Clinicopathological features of prostate cancer detected by transrectal ultrasonography-guided systematic six-sextant biopsy

An Automated Micro-Total Immunoassay System for Measuring Cancer-Associated α2,3-linked Sialyl N-Glycan-Carrying Prostate-Specific Antigen May Improve the Accuracy of Prostate Cancer Diagnosis

The low specificity of the prostate-specific antigen (PSA) for early detection of prostate cancer (PCa) is a major issue worldwide. The aim of this study to examine whether the serum PCa-associated α2,3-linked sialyl N-glycan-carrying PSA (S2,3PSA) ratio measured by automated micro-total immunoassay systems (μTAS system) can be applied as a diagnostic marker of PCa. The μTAS system can utilize affinity-based separation involving noncovalent interaction between the immunocomplex of S2,3PSA and Maackia amurensis lectin to simultaneously determine concentrations of free PSA and S2,3PSA. To validate quantitative performance, both recombinant S2,3PSA and benign-associated α2,6-linked sialyl N-glycan-carrying PSA (S2,6PSA) purified from culture supernatant of PSA cDNA transiently-transfected Chinese hamster ovary (CHO)-K1 cells were used as standard protein. Between 2007 and 2016, fifty patients with biopsy-proven PCa were pair-matched for age and PSA levels, with the same number of benign prostatic hyperplasia (BPH) patients used to validate the diagnostic performance of serum S2,3PSA ratio. A recombinant S2,3PSA- and S2,6PSA-spiked sample was clearly discriminated by μTAS system. Limit of detection of S2,3PSA was 0.05 ng/mL and coefficient variation was less than 3.1%. The area under the curve (AUC) for detection of PCa for the S2,3PSA ratio (%S2,3PSA) with cutoff value 43.85% (AUC; 0.8340) was much superior to total PSA (AUC; 0.5062) using validation sample set. Although the present results are preliminary, the newly developed μTAS platform for measuring %S2,3PSA can achieve the required assay performance specifications for use in the practical and clinical setting and may improve the accuracy of PCa diagnosis. Additional validation studies are warranted.

Prostate Biopsy Using Transrectal Ultrasonography; The Optimal Number of Cores Regarding Cancer Detection Rate and Complications

BACKGROUND

Transrectal ultrasound guided biopsy of the prostate is the most common modality used to diagnose prostate cancer.

OBJECTIVES

The aim of this study was to evaluate the optimal number of cores at prostate biopsy, which have the most diagnostic value with least adverse effects.

PATIENTS AND MATERIALS

Transrectal ultrasonography (TRUS) guided biopsy was performed in 180 patients suspicious for prostate cancer due to either abnormal rectal examination or elevated PSA. The patients were divided randomly into three groups of six-core, twelve-core and eighteen-core biopsies. The detection rate of prostate cancer in each group with the rate of post biopsy urinary infection and prostatitis were compared.

RESULTS

Prostate cancer was diagnosed in 8 (13.3%), 21 (35%) and 24 (40%) patients in six, twelve and eighteen core biopsy groups, respectively. Urinary tract infection and prostatitis occurred in 17 (28.3%), 23 (38.3%) and 35 (58.3%) patients in six, twelve and eighteen core biopsy groups, respectively. Considering the detection rate of prostate cancer, there was a significant difference between 6 and 12 core biopsy groups (P = 0.006) and 12-core biopsies detected more cases of prostate cancer, but there was no significant difference between 12 and 18 core biopsy groups (P = 0.572). Considering the infection rate, there was no significant difference between 6 and 12 core biopsy groups (P = 0.254), but there was a significant difference between 12 and 18 core biopsy groups (P = 0.028) and infectious complications occurred more frequently in 18-core biopsy group.

CONCLUSIONS

The best balance between detection rate of prostate cancer and infectious complications of biopsies achieved in twelve-core biopsy protocol. Twelve-core biopsy enhances the rate of prostate cancer detection with minimum adverse effects.

Reproducibility, performance, and clinical utility of a genetic risk prediction model for prostate cancer in Japanese

Prostate specific antigen (PSA) is widely used as a diagnostic biomarker for prostate cancer (PC). However, due to its low predictive performance, many patients without PC suffer from the harms of unnecessary prostate needle biopsies. The present study aims to evaluate the reproducibility and performance of a genetic risk prediction model in Japanese and estimate its utility as a diagnostic biomarker in a clinical scenario. We created a logistic regression model incorporating 16 SNPs that were significantly associated with PC in a genome-wide association study of Japanese population using 689 cases and 749 male controls. The model was validated by two independent sets of Japanese samples comprising 3,294 cases and 6,281 male controls. The areas under curve (AUC) of the model were 0.679, 0.655, and 0.661 for the samples used to create the model and those used for validation. The AUCs were not significantly altered in samples with PSA 1-10 ng/ml. 24.2% and 9.7% of the patients had odds ratio <0.5 (low risk) or >2 (high risk) in the model. Assuming the overall positive rate of prostate needle biopsies to be 20%, the positive biopsy rates were 10.7% and 42.4% for the low and high genetic risk groups respectively. Our genetic risk prediction model for PC was highly reproducible, and its predictive performance was not influenced by PSA. The model could have a potential to affect clinical decision when it is applied to patients with gray-zone PSA, which should be confirmed in future clinical studies.

Prostate cancer imaging: what surgeons, radiation oncologists, and medical oncologists want to know

OBJECTIVE

The purpose of this article is to discuss the information that is important to note in imaging reports of patients with prostate cancer.

CONCLUSION

Accurate staging through imaging is an integral part of prostate cancer management. Ultrasound, CT, bone scanning, and MRI are used for prostate cancer patients to assess the primary tumor, lymph node status, and bone metastasis. Accurate reporting of images is crucial for effective cancer treatment.

[Clinical value of diffusion-weighted magnetic resonance imaging for localization of prostate cancer--comparison with the step sections of radical prostatectomy]

PURPOSE

The objective of our study was to compare T2-weighted magnetic resonance imaging (T2WI), combined T2-weighted and dynamic imaging (Dynamic), and combined T2-weighted and diffusion-weighted imaging (DWI) in the identification of the site of prostate cancer.

MATERIALS AND METHODS

Before radical prostatectomy, 85 patients with prostate cancer underwent magnetic resonance imaging using a 1.5-T endorectal coil; we excluded 3 patients treated with neoadjuvant hormonal therapy. The sites of prostate cancer in 82 patients were predicted by T2WI alone, T2WI + Dynamic, and T2WI + DWI, and the results were compared with the step-section analysis of radical prostatectomy specimens. The peripheral zone (PZ) and the transition zone (TZ) of the prostate were divided into left and right halves. Only tumors with a diameter of more than 5 mm were considered significant.

RESULTS

The sensitivity, specificity, positive predictive value (PPV), and the area under the receiver operating characteristic (ROC) curve (Az) for the prediction of the site of prostate cancer in the PZ of the prostate were as follows: 42%, 94%, 93%, and 0.76 for T2WI alone; 48%, 96%, 96%, and 0.78 for T2WI + Dynamic; and 50%, 96%, 96%, and 0.81 for T2WI + DWI. The sensitivity, specificity, PPV, and Az for the prediction of the site of prostate cancer in the TZ of the prostate were as follows: 31%, 92%, 76%, and 0.66 for T2WI alone; 46%, 82%, 67%, and 0.65 for T2WI + Dynamic; and 48%, 94%, 85%, and 0.71 for T2WI + DWI.

CONCLUSION

The Az value for the prediction of prostate cancer in the PZ and those in the TZ of the prostate was the highest for the combined T2WI and DWI approach.

Contemporary impact of transrectal ultrasound lesions for prostate cancer detection

PURPOSE

Transrectal ultrasound (TRUS) guided systematic biopsy of the prostate is the gold standard diagnostic modality for prostate cancer. Consequently, the value of discrete hypoechoic lesions on TRUS lesions considered suspicious for cancer deserves meticulous reevaluation, specifically in the prostate specific antigen era when the majority of tumors diagnosed are nonpalpable. We studied whether the predictability of a biopsy core changes if the tissue comes from an isoechoic vs hypoechoic lesion.

MATERIALS AND METHODS

Prospective data were collected on 3,912 consecutive patients referred to our medical center between 1993 and 1999 for biopsy of the prostate. A sextant technique (apex, mid gland and base) with an additional core biopsy from the transitional zone was used. If a hypoechoic lesion was identified, the biopsy was taken from the lesion. Correlation between hypoechoic lesions, isoechoic areas and cancer detection for each core was performed.

RESULTS

A total of 31,296 cores were obtained from the cohort. Overall 2,642 (68%) cores had at least 1 hypoechoic lesion ultrasonographically. Cancer was detected in 675 (25.5%) and 323 (25.4%) patients with or without hypoechoic lesions (p = 0.97). The per core cancer detection was fairly uniform and averaged 9.3% and 10.4% for hypoechoic and isoechoic areas, respectively. The difference was not statistically significant (p = 0.3). Gleason scores were less than 7, 7 and greater than 7 in 46%, 34% and 20% of cases, respectively.

CONCLUSIONS

Despite the higher prevalence of cancers discovered in prostates with hypoechoic areas, the hypoechoic lesion itself was not associated with increased cancer prevalence compared with biopsy cores from isoechoic areas. For impalpable tumors TRUS findings are not contributory for staging.

Free/total PSA ratio is a powerful predictor of future prostate cancer morbidity in men with initial PSA levels of 4.1 to 10.0 ng/mL

OBJECTIVES

To evaluate the usefulness of measuring the free/total prostate-specific antigen (PSA) ratio (%fPSA) in men with initial PSA levels of 4.1 to 10.0 ng/mL as a predictor of the future risk of developing prostate cancer.

METHODS

Between 1989 and 2001, 201 subjects with an initial PSA level of 4.1 to 10.0 ng/mL, who had free PSA measured at initial screening using frozen serum and underwent consecutive screening at least once, were enrolled in this study. All participants were followed up by consecutive PSA measurements. Biopsies were performed for those with PSA levels greater than 10.0 ng/mL or with a PSA velocity of 1.0 ng/mL or greater in consecutive screening. The follow-up period was 1 to 12 years, and the mean number of screenings was 3.8. The usefulness of %fPSA, age, and total PSA as predictive factors of future prostate cancer morbidity was investigated. The cumulative non-prostate cancer rate was evaluated using Kaplan-Meier analysis relative to various %fPSA cutoffs.

RESULTS

A total of 142 patients (71%) underwent prostate biopsy at least once during observation according to the biopsy criteria. The detection rate of prostate cancer was 26% (53 of 201) in consecutive screening. The most recent PSA velocity and serum PSA levels at last follow-up in patients with prostate cancer were significantly higher than in those without prostate cancer. The cumulative non-prostate cancer rate was significantly greater in subjects with %fPSA less than the cutoff than in those with %fPSA at the cutoff point or greater in the %fPSA cutoffs of 16% to 25%.

CONCLUSIONS

Men with PSA levels of 4.1 to 10 ng/mL who are not suspected of having prostate cancer by whatever means should undergo %fPSA measurement and be carefully monitored at short intervals over the long-term if they have lower %fPSA levels.

The diagnostic accuracy of the age-adjusted and prostate volume-adjusted biopsy method in males with prostate specific antigen levels of 4.1-10.0 ng/mL

BACKGROUND

The authors evaluated a new age-adjusted and prostate volume-adjusted biopsy method for the detection of prostate carcinoma through the transperineal and the transrectal approaches in men with PSA levels of 4.1-10.0 ng/mL.

METHODS

The value of the adjusted biopsy method was calculated by using the following four factors: 1) life expectancy in Japanese men in 1998, 2) prostate volume estimated by transrectal ultrasonography, 3) tumor doubling time (4 years), and 4) tumor volume that influenced death (20 cc). The number of biopsy sites was set at 8-20. Between August, 1999 and December, 2001, 100 men age <or= 79 years with prostate specific antigen (PSA) levels of 4.1-10.0 ng/mL underwent age-adjusted and volume-adjusted, systematic prostate biopsy.

RESULTS

The detection rate for the adjusted biopsy method was 46% (46 of 100 men). The clinical stage of prostate carcinoma was Stage II in 85% of patients and Stage III in 15% of patients. If routine six-sextant biopsy had been performed in all of the men who underwent adjusted systematic biopsy, then 15 of 46 patients (33%) with prostate carcinoma would have been missed. The detection rates of prostate carcinoma in men who underwent adjusted biopsies were relatively high, especially in men with PSA levels of 6.1-10.0 ng/mL, men age <or= 64 years, men with prostate volumes >or= 50 cc, and men with PSA density (PSAD) levels <or= 0.15 ng/mL/cc compared with the detection rates from six-sextant and directed biopsies. The high detection rates were observed from biopsy sites at the posterior aspect of the lateral lobe through both the transperineal approach and the transrectal approach and at the anterior aspect of the transition zone through the transperineal approach.

CONCLUSIONS

The age-adjusted and prostate volume-adjusted prostate biopsy method was more useful for detecting clinically significant disease compared with the traditional six-sextant biopsy method. This adjusted biopsy method was especially useful in patients age <or= 64 years, patients with large prostate volumes (>/= 50 cc), and patients with PSAD levels <or= 0.15 ng/mL/cc. The authors recommend that patients undergo an additional transition zone biopsy at the anterior aspect through the transperineal approach.

Correlation of prostate-specific antigen before prostate cancer detection and clinicopathologic features: evaluation of mass screening populations

OBJECTIVES

Although prostate-specific antigen (PSA) has become the reference standard for prostate cancer diagnosis, few reports have examined the long-term changes in PSA values before the diagnosis of prostate cancer in a large number of subjects. We investigated serial PSA levels and related values before prostate cancer diagnosis in a mass screening population and analyzed the values in an attempt to discover some values useful in clinical diagnostic science.

METHODS

We performed mass screening for prostate cancer in 9671 subjects from 1986 to 1998. The initial screening method was measurement of prostatic acid phosphatase from 1986 to 1991 and measurement of PSA from 1992 to 1998. As a result, 303 cases of prostate cancer were diagnosed. For all the cases diagnosed before 1991, we measured the serum PSA value in preserved frozen serum.

RESULTS

The prostate cancer detection rate was 3.1% among all subjects observed during the 13-year period. By measurement of the PSA level using frozen serum during the pre-PSA era, we found that 62% of patients demonstrated a PSA abnormality for more than 1 year (average 2.8) before prostate cancer diagnosis. Prostate cancer that was diagnosed within 1 year after a PSA value became abnormal was not associated with bone metastasis. Concerning the relationship between PSA velocity (PSAV) and clinical stage, the proportion of Stage B cancer was 86% in the subjects whose PSAV level before diagnosis was 0.18 ng/mL/yr or less and it was only 29% in those with PSAV levels of 4.5 ng/mL/yr or more. Only 3 (3.5%) of 86 patients with prostate cancer with PSAV levels of 4.4 ng/mL/yr or less had bone metastasis, and 2 of those 3 patients had poorly differentiated adenocarcinoma.

CONCLUSIONS

Although a total of 62% of patients had an abnormal PSA level more than 1 year before prostate cancer diagnosis, no patients with prostate cancer who were diagnosed within 1 year after the PSA level became abnormal had bone metastasis. Among patients who have undergone mass screening twice or more, a clinically useful indicator of the lack of bone metastasis would be a period between the detection of PSA levels of 4.1 ng/mL or more but not more than 10 ng/mL and prostate cancer diagnosis of less than 1 year and a diagnosis of well or moderately differentiated adenocarcinoma or a PSAV of 4.4 ng/mL/yr or less and a cancer diagnosis of well or moderately differentiated adenocarcinoma.