BSA only and not with BMI. In addition, BSA, rather than BMI, was the significant factor in predicting the prostate volume. Our results suggest that men with larger BSA (rather than BMI), have larger prostate volumes, and lower serum PSA.     

Age-specific PSA reference ranges in a group of non-urologic patients

Age-specific serum PSA reference ranges have recently been proposed to be more sensitive in young and more specific in elder patients. However, some conflicting results have been reported from different centers. In order to establish age-specific PSA reference ranges for our country, we measured the serum PSA levels of 400 healthy men over 40, between February 1995 and June 1996. Our study population consisted of men who had either PSA values lower than 4.0 ng/ml and normal digital rectal examination or negative prostatic biopsies taken for any reason. IMX assay was used for PSA determination in all patients. Mean PSA values and standard deviations for each age group were: 1.7±1.1 ng/ml for 40–49 years (n=28), 2.0±1.2 ng/ml for 50–59 years (n=110), 2.9±1.7 ng/ml for 60–69 years (n=158) and 3.5±2.0 ng/ml for 70–79 years (n=104). We conclude that further studies of larger series will lead us to standardize age-specific reference ranges in our country and, accordingly, we will be able to select the candidates for prostate biopsy more adequately.     

Lower urinary tract symptoms and risk of prostate cancer in Japanese men

Our aim was to investigate whether or not men with lower urinary tract symptoms are at increased risk of prostate cancer. A total of 3511 men aged 50-79 years who underwent mass screening for prostate cancer between 2002 and 2004 for the first time, and completed the International Prostate Symptom Score (IPSS) questionnaire at the time of the prostate specific antigen (PSA) test, were enrolled in the present study. All men with PSA values greater than 4.0 ng/mL were advised and encouraged to undergo transrectal systematic sextant biopsy. The number of cancers subsequently detected was compared between men with IPSS scores of 0-7 and 8-35. Of the 3511 men, 219 (6.2%) had PSA values greater than 4 ng/mL, 178 (5.1%) underwent biopsy, and 51 (1.5%) were found to have prostate cancer. Although the PSA positivity rate for men with IPSS scores of 8-35 was significantly higher than that in the 0-7 group, there were no significant intergroup differences in the cancer detection rates for biopsied men and for total screened subjects. Multivariate logistic regression analysis revealed that prostate volume was the dominant predictor for the detection of prostate cancer, followed by PSA level, but the IPSS made no significant contribution. No significant difference was noted in the IPSS scores between men with cancer and the others of the same age group. Symptomatic Japanese men are not at higher risk of prostate cancer despite their higher PSA values compared with asymptomatic men of the same age group.     

上海市BPH人群中PSA的年龄特异性分布

目的：建立上海市BPH人群的血清总前列腺特异抗原（T-PSA）的各年龄段特异性的参考值范围。方法：收集2006年12月-2008年4月上海交通大学附属第一人民医院BPH及可疑前列腺癌的4185例上海患者的血清T—PSA值及游离PSA（F—PSA）值。所有患者均有国际前列腺症状评分（I-PSS）、B超检查及直肠指诊。采用单因素直线回归分析方法分析患者T—PSA、F-PSA及F／T比值与年龄的关系。结果：4110例BPH患者血清T—PSA及F-PSA与年龄呈正相关（r=0．28,P〈0．0001及r=0．28,Pd0．0001）,F／T比值与年龄呈负相关（r=-0．05,P=0．0005）;上海市人群T—PSA值的年龄特异性分布大致为：40～49岁者为0～2．2ng／ml,50～59岁者为O～3．4ng／ml,60～69岁者为0～5．5ng／ml,70～79岁者为O～6．7ng／ml,80～89岁者为O～8．4ng／ml,90～99岁者为0～9．4ng／ml。上海市BPH人群较北京市BPH人群各年龄段特异性T-PSA值高,差异有显著统计学意义（t=4．63,P=0．01）;较西安市健康人群高,差异有显著统计学意义（t=3．42,P=0．04）;较黑人社区人群低,差异有显著统计学意义（t=-0．62,P=0．0085）。结论：上海市BPH患者血清T—PSA和F-PSA水平与年龄呈正相关,而F／T比值与年龄呈负相关。血清T—PSA的年龄特异性分布有地区及种族差异。     

Prostate-specific antigen testing in hypogonadism: implications for the safety of testosterone-replacement therapy

Hypogonadal men have lower prostate volumes and serum prostate-specific antigen (PSA) levels than age-matched controls. When present, prostate cancer in hypogonadal men is more aggressive than in eugonadal men, and given the lack of specificity of PSA for diagnosing prostate cancer, a more accurate test would be desirable in hypogonadal men. Once testosterone-replacement therapy is started in hypogonadal men, PSA levels should be measured regularly; however, there is often an initial rise 3-6 months after starting treatment. A rise of >0.5 ng/mL within this time requires further investigation.     

Volume-adjusted prostate-specific antigen (PSA) variables in detecting impalpable prostate cancer in men with PSA levels of 2-4 ng/mL: transabdominal measurement makes a significant contribution

OBJECTIVE: To examine whether prostate-specific antigen (PSA) levels adjusted according to prostate volume improve prostate cancer detection using transrected biopsies in men with PSA levels of 2-4 ng/mL, and benign findings on a digital rectal examination (DRE). PATIENTS AND METHODS: Men aged < or = 79 years and with serum PSA levels of 2-4 ng/mL and normal DRE findings were prospectively enrolled. Eligible patients were recommended for transrectal prostate biopsies after measuring prostate volumes with transrectal (TRUS) and transabdominal (TAUS) ultrasonography, and transition zone volumes with TRUS. In addition to PSA levels and the free-to-total PSA ratio, volume-adjusted PSA levels, PSA densities determined by TRUS (PSAD(TRUS)), and TAUS (PSAD(TAUS)), and PSA transition zone densities (PSATzD) were compared using receiver operating characteristic analysis. RESULTS: Prostate cancer was diagnosed in 31 (22%) of the 139 men who had prostate biopsies. The area under the curve (AUC) of PSAD(TRUS) (0.796) and PSATzD (0.792) was similar and significantly greater than that of PSA (AUC 0.588) and the free-to-total PSA ratio (AUC 0.658). PSAD(TAUS) was a significantly better indicator of prostate cancer than PSA levels alone (P = 0.043). CONCLUSION: As predictors of prostate cancer, there were no significant differences between PSAD(TRUS) and PSATzD. Although PSAD(TAUS) was worse than PSA variables adjusted by total and transition zone prostate volumes determined by TRUS, it was a better predictor than the PSA value alone in men with a low PSA level. These results indicate that TAUS is worthwhile where the routine use of TRUS before biopsy is difficult.     

Predicting the probability of significant prostate cancer in Japanese men with serum prostate‐specific antigen less than 10 ng/mL: Development of a novel pre‐biopsy nomogram

Objectives: To develop and assess a new nomogram incorporating pre‐biopsy clinical data to predict significant prostate cancer in Japanese men with a serum prostate‐specific antigen (PSA) level of less than 10 ng/mL. Methods: We collected pre‐biopsy data from 620 men with a serum total PSA of less than 10 ng/mL. They included 491 men with a negative biopsy and 129 men who were confirmed to have histological prostate cancer and subsequently underwent radical prostatectomy. Clinically significant tumors were defined as those with a tumor volume larger than 0.5 mL and/or a Gleason score of 7 or more. Results: One hundred and seven prostatectomy patients had clinically significant cancers. Stepwise multivariate logistic regression analysis showed that digital rectal examination findings, PSA adjusted for transition zone volume and free‐to‐total PSA ratio were the significant independent predictors of significant cancers (P < 0.0001). Using these pre‐biopsy independent factors, a nomogram was developed to predict significant cancers. According to a receiver operating characteristics analysis, the nomogram showed an area under the curve of 0.831. Conclusion: This represents the first nomogram to predict the probability of clinically significant cancers before biopsy. This tool is most likely to be useful in the management of patients with moderate to elevated PSA.     

Diagnostic value of prostate-specific antigen-related parameters in discriminating prostate cancer.

BACKGROUND: Using the percentage (of total) of free prostate-specific antigen (PSA) in discriminating prostate cancer (CaP) from benign prostate hyperplasia (BPH) has not been fully delineated in Japanese men. To clarify the clinical significance of percent free PSA, various parameters, including total prostate volume, percent free PSA, PSA density (PSAD) and PSA density of transition zone volume (PSAT), were compared. METHODS: Ninety-seven patients who had visited one of three community-based hospitals, and whose total PSA value ranged from 4 to 20 ng/mL were prospectively enrolled in this study. Fresh sera were applied to measure the percent free PSA. RESULTS: Of the 97 patients, CaP and BPH were diagnosed in 24 (25%) and 73 patients, respectively. In discriminating CaP patients, the cutoff values of 17% for percent free PSA, 0.3 ng/mL per cm3 for PSAT, and 0.19 ng/mL per cm3 for PSAD yielded specificity levels of 56, 40 and 58% at sensitivity levels of 92, 92 and 79%, respectively. As for the 65 patients with intermediate PSA, range 410 ng/mL, and normal digital rectal examination, the percent free PSA and total prostate volume statistically discriminated CaP patients from BPH patients. A multiple logistic regression model proved percent free PSA to be the only significant discriminating factor (P=0.045; odds ratio, 9.06). CONCLUSIONS: This prospective study revealed percent free PSA to be a significant useful predictor in discriminating CaP from BPH in Japanese men.     

Measurement of serum zinc improves prostate cancer detection efficiency in patients with PSA levels between 4 ng/mL and 10 ng/mL

Aim： To investigate whether the measurement of serum zinc may improve the detection of prostate cancer （PCa） in men who had total prostate-specific antigen （PSA） levels higher than 4.1 ng/mL. Methods： A mass screening for PCa of 3940 men over 50 years old was undertaken using total serum PSA. Of the 190 men （4.8 %） with elevated PSA, 143 （3.6 %） underwent a transrectal ultrasonography （TRUS）-guided biopsy of the prostate, and 42 men （1% of total and 29.3 % of men undergoing biopsy） were found to have cancer. The areas under the receiver operating characteristic curves （ROC-AUC） were used to compare the diagnostic power of cancer detection by means of serum zinc, and free PSA/total PSA ratio （fit）. Results： The men with levels of serum zinc that ranged from 40 ng/mL-60 ng/mL, had an age-adjusted odds ratios（OR） of 5.0. A cutoff value of 100 gg/mL for-serum zinc concentration provided a sensitivity of 90.5 % and a specificity of 32.7 % in elevated PSA range, and a sensitivity of 93.3 % and specificity of 27.1% in gray zone, respectively. In the gray zone ranges of 4.1 ng/mL-10.0 ng/mL, the ROC-AUC for zinc was 73.0 % higher than 62.7 % of f/t PSA ratio and 56.7 % of total PSA. Conclusion： PCa displays a lower serum zinc concentration. The measurement of zinc levels improves PCa detection in the gray zone compared with the f/t PSA ratio and total PSA. （Asian J Androl 2005 Sep; 7： 323-328）     

Relationship between prostate specific antigen and indexes of prostate volume in Japanese men

PURPOSE: We determined the relationship between serum prostate specific antigen (PSA) and indexes of prostate volume in Japanese men, and compared that relationship with the one in white men. MATERIALS AND METHODS: Data on a clinical cohort of 535 Japanese men with at least moderate lower urinary tract symptoms (LUTS) and clinical benign prostatic hyperplasia were examined. PSA, and total and transition zone prostate volume were related to age and linear regression analyses were performed to analyze the relationship between PSA and volume indexes. RESULTS: The group of 535 men with a median age of 68 years had a median serum PSA of 1.5 ng/ml, and a median total and transition zone volume of 26.8 and 8.8 ml, respectively. PSA, total prostate volume and transition zone volume increased almost linearly with age. On univariate regression with age with each successive decade total prostate volume increased by 10.65% (95% CI 5.4 to 16.2), transition zone volume increased by 20.84% (95% CI 11.84 to 30.56) and the transition zone index increased by 3.1% (95% CI 1.66 to 4.57). On multivariate analysis the PSA-total prostate volume relationship was statistically independent of age. The study suggests that Japanese men might produce or release more PSA per unit prostate volume than white men. CONCLUSIONS: Japanese men with LUTS and clinical benign prostatic hyperplasia but no evidence of prostate cancer might produce and/or release more PSA per unit prostate volume than white men. To our knowledge the cutoffs for PSA and prostate volume to predict the response to LUTS therapy and the development of complications in Japanese men are unknown. Future studies in Japanese men are needed to identify these cutoffs.     

Relationship between prostate‐specific antigen and obesity in prostate cancer screening: Analysis of a large cohort in Japan

Previous studies have shown that lower prostate‐specific antigen (PSA) levels in obese men might decrease the sensitivity of prostate cancer screening, leading to delayed diagnosis and unfavorable prognosis. We examined whether the effect of obesity is important in prostate cancer screening of Japanese men, who have a low prevalence of obesity. We analyzed 19 294 male subjects from a large cohort of Toyota Motor Corporation (TMC) employees (aged >50 years, serum PSA level ≤4.0 ng/mL) who underwent physical examinations from August 2006 to December 2009. The relationship between PSA level and obesity‐related factors was analyzed by simple and multiple regression analysis. The relationships between six body mass index (BMI) categories, and PSA level and PSA mass (PSA concentration × plasma volume) were analyzed. PSA level decreased significantly with increasing BMI, but the coefficient of determination was very low. Mean PSA values decreased from 1.02 to 0.85 ng/mL as BMI increased from underweight (BMI <18.5) to morbidly obese (BMI >35). However, PSA mass peaked in the overweight category and was slightly reduced with increasing BMI. On multiple regression analysis, PSA level was influenced by age, diastolic blood pressure and high‐density lipoprotein as well as BMI. We found an inverse but weak relationship between PSA level and BMI. Obesity seems to have very limited influence on prostate cancer screening in this population. Nonetheless, when considering indications for prostatic biopsy in obese men, we should be aware that the hemodilution effect might reduce PSA levels.