Update on the Appropriate Staging Evaluation for Newly Diagnosed Prostate Cancer

A peptide-centric approach to analyse quantitative proteomics data- an application to prostate cancer biomarker discovery

Bottom-up proteomics is a popular approach in molecular biomarker research. However, protein analysts have realized the limitations of protein-based approaches for identifying and quantifying proteins in complex samples, such as the identification of peptides sequences shared by multiple proteins and the difficulty in identifying modified peptides. Thus, there are many exciting opportunities to improve analysis methods. Here, an alternative method focused on peptide analysis is proposed as a complement to the conventional proteomics data analysis. To investigate this hypothesis, a peptide-centric approach was applied to reanalyse a urine proteome dataset of samples from prostate cancer patients and controls. The results were compared with the conventional protein-centric approach. The relevant proteins/peptides to discriminate the groups were detected based on two approaches, p-value and VIP values obtained by a PLS-DA model. A comparison of the two strategies revealed high inconsistency between protein and peptide information and greater involvement of peptides in key PCa processes. This peptide analysis unveiled discriminative features that are lost when proteins are analyzed as homogeneous entities. This type of analysis is innovative in PCa and integrated with the widely used protein-centric approach might provide a more comprehensive view of this disease and revolutionize biomarker discovery. SIGNIFICANCE: In this study, the application of a protein and peptide-centric approaches to reanalyse a urine proteome dataset from prostate cancer (PCa) patients and controls showed that many relevant proteins/peptides are missed by the conservative nature of p-value in statistical tests, therefore, the inclusion of variable selection methods in the analysis of the dataset reported in this work is fruitful. Comparison of protein- and peptide-based approaches revealed a high inconsistency between protein and peptide information and a greater involvement of peptides in key PCa processes. These results provide a new perspective to analyse proteomics data and detect relevant targets based on the integration of peptide and protein information. This data integration allows to unravel discriminative features that normally go unnoticed, to have a more comprehensive view of the disease pathophysiology and to open new avenues for the discovery of biomarkers.

Prostate Cancer Biomarkers: From diagnosis to prognosis and precision-guided therapeutics

Prostate cancer (PCa) is one of the most commonly diagnosed malignancies and among the leading causes of cancer-related death worldwide. It is a highly heterogeneous disease, ranging from remarkably slow progression or inertia to highly aggressive and fatal disease. As therapeutic decision-making, clinical trial design and outcome highly depend on the appropriate stratification of patients to risk groups, it is imperative to differentiate between benign versus more aggressive states. The incorporation of clinically valuable prognostic and predictive biomarkers is also potentially amenable in this process, in the timely prevention of metastatic disease and in the decision for therapy selection. This review summarizes the progress that has so far been made in the identification of the genomic events that can be used for the classification, prediction and prognostication of PCa, and as major targets for clinical intervention. We include an extensive list of emerging biomarkers for which there is enough preclinical evidence to suggest that they may constitute crucial targets for achieving significant advances in the management of the disease. Finally, we highlight the main challenges that are associated with the identification of clinically significant PCa biomarkers and recommend possible ways to overcome such limitations.

Diagnostic Value of CT in Detecting Peripheral Zone Prostate Cancer

OBJECTIVE. The purpose of this study was to identify the sensitivity of contrast-enhanced CT in detecting high-grade prostate adenocarcinoma. MATERIALS AND METHODS. A retrospective analysis included 100 patients with prostate cancer proven by biopsy between January 2010 and December 2017 who underwent staging CT of the abdomen and pelvis within 3 months of diagnosis. The control subjects were 100 randomly selected aged-matched male outpatients with no known history of malignancy who underwent contrast-enhanced CT of the abdomen and pelvis in the same time period as the patients with cancer. Two readers, blinded to both groups, independently assessed the likelihood of prostate cancer on the basis of the CT finding of focal abnormally increased peripheral enhancement in the prostate. Binary classification of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) was used to assess the diagnostic utility of CT versus the reference standard of transrectal ultrasound-guided biopsy. RESULTS. Eighty-three of 100 patients with biopsy-proven prostate cancer and 92 of 100 control subjects were correctly identified (sensitivity, 0.83; specificity, 0.92; PPV, 0.91; NPV, 0.84). There was no significant difference in diagnostic accuracy among subjects with different Gleason scores. Interrater agreement on both the cancer and control patients was 0.76 as assessed by Cohen kappa statistic. CONCLUSION. Incidental detection of a focal area of increased enhancement in the periphery of the prostate at contrast-enhanced CT may represent a clinically significant cancer and deserves further workup with prostate-specific antigen measurement and correlation with clinical risk factors for prostate cancer.

A qualitative study to understand guideline-discordant use of imaging to stage incident prostate cancer

Background

Approximately half of veterans with low-risk prostate cancer receive guideline-discordant imaging. Our objective was to identify and describe (1) physician knowledge, attitudes, and practices related to the use of imaging to stage prostate cancer, (2) patient attitudes and behaviors related to use of imaging, and (3) to compare responses across three VA medical centers (VAMCs).

Methods

A qualitative approach was used to explore patient and provider knowledge and behaviors relating to the use of imaging. We conducted 39 semi-structured interviews total—including 22 interviews with patients with newly diagnosed with prostate cancer and 17 interviews with physicians caring for them—between September 2014 and July 2015 at three VAMCs representing a spectrum of inappropriate imaging rates. After core theoretical concepts were identified, the Theoretical Domains Framework (TDF) was selected to explore linkages between themes within the dataset and existing domains within the framework. Interviews were audio-recorded, transcribed verbatim, and then coded and analyzed using Nvivo software.

Results

Themes from patient interviews were categorized within four TDF domains. Patients reported little interest in staging as compared to disease treatment (goals), and many could not remember if they had imaging at all (knowledge). Patients tended to trust their doctor to make decisions about appropriate tests (beliefs about capabilities). Some patients expressed a minor concern for radiation exposure, but anxiety about cancer outcomes outweighed these fears (emotion). Themes from physician interviews were categorized within five TDF domains. Most physicians self-reported that they know and trust imaging guidelines (knowledge) yet some were still likely to follow their own intuition, whether due to clinical suspicion or years of experience (beliefs about capabilities). Additionally, physicians reported that medico-legal concerns, fear of missing associated diagnoses (beliefs about consequences), influence from colleagues who image frequently (social influences), and the facility where they practice influences rates of imaging (environmental context).

Conclusions

Interviews with patients and physicians suggest that physicians are the primary (and in some cases only) decision-makers regarding staging imaging for prostate cancer. This finding suggests a physician-targeted intervention may be the most effective strategy to improve guideline-concordant prostate cancer imaging.

Mass-like peripheral zone enhancement on CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer

PURPOSE

To determine whether focal peripheral zone enhancement on routine venous-phase CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

MATERIALS AND METHODS

IRB approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Forty-three patients with higher-grade prostate cancer (≥Gleason 4 + 3) and 96 with histology-confirmed lower-grade (≤Gleason 3 + 4 [n = 47]) or absent (n = 49) prostate cancer imaged with venous-phase CT comprised the study population. CT images were reviewed by ten blinded radiologists (5 attendings, 5 residents) who scored peripheral zone enhancement on a scale of 1 (benign) to 5 (malignant). Mass-like peripheral zone enhancement was considered malignant. Likelihood ratios (LR) and specificities were calculated. Multivariate conditional logistic regression analyses were conducted.

RESULTS

Scores of "5" were strongly predictive of higher-grade prostate cancer (pooled LR+ 9.6 [95% CI 5.8-15.8]) with rare false positives (pooled specificity: 0.98 [942/960, 95% CI 0.98-0.99]; all 10 readers had specificity ≥95%). Attending scores of "5" were more predictive than resident scores of "5" (LR+: 14.7 [95% CI 5.8-37.2] vs. 7.6 [95% CI 4.2-13.7]) with similar specificity (0.99 [475/480, 95% CI 0.98-1.00] vs. 0.97 [467/480, 95% CI 0.96-0.99]). Significant predictors of an assigned score of "5" included presence of a peripheral zone mass (p < 0.0001), larger size (p < 0.0001), and less reader experience (p = 0.0008). Significant predictors of higher-grade prostate cancer included presence of a peripheral zone mass (p = 0.0002) and larger size (p < 0.0001).

CONCLUSION

Focal mass-like peripheral zone enhancement on routine venous-phase CT is specific and predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

Altered glycosylation in prostate cancer

Prostate cancer is annually the most common newly diagnosed cancer in men. The prostate functions as a major secretory gland for the production of glycoproteins critical to sperm activation and reproduction. Prostate-specific antigen (PSA), produced by the prostate, is one of the most commonly assayed glycoproteins in blood, serving as a biomarker for early detection and progression of prostate cancer. The single site of N-glycosylation on PSA has been the target of multiple glycan characterization studies. In this review, the extensive number of studies that have characterized the changes in O-linked and N-linked glycosylations associated with prostate cancer development and progression will be summarized. This includes analysis of the glycosylation of PSA, and other prostate glycoproteins, in tissues, clinical biofluids, and cell line models. Other studies are summarized in the context of understanding the complexities of these glycan changes in order to address the many confounding questions associated with prostate cancer, as well as efforts to improve prostate cancer biomarker assays using targeted glycomic-based strategies.

Updated trends in imaging use in men diagnosed with prostate cancer

BACKGROUND

Previous studies have found persistent overuse of imaging for clinical staging of men with low-risk prostate cancer. We aimed to determine imaging trends in three cohorts of men.

METHODS

We analyzed imaging trends of men with prostate cancer who were a part of Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) (1998-2006), were insured by Medicare (1998-2006), or privately insured (Ingenix database, 2002-2006). The rates of computed tomography (CT), magnetic resonance imaging (MRI) and bone scan (BS) were determined and time trends were analyzed by linear regression. For men in CaPSURE, demographic and clinical predictors of test use were explored using a multivariable regression model.

RESULTS

Since 1998, there was a significant downward trend in BS (16%) use in the CaPSURE cohort (N=5156). There were slight downward trends (2.4 and 1.7%, respectively) in the use of CT and MRI. Among 54 322 Medicare patients, BS, CT and MRI use increased by 2.1, 10.8 and 2.2% and among 16 161 privately insured patients, use increased by 7.9, 8.9 and 3.7%, respectively. In CaPSURE, the use of any imaging test was greater in men with higher-risk disease. In addition, type of insurance and treatment affected the use of imaging tests in this population.

CONCLUSIONS

There is widespread misuse of imaging tests in men with low-risk prostate cancer, particularly for CT. These findings highlight the need for examination of factors that drive decision making with respect to imaging in this setting.

Prostate cancer imaging trends after a nationwide effort to discourage inappropriate prostate cancer imaging

BACKGROUND

Reducing inappropriate use of imaging to stage incident prostate cancer is a challenging problem highlighted recently as a Physician Quality Reporting System quality measure and by the American Society of Clinical Oncology and the American Urological Association in the Choosing Wisely campaign. Since 2000, the National Prostate Cancer Register (NPCR) of Sweden has led an effort to decrease national rates of inappropriate prostate cancer imaging by disseminating utilization data along with the latest imaging guidelines to urologists in Sweden. We sought to determine the temporal and regional effects of this effort on prostate cancer imaging rates.

METHODS

We performed a retrospective cohort study among men diagnosed with prostate cancer from the NPCR from 1998 to 2009 (n = 99 879). We analyzed imaging use over time stratified by clinical risk category (low, intermediate, high) and geographic region. Generalized linear models with a logit link were used to test for time trend.

RESULTS

Thirty-six percent of men underwent imaging within 6 months of prostate cancer diagnosis. Overall, imaging use decreased over time, particularly in the low-risk category, among whom the imaging rate decreased from 45% to 3% (P < .001), but also in the high-risk category, among whom the rate decreased from 63% to 47% (P < .001). Despite substantial regional variation, all regions experienced clinically and statistically (P < .001) significant decreases in prostate cancer imaging.

CONCLUSIONS

A Swedish effort to provide data on prostate cancer imaging use and imaging guidelines to clinicians was associated with a reduction in inappropriate imaging over a 10-year period, as well as slightly decreased appropriate imaging in high-risk patients. These results may inform current efforts to promote guideline-concordant imaging in the United States and internationally.

Appropriate and inappropriate imaging rates for prostate cancer go hand in hand by region, as if set by thermostat

Policy makers interested in containing health care costs are targeting regional variation in utilization, including the use of advanced imaging. However, bluntly decreasing utilization among the highest-utilization regions may have negative consequences. In a cross-sectional study of prostate cancer patients from 2004 to 2005, we found that regions with lower rates of inappropriate imaging also had lower rates of appropriate imaging. Similarly, regions with higher overall imaging rates tended to have not only higher rates of inappropriate imaging, but also higher rates of appropriate imaging. In fact, men with high-risk prostate cancer were more likely to receive appropriate imaging if they resided in areas with higher rates of inappropriate imaging. This "thermostat model" of regional health care utilization suggests that poorly designed policies aimed at reducing inappropriate imaging could limit access to appropriate imaging for high-risk patients. Health care organizations need clearly defined quality metrics and supportive systems to encourage appropriate treatment for patients and to ensure that cost containment does not occur at the expense of quality.

Imaging in prostate cancer staging: present role and future perspectives

Despite recent improvements in detection and treatment, prostate cancer continues to be the most common malignancy and the second leading cause of cancer-related mortality. Thus, although survival rate continues to improve, prostate cancer remains a compelling medical health problem. The major goal of prostate cancer imaging in the next decade will be more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information in order to plan the most appropriate therapeutic strategy. No consensus exists regarding the use of imaging for evaluating primary prostate cancer. However, conventional and functional imaging are expanding their role in detection and local staging and, moreover, functional imaging is becoming of great importance in oncologic management and monitoring of therapy response. This review presents a multidisciplinary perspective on the role of conventional and functional imaging methods in prostate cancer staging.

The population level prevalence and correlates of appropriate and inappropriate imaging to stage incident prostate cancer in the medicare population

PURPOSE

According to guidelines most men with incident prostate cancer do not require staging imaging. We determined the population level prevalence and correlates of appropriate and inappropriate imaging in this cohort.

MATERIALS AND METHODS

We performed a cross-sectional study of men 66 to 85 years old who were diagnosed with prostate cancer in 2004 and 2005 from the SEER (Surveillance, Epidemiology and End Results)-Medicare database. Low risk (no prostate specific antigen greater than 10 ng/ml, Gleason score greater than 7 or clinical stage greater than T2) and high risk (1 or more of those features) groups were formed. Inappropriate imaging was defined as any imaging for men at low risk and appropriate imaging was defined as bone scan for men at high risk as well as pelvic imaging as appropriate. Logistic regression modeled imaging in each group.

RESULTS

Of 18,491 men at low risk 45% received inappropriate imaging while only 66% of 10,562 at high risk received appropriate imaging. For patients at low risk inappropriate imaging was associated with increasing clinical stage (T2 vs T1 OR 1.35, 95% CI 1.27-1.44), higher Gleason score (7 vs less than 7 OR 1.80, 95% CI 1.69-1.92), increasing age and comorbidity as well as decreasing education. Appropriate imaging for men at high risk was associated with lower stage (T4, T3 and T2 vs T1 OR 0.63, 95% CI 0.48-0.82, OR 0.67, 95% CI 0.60-0.80 and OR 0.87, 95% CI 0.80-0.86) and with higher Gleason score (greater than 8 and 7 vs less than 7 OR 2.18, 95% CI 1.92-2.48 and 1.51, 95% CI 1.35-1.70, respectively) as well as with younger age, white race, higher income, lower stage and more comorbidity.

CONCLUSIONS

We found poor adherence to imaging guidelines for men with incident prostate cancer. Understanding the patterns by which clinicians use imaging for prostate cancer should guide educational efforts as well as research to suggest evidence-based guideline improvements.

Bone scan overuse in staging of prostate cancer: an analysis of a Veterans Affairs cohort

OBJECTIVES

To determine the use and subsequent yield of bone scan imaging in a contemporary Veterans Affairs (VA) cohort of men with prostate cancer. With contemporary widespread prostate-specific antigen (PSA) screening, more patients are being diagnosed with low- and intermediate-risk prostate cancer, reducing the need and yield of bone scan imaging.

METHODS

We retrospectively reviewed the charts of 1598 men diagnosed with prostate cancer from 1998 to 2004 at the Greater Los Angeles and Long Beach VA Medical Centers. We used univariate and multivariate analyses to measure the association between patient (age, race, and comorbidities) and tumor (PSA, clinical stage, Gleason grade) characteristics with bone scan use and subsequent positivity. We conducted the analysis for scans for the entire cohort and those with low and high risk of metastatic disease.

RESULTS

Of 519 men with low-risk disease, 132 (25%) underwent bone scan imaging, none with positive findings. On multivariate analysis for the entire cohort, younger age, Long Beach VA site, increasing PSA level (≥10 ng/mL), clinical stage (cT2 or greater), and Gleason score (≥7) were all positively associated with bone scan use; however, only PSA level ≥20 ng/mL, clinical stage cT3 or greater, and Gleason score ≥4 + 3 corresponded with positivity. A bone scan positivity rate of ≥10% was limited to men with clinical stage cT3 or greater, Gleason score of ≥8, or PSA level of ≥20 ng/mL.

CONCLUSIONS

Although decreasing in incidence with time, our results demonstrate extensive overuse of bone scan imaging among VA patients with low-risk prostate cancer. These patterns of overuse for men with low-risk cancer, yielding no positive findings, result in unnecessary patient anxiety and significant economic waste for the VA Healthcare System.

Overuse of imaging for staging low risk prostate cancer

PURPOSE

Routine imaging for staging low risk prostate cancer is not recommended according to current guidelines. We characterized patterns of care and factors associated with imaging overuse.

MATERIALS AND METHODS

We used SEER-Medicare linked data to identify men diagnosed with low risk prostate cancer from 2004 to 2005, and determined if imaging (computerized tomography, magnetic resonance imaging, bone scan, abdominal ultrasound) was obtained following prostate cancer diagnosis before treatment.

RESULTS

Of the 6,444 men identified with low risk disease 2,330 (36.2%) underwent imaging studies. Of these men 1,512 (23.5%), 1,710 (26.5%) and 118 (1.8%) underwent cross-sectional imaging (computerized tomography or magnetic resonance imaging), bone scan and abdominal ultrasound, respectively. Radiation therapy vs surgery was associated with greater odds of imaging (OR 1.99, 95% CI 1.68-2.35, p <0.01), while active surveillance vs surgery was associated with lower odds of imaging (OR 0.44, 95% CI 0.34-0.56, p <0.01). Associated with increased odds of imaging was median household income greater than $60,000 (OR 1.41, 95% CI 1.11-1.79, p <0.01), and men from New Jersey vs San Francisco (OR 3.11, 95% CI 2.24-4.33, p <0.01) experienced greater odds of imaging. Men living in areas with greater than 90% vs less than 75% high school education experienced lower odds of imaging (OR 0.76, 95% CI 0.6-0.95, p = 0.02).

CONCLUSIONS

There is widespread overuse and significant geographic variation in the use of imaging to stage low risk prostate cancer. Moreover treatment associated variation in imaging was noted with the greatest vs lowest imaging use observed for radiation therapy vs active surveillance.

Development of a real-time clinical decision support system upon the Web MVC-based architecture for prostate cancer treatment

BACKGROUND

A real-time clinical decision support system (RTCDSS) with interactive diagrams enables clinicians to instantly and efficiently track patients' clinical records (PCRs) and improve their quality of clinical care. We propose a RTCDSS to process online clinical informatics from multiple databases for clinical decision making in the treatment of prostate cancer based on Web Model-View-Controller (MVC) architecture, by which the system can easily be adapted to different diseases and applications.

METHODS

We designed a framework upon the Web MVC-based architecture in which the reusable and extractable models can be conveniently adapted to other hospital information systems and which allows for efficient database integration. Then, we determined the clinical variables of the prostate cancer treatment based on participating clinicians' opinions and developed a computational model to determine the pretreatment parameters. Furthermore, the components of the RTCDSS integrated PCRs and decision factors for real-time analysis to provide evidence-based diagrams upon the clinician-oriented interface for visualization of treatment guidance and health risk assessment.

RESULTS

The resulting system can improve quality of clinical treatment by allowing clinicians to concurrently analyze and evaluate the clinical markers of prostate cancer patients with instantaneous clinical data and evidence-based diagrams which can automatically identify pretreatment parameters. Moreover, the proposed RTCDSS can aid interactions between patients and clinicians.

CONCLUSIONS

Our proposed framework supports online clinical informatics, evaluates treatment risks, offers interactive guidance, and provides real-time reference for decision making in the treatment of prostate cancer. The developed clinician-oriented interface can assist clinicians in conveniently presenting evidence-based information to patients and can be readily adapted to an existing hospital information system and be easily applied in other chronic diseases.

Radionuclide and hybrid imaging of recurrent prostate cancer

Prostate cancer is one of the most common cancers in men, leading to substantial morbidity and mortality. After definitive therapy with surgery or radiation, many patients have biochemical relapse of disease--ie, an increase in their prostate-specific antigen level--which often precedes clinically apparent disease by months or even years. Therefore, imaging of the site and extent of tumour recurrence (local, regional, distant, or a combination) is of great interest. Conventional morphological imaging methods showed limited accuracy for assessment of recurrent prostate cancer; however, in recent years, functional and molecular imaging have offered the possibility of imaging molecular or cellular processes of individual tumours, often with more accuracy than morphological imaging. Hybrid imaging modalities (PET-CT, and single-photon emission CT [SPECT]-CT) have been introduced that combine functional and morphological data and allow whole-body imaging. Here, we review the contribution of radionuclide imaging and hybrid imaging for assessment of recurrent prostate cancer (local vs regional vs distant disease). We discuss available data on PET-CT and SPECT-CT, and provide an overview of experimental tracers and their preclinical and clinical development. Finally, we present a perspective on the potential of future hybrid magnetic resonance-PET imaging.

Modalities for imaging of prostate cancer

Prostate cancer is the second most common cause of cancer deaths among males in the United States. Prostate screening by digital rectal examination and prostate-specific antigen has shifted the diagnosis of prostate cancer to lower grade, organ confined disease, adding to overdetection and overtreatment of prostate cancer. The new challenge is in differentiating clinically relevant tumors from ones that may otherwise never have become evident if not for screening. The rapid evolution of imaging modalities and the synthesis of anatomic, functional, and molecular data allow for improved detection and characterization of prostate cancer. However, the appropriate use of imaging is difficult to define, as many controversial studies regarding each of the modalities and their utilities can be found in the literature. Clinical practice patterns have been slow to adopt many of these advances as a result. This review discusses the more established imaging techniques, including Ultrasonography, Magnetic Resonance Imaging, MR Spectroscopy, Computed Tomography, and Positron Emission Tomography. We also review several promising techniques on the horizon, including Dynamic Contrast-Enhanced MRI, Diffuse-Weighted Imaging, Superparamagnetic Nanoparticles, and Radionuclide Scintigraphy.

CT, MRI and ultrasound scanning rates: evaluation of cancer diagnosis, staging and surveillance in Ontario

OBJECTIVE

To examine practice patterns and rates of computed tomography (CT), magnetic resonance imaging (MRI), and abdominal ultrasound (AUS) during staging, treatment and surveillance for cancer patients.

METHODS

Using Ontario Health Insurance Plan billing data linked to the Ontario Cancer Registry, we determined rates of CT, MRI, and AUS by body site for breast, colorectal, lung, lymphoma, and prostate cancer, from 1998 to 2002. Rates of scans were additionally examined by region of patient residence and time from cancer diagnosis.

RESULTS

The frequency of imaging increased in nearly all scans and tumors over the study period. Rates of peri-diagnosis scans varied substantially by region, ranging from 1.7-fold variation (CT for lung cancer) to 50-fold variation (MRI for breast cancer). For breast cancer, there is possible over-utilization of CT, but overall rates of scanning appear reasonable for the other four cancers.

CONCLUSIONS

Considerable regional variation in imaging rates suggests utilization guidelines should be developed or knowledge transfer initiatives are needed to improve compliance to existing guidelines. In breast cancer, there appears to be over-utilization of imaging. Further studies are necessary to determine utilization for each stage, the reason scans were obtained, and the impact of scans on patient outcomes.

Optimal cost-effective staging evaluations in prostate cancer

A new diagnosis of prostate cancer presents to both the patient and physician questions regarding the best approach for further assessing the extent of disease prior to selecting a treatment strategy. In addition to the initial clinical data such as serum prostate-specific antigen level, findings on digital rectal examination, and core biopsy Gleason score, several procedures and imaging modalities are available to further stage newly diagnosed prostate cancer. A substantial percentage of the cost of managing prostate cancer is directly related to staging evaluations. Often, staging evaluations are performed that have limited test performance characteristics, subject the patient to unnecessary morbidity, or simply do not provide additional useful clinical information. It is important that the physician be familiar with the indications for the available staging modalities as well as the test performance characteristics in order to proceed appropriately and in an economically judicious fashion. This paper reviews the literature on this topic and summarizes previous experiences with procedures and imaging modalities for staging newly diagnosed prostate cancer.

Imaging prostate cancer: a multidisciplinary perspective

The major goal for prostate cancer imaging in the next decade is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. No consensus exists regarding the use of imaging for evaluating primary prostate cancers. Ultrasonography is mainly used for biopsy guidance and brachytherapy seed placement. Endorectal magnetic resonance (MR) imaging is helpful for evaluating local tumor extent, and MR spectroscopic imaging can improve this evaluation while providing information about tumor aggressiveness. MR imaging with superparamagnetic nanoparticles has high sensitivity and specificity in depicting lymph node metastases, but guidelines have not yet been developed for its use, which remains restricted to the research setting. Computed tomography (CT) is reserved for the evaluation of advanced disease. The use of combined positron emission tomography/CT is limited in the assessment of primary disease but is gaining acceptance in prostate cancer treatment follow-up. Evidence-based guidelines for the use of imaging in assessing the risk of distant spread of prostate cancer are available. Radionuclide bone scanning and CT supplement clinical and biochemical evaluation (prostate-specific antigen [PSA], prostatic acid phosphate) for suspected metastasis to bones and lymph nodes. Guidelines for the use of bone scanning (in patients with PSA level > 10 ng/mL) and CT (in patients with PSA level > 20 ng/mL) have been published and are in clinical use. Nevertheless, changes in practice patterns have been slow. This review presents a multidisciplinary perspective on the optimal role of modern imaging in prostate cancer detection, staging, treatment planning, and follow-up.

[MRI and staging evaluation of prostate cancer]

MRI can assess local and locoregional spread of a newly diagnosed prostate cancer by detecting extracapsular extension (ECE), seminal vesicle invasion (SVI) and lymph node invasion. Endorectal MRI remains the only accurate means to assess local extension. Pelvic MRI with surface coils and the use of superparamagnetic particules provide the sensitivity and the specificity which have never been obtained by the sole measurement of node size of the lymphatic chains draining the prostate gland. With the endorectal coil, only direct signs of extracapsular extension have been maintained and indirect signs have been discarded, giving their too low specificity. Early SVI can only be consistently detected if result of TRUS guided biopsies show involvement of the prostate base. With the pelvic phased array coil, superparamagnetic particules show that metastatic lymph nodes have a specific MR signal which can be detected in normal size nodes. Indications of imaging relies on results of parametrers available before MR imaging. More important than PSA level and Gleason score on biopsies is the so called quantitative histology, represented by the number of sextants involved by tumor and the amount of cancer (measured in mm of tumor) present on biopsies which determine a risk of extraprostatic spread. Of the risk of extraprostatic spread depends indication of MR, which is most probably unnecessary in patients at low risk (<20%) of extraprostatic extension.

Assessing the Prognostic Significance of Transrectal Ultrasound Extracapsular Extension in Prostate Cancer

AIMS

To determine the prognostic value of transrectal ultrasound (TRUS)-detected extraprostatic disease for prostate cancer in patients receiving radical external-beam radiation therapy (EBRT).

MATERIALS AND METHODS

A chart review of 181 patients treated with radical EBRT for prostate cancer was conducted. All patients underwent TRUS assessment by one radiologist. The median radiation dose delivered to the prostate was 66 Gy (range 53-70 Gy) in 33 fractions (range 20-39 fractions). Median follow-up time for all patients was 6.5 years. Sixty-four (35%) out of 181 patients were found to have extracapsular disease on TRUS. Clinical relapse was defined as the first occurrence of either salvage hormonal therapy administration by the treating oncologist or clinical, radiological, and/or pathologic evidence of recurrent or progressive disease. In terms of biochemical failure, two prognostic variable analyses were carried out using both the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus guidelines and the Houston definition of biochemical failure. The primary end point for the prognostic variable analyses was time to first clinical or biochemical failure (CBF).

RESULTS

For time to CBF using the ASTRO consensus guidelines for biochemical failure, univariable analysis revealed that the prostate-specific antigen (PSA) (P = 0.018), clinical T stage (P = 0.002), Gleason score (P = 0.021), adjuvant hormonal therapy (P = 0.032) and TRUS T staging (P = 0.0001) were statistically significant prognostic factors. On multivariable analysis, clinical T stage (P = 0.051) was of borderline statistical significance, whereas PSA (P = 0.036), TRUS T stage (P = 0.0002) and adjuvant hormonal therapy (P = 0.015) were found to be independent prognostic factors. For time to CBF using the Houston definition of biochemical failure, univariable analysis revealed that PSA (P = 0.001), Gleason score (P = 0.026) and prostate volume (P = 0.013) were statistically significant prognostic factors. On multivariable analysis, PSA (P = 0.002), Gleason score (P = 0.012), and adjuvant hormonal therapy (P = 0.041) were found to be independent prognostic factors. TRUS T staging was not found to be independently significant.

CONCLUSIONS

A clear role for TRUS staging as an independent prognostic factor, in the setting of other more established variables, such as Gleason grade, PSA, and digital rectal examination (DRE) T stage, was not confirmed in this study, population.

Validation of a Nomogram for Prediction of Side Specific Extracapsular Extension at Radical Prostatectomy

PURPOSE

We have previously have reported a tree structured regression model for predicting SS-ECE. Others recently reported a logistic regression based SS-ECE nomogram. We developed a nomogram and compared the performance and discriminant properties of the tree regression and the nomogram in a contemporary cohort of European patients treated with radical retropubic prostatectomy.

MATERIALS AND METHODS

The cohort consisted of 1,118 patients with pretreatment prostate specific antigen 0.1 to 73.2 ng/ml (median 6.6). Each of the 2,236 prostate lobes was considered separately. Clinical stage, pretreatment PSA, biopsy Gleason sum, percent positive cores and percent cancer in the biopsy specimen were used as predictors in a logistic regression model predicting SS-ECE. Regression coefficients were then used to generate an SS-ECE nomogram. Performance characteristics and discriminant properties of the previously published tree regression were also tested in the same cohort. For internal validation and to decrease overfit bias 200 bootstrap re-samples were applied to accuracy estimates for each method.

RESULTS

ECE was present in 303 of 1,118 radical retropubic prostatectomy specimens (27%) and in 385 lobes (17%). In logistic regression models all variables were statistically significant multivariate predictors of SS-ECE except the percent of positive biopsy cores (p = 0.7). Bootstrap corrected predictive accuracy of the SS-ECE nomogram was 0.840 vs 0.700 for the tree regression model.

CONCLUSIONS

Logistic regression based nomogram predictions of SS-ECE are highly accurate and represent a valuable aid for assessing the risk of ECE prior to surgery.

Development and internal validation of a nomogram predicting the probability of prostate cancer Gleason sum upgrading between biopsy and radical prostatectomy pathology

OBJECTIVE

Previous reports indicate that as many as 43% of men with low grade PCa at biopsy will be diagnosed with high-grade PCa at RP. We explored the rate of upgrading from biopsy to RP specimen in our contemporary cohort, and developed a model capable of predicting the probability of biopsy Gleason sum upgrading.

MATERIALS AND METHODS

The study cohort consisted of 2982 men treated with RP, with available clinical stage, serum prostate specific antigen and biopsy Gleason scores. These clinical data were used as predictors in multivariate logistic regression models (LRM) addressing the rate of Gleason sum upgrading between biopsy and RP pathology. LRM regression coefficients were used to develop a nomogram predicting the probability of Gleason sum upgrading and was subjected to 200 bootstrap resamples for internal validation and to reduce overfit bias.

RESULTS

Overall, 875 patients were upgraded (29.3%). In multivariate LRMs, all predictors were highly significant (all p values <0.0001). Bootstrap-corrected predictive accuracy of the nomogram predicting the probability of Gleason sum upgrading between biopsy and RP was 0.804.

CONCLUSION

We developed a highly accurate clinical aid for treatment decision-making. It may prove useful when the possibility of a more aggressive Gleason variant may change the treatment options.

Genitourinary malignancies in solid organ transplant recipients

Malignancy is a recognized complication of transplantation. Genitourinary cancers are the second most common tumors in transplant recipients with prostate cancer and renal cell carcinoma the most common. Unlike the more common skin malignancies, genitourinary tumors have a significant impact on both graft and patient survival. Surgical and radiation treatments need to consider the location of heterotopic transplants and administration of chemotherapy may need alteration in light of immunosuppression being used. The major genitourinary malignancies and their management will be reviewed in this article with emphasis on the concerns that arise in a transplant recipient.

Significance of the Percentage of Prostate Needle Biopsy Cores with Cancer as a Predictor of Disease Extension in Radical Prostatectomy Specimens in Japanese Men

OBJECTIVES

To evaluate the significance of the percent of positive biopsy cores (PPBC) with cancer, which has been shown to be one of the most useful predictors of prostate cancer extension in patients undergoing radical prostatectomy.

MATERIALS AND METHODS

This study included 120 patients who underwent radical prostatectomy for prostate cancer without any neoadjuvant therapies. All of these patients were diagnosed by random prostate biopsy targeting 8 cores; that is, standard sextant cores and 2 additional cores from the bilateral anterior lateral horns. We evaluated the appropriate cut-off points of PPBC for predicting disease extension according to the number of biopsy cores. Based on these criteria, multivariate analysis was then performed to determine whether PPBC could be an independent factor differentiating organ-confined disease from extraprostatic disease.

RESULTS

The most suitable PPBC cut-off value using findings targeting 8 cores for predicting disease extension was 37.5%. If PPBC was calculated based on the outcome of standard sextant cores alone, it is most appropriate to use 33.3% as the cut-off point. Multivariate analysis showed that PPBC calculated based on the standard sextant cores and percent of cancer in the biopsy set could be used as independent factors predicting disease extension irrespective of other biopsy-associated factors.

CONCLUSIONS

For predicting disease extension, it may be useful to calculate PPBC based on the outcomes of standard sextant biopsy cores alone even if additional cores were taken, and that PPBC calculated in such a way may be the strongest preoperative predictor of prostate cancer extension in Japanese men scheduled for radical prostatectomy.

Does body-coil magnetic-resonance imaging have a role in the preoperative staging of patients with clinically localized prostate cancer?

OBJECTIVE

To investigate the accuracy and use of body-coil magnetic resonance imaging (MRI) in the local staging of prostate cancer before radical prostatectomy (RP).

PATIENTS AND METHODS

Fifty-six patients undergoing RP were staged before surgery using body-coil MRI; none was denied surgery on the basis of their scan results. All scans were reported before RP by one of three consultant radiologists and afterward by a colleague with a special interest in prostate MRI, unaware of the patients' clinical details.

RESULTS

The overall sensitivity of MRI at detecting extracapsular extension was 50% on general reporting and 72% when reported by the specialist radiologist; the respective specificities were 84% and 86%. Of the 55 patients included in the study, 18 (33%) had extracapsular disease on histological analysis. MRI was most accurate in the 17 patients at high-risk (prostate-specific antigen, PSA, >10 ng/mL and Gleason score >or= 8) and eight at intermediate risk (PSA < 10 ng/mL and Gleason score 7). In the former group with specialist analysis, the sensitivity was 100%, although this decreased to 67% with general reporting. Both gave a specificity of 82%. Intermediate risk disease gave a sensitivity and specificity of 75%, irrespective of reporting method. The ability of MRI to detect extraprostatic tumour in the 30 low-risk patients (PSA < 10 ng/mL and Gleason score 2-6) was poor; the sensitivity was 25% with general and 50% on specialist review, although both methods gave a specificity of >90%.

CONCLUSION

Body-coil MRI is sensitive and specific for identifying extracapsular extension of prostate cancer in patients with high- or intermediate-risk disease. Patients at low risk frequently have microscopic extension which is not detected. Opinion from a radiologist with a special interest in prostate MRI can increase the reporting accuracy even when unaware of the patients' clinical details.

Prostate Cancer: Gadolinium-enhanced MR Imaging at 3 Weeks Compared with Needle Biopsy at 6 Months after Cryoablation

PURPOSE

To determine if nonenhancing tissue on gadolinium-enhanced magnetic resonance (MR) images obtained 3 weeks after cryoablation of the prostate helps reliably and accurately predict nonviable cryoablated tissue at 6-month biopsy.

MATERIALS AND METHODS

Fifty-four consecutive patients with prostate cancer who underwent cryoablation were followed up prospectively. Fifty-one underwent gadolinium-enhanced MR imaging at 3 weeks (three had gadolinium allergy); 49, biopsy at 6 months (three refused and two had other primary malignancies); and all, prostate-specific antigen (PSA) tests at 6 weeks, 3 months, and every 3 months thereafter. MR images were evaluated and scored according to the degree of signal void and were correlated with the 6-month biopsy reports and, to a lesser degree, PSA levels. The biopsy reports were examined for the presence or absence of cancerous tissue, viable tissue, and nonviable tissue. A one-way analysis of variance was used for statistical and regression analyses.

RESULTS

The correlation of MR imaging scores with PSA levels and MR imaging scores with biopsy findings resulted in P values of.337 and.780, respectively. A slight statistically significant trend existed for the relation of biopsy results with PSA levels, with a P value of.041, which was expected.

CONCLUSION

Findings of postoperative gadolinium-enhanced MR imaging are not predictive of 6-month biopsy results or follow-up PSA levels.

Value of prostate-specific antigen in the staging of Taiwanese patients with newly diagnosed prostate cancer

Records of 71 patients diagnosed with prostate cancer were reviewed retrospectively regarding clinical stage, prostate-specific antigen (PSA), Gleason score, CT scan of pelvis, bone scan, and pelvic lymph node dissection. Fourteen patients had pelvic lymphadenopathy based on the CT scan. Of these, no patient had a PSA level <4 ng/mL, 1 patient had a PSA level between 4 and 10 ng/mL, and 3 had a PSA level between 10 and 20 ng/mL. Twelve of 13 patients with positive bone scan results had a PSA level >20 ng/mL, and 1 patient had a PSA level between 10 and 20 ng/mL. PSA can be cost-effective in selecting and identifying appropriate staging for patients with newly diagnosed prostate cancer. CT scans are not indicated in men with clinical localized prostate cancer when PSA levels are < or =10 ng/mL. Bone scan is not required for staging asymptomatic men with PSA levels of < or =20 ng/mL. Pelvic lymphadenectomy for localized prostate cancer may not be necessary if PSA levels is < or =20 ng/mL and Gleason score is < or =5.

Prostate carcinoma presentation, diagnosis, and staging: an update form the National Cancer Data Base

BACKGROUND

Based on the 1998 Patient Care Evaluation (PCE) from the American College of Surgeons National Cancer Data Base (NCDB), the authors described contemporary nationwide patterns of prostate carcinoma presentation, diagnosis, and staging.

METHODS

The authors reviewed 54,212 cases from the 1998 PCE. Demographics, presenting signs and symptoms, tumor characteristics, prostate biopsy techniques, and use of staging modalities were evaluated.

RESULTS

The mean age of patients in the sample was 68 years. Among patients with available data, 87.5% had a prostate specific antigen (PSA) level of 4 ng/mL or higher, 83.1% had American Joint Committee on Cancer (AJCC) Stage I-II lesions, 80.2% had well or moderately differentiated cancers, and 68.7% of newly diagnosed patients were asymptomatic. Compared with symptomatic patients, asymptomatic patients were more likely to have localized disease (84.6% vs. 78.2%, P < 0.01) and well or moderately differentiated tumors (82.2% vs. 74.6%, P < 0.01). Transrectal ultrasound-guided prostate biopsy was the most common method of tissue confirmation (45.4%). Radionuclide bone scintigraphy was the most frequently employed staging modality (48.7%). Use of various staging evaluations was more frequent among patients at increased risk for disseminated disease (PSA > 10 ng/mL and/or high-grade tumors) versus patients at lower risk (PSA < or = 10 and low to moderate-grade tumors) for metastatic disease (P < 0.005).

CONCLUSIONS

Most newly diagnosed patients with prostate carcinoma are asymptomatic and have moderately differentiated and organ-confined disease. Compared with symptomatic patients, tumors in asymptomatic men are associated with lower pretreatment PSA levels, AJCC stage, and tumor grade. Selective use of staging evaluations, based on risk of metastatic disease, may be relatively uncommon. The NCDB remains a unique and rich source of novel patient care information and serves as a national point of reference for prostate carcinoma presentation, diagnosis, and staging.

[Prostate cancer in the Community of Madrid in the year 2000. III. Study of tumor extent]

OBJECTIVE

To identify a potential relationship between two variables, risk of metastasis and use of imaging techniques, in an extension study in prostate cancer patients diagnosed in the Autonomous Community of Madrid in 2000.

MATERIAL AND METHODS

1,127 patients with available data on the tumour extension study were analysed. Performance and non performance of bone scans and CTs were correlated to risk variables for developing metastasis as described in the literature (PSA, Gleason and stage) and to therapy administered.

RESULTS

The proportion of patients with risk variables for metastasis when bone scans were performed was between 7% to 14% greater than in patients with no variables. No differences were seen for CTs based on risk variables. With matching risk variables, more imaging techniques were used in patients receiving radiotherapy that in those managed with prostatectomy.

CONCLUSION

Based on current recommendations imaging techniques were used in excess in the extension study in patients with no risk variables for metastasis. Conduct of a further study in the Autonomous Community seems advisable to confirm the likelihood of implementing such recommendations considering our prevalence of metastatic disease.

Limited value of bone scintigraphy and computed tomography in assessing biochemical failure after radical prostatectomy

OBJECTIVES

To define the utility of bone scan and computed tomography (CT) in the evaluation of patients with biochemical recurrence after radical prostatectomy.

METHODS

A retrospective analysis of the Center for Prostate Disease Research database was undertaken to identify patients who underwent radical prostatectomy between 1989 and 1998. Patients who developed biochemical recurrence (two prostate-specific antigen [PSA] levels greater than 0.2 ng/mL) and underwent either bone scan or CT within 3 years of this recurrence were selected for analysis. The preoperative clinical parameters, pathologic findings, serum PSA levels, follow-up data, and radiographic results were reviewed.

RESULTS

One hundred thirty-two patients with biochemical recurrence and a bone scan or CT scan were identified. Of the 127 bone scans, 12 (9.4%) were positive. The patients with true-positive bone scans had an average PSA at the time of the bone scan of 61.3 +/- 71.2 ng/mL (range 1.3 to 123). Their PSA velocities, calculated from the PSA levels determined immediately before the radiographic studies, averaged 22.1 +/- 24.7 ng/mL/mo (range 0.14 to 60.0). Only 2 patients with a positive bone scan had a PSA velocity of less than 0.5 ng/mL/mo. Of the 86 CT scans, 12 (14.0%) were positive. On logistic regression analysis, PSA and PSA velocity predicted the bone scan result (P <0.001 each) and PSA velocity predicted the CT scan result (P = 0.047).

CONCLUSIONS

Patients with biochemical recurrence after radical prostatectomy have a low probability of a positive bone scan (9.4%) or a positive CT scan (14.0%) within 3 years of biochemical recurrence. Most patients with a positive bone scan have a high PSA level and a high PSA velocity (greater than 0.5 ng/mL/mo).

Quantitative biopsy pathology for the prediction of pathologically organ-confined prostate carcinoma: a multiinstitutional validation study

BACKGROUND

Quantitative biopsy pathology with prostate specific antigen significantly improves the prediction of pathologic stage in patients with clinically localized prostate carcinoma (PCa). The authors recently reported a computational model for predicting patient specific likelihood of organ confinement of PCa using biopsy pathology and clinical data. The current study validates the initial models and presents an new, improved tool for clinical decision making.

METHODS

The authors assessed 10 biopsy pathologic parameters and 2 clinical parameters using data from two institutions. Of 1287 patients, 798 men had pathologically organ confined (OC) PCa, 282 men had nonorgan-confined disease with capsular penetration (NOC-CP) only, and 207 men showed seminal vesicle or lymph node invasion (NOC-AD) after undergoing pelvic lymphadenectomy and radical prostatectomy. Patient input data were evaluated by ordinal logistic (OLOGIT) and neural network (NN) models; and the likelihood of developing OC, NOC-CP, or NOC-AD disease was calculated for the combined and separate data sets and was compared with the results from original presentation. In addition, a new two-output model was constructed (OC/NOC-CP vs. NOC-AD).

RESULTS

The three-output OLOGIT and NN models predicted OC disease with 95.0% and 98.6% accuracy, respectively, for the combined data set and with 93.0% and 98.6% accuracy, respectively, on subset analysis. The combined accuracy for predicting OC, NOC-CP, and NOC-AD disease in the entire validation set was 66.7% for OLOGIT model and 66.0% for the NN model. The two-output OLOGIT and NN models correctly predicted 94.9% and 100.0% of all OC/NOC-CP disease, respectively.

CONCLUSIONS

Both computation models predicted OC PCa with an accuracy of 93.0-98.6% when they were validated with two different data sets. The OLOGIT and NN-based, two-output model permitted an appropriate treatment decision for 85.2-90.2% of patients. These data support the use of quantitative pathology and clinical data-based decision modeling to manage patients with clinically localized PCa.

Quality of life and economic considerations in the management of prostate cancer

The purpose of this article was to provide an overview of the morbidity and mortality of prostate cancer, QOL issues and the economic impact of the disease. We searched Medline (from 1990 onwards) for all studies dealing with prostate cancer epidemiology, treatment, screening and staging, and critically reviewed the most relevant articles, focusing on pharmacoeconomic issues. Prostate cancer is the most common cancer in men. In the US, new estimated cases of prostate cancer represented 14.8% of all new cancer cases for 2000, with estimated deaths from prostate cancer comprising 5.8% of all deaths from cancer. Current options for prostate cancer management include radical prostatectomy, cryosurgery, radiotherapy, hormone therapy and watchful waiting. Many of the long-term effects of treatment, such as urinary incontinence, impotence and radiation-induced proctitis, have a large impact on patients' quality of life and, in some patients, may offset the clinical benefits. Regulatory bodies and managed care organisations are assigning increasing importance to the evaluation of QOL benefits as an independent clinical endpoint and a measure of patient satisfaction. Several screening programmes for early detection of prostate cancer, mostly based on prostate-specific antigen (PSA) measurement or digital rectal examination, have been proposed, but their routine implementation in all asymptomatic elderly men has been questioned. There is still no definite proof that patient outcomes are improved by extensive PSA screening. Furthermore, the total cost of a screening programme is difficult to define since it extends well beyond the initial test. Several instruments are used for QOL assessment in prostate cancer, some of which have been specifically developed for, or adapted to, patients with this disease, such as the Functional Assessment Cancer Therapy (FACT) tool, Prostate Cancer Treatment Outcome Questionnaire (PCTO-Q) and Prostate Cancer Specific Quality of Life Instrument (PROSQOLI). More than 50% of treatment costs for prostate cancer are accrued during the patient's last year of life, and total initial care costs decrease with increasing age. In the US, initial average inpatient costs were estimated at $US 2253, in 1995, for men aged > or =80 years, compared with $US 4540 for men aged 35-64 years. In recent years, treatments based on combined modalities (i.e. radiotherapy/prostatectomy plus hormonal therapies) have emerged. Although cost-effectiveness analyses of various treatment options have been attempted, the strength of their conclusions appears to be limited by the lack of homogeneous literature data on the effects of such interventions on survival and morbidity.

Impact of age on total and complexed prostate-specific antigen cutoffs in a contemporary referral series of men with prostate cancer

Age-specific prostate-specific antigen (PSA) cutoffs were previously suggested and were found to miss significant cancers in older men. We assessed the influence of an age-adjusted PSA cutoff to optimize the diagnostic performance (sensitivity and specificity) of complexed PSA (cPSA) and total PSA (tPSA) in the differentiation of benign disease from prostate cancer using a contemporary referral patient cohort. The cPSA and tPSA values were determined using the Bayer Immuno 1 system. The diagnostic utility of tPSA and cPSA was assessed using a diverse contemporary test population consisting of sera prospectively collected between June 1999 and October 2000 from 3597 men who recently underwent a systematic biopsy by urologists in clinical practices throughout the United States. This contemporary patient sample had biopsy diagnoses of either no evidence of malignancy (NEM; N = 2189) or prostate cancer (n = 1408). All serum samples had tPSA values between 2.0 and 20.0 ng/mL. The mean tPSAs (ng/mL) for the NEM and prostate cancer groups were 7.1 +/- 3.2 and 7.3 +/- 3.3, respectively (P = 0.026). The mean cPSAs (ng/mL) for the NEM and prostate cancer groups were 5.6 +/- 2.7 and 6.0 +/- 2.9, respectively (P <0.001). As the tPSA increased from 2.0 to 10.0 ng/mL, the cancer detection rate remained relatively constant at approximately 39% when evaluated using increments of 2.0 ng/mL for tPSA. For fixed sensitivities of 80%, 85%, 90%, and 95%, as the age range increased (45 to 59, 60 to 69, 70 to 79, >or=80), the tPSA and cPSA assay cutoffs required to sustain the specified sensitivity level markedly increased, with the exception of the 95% sensitivity level, where the cutoffs only slightly increased between the age ranges of 45 to 69 and >or=70. Overall, cPSA showed a marginal improvement in specificity versus tPSA across all age groups at all sensitivity levels. In this community referral population, the cancer detection rate remained fairly constant over the tPSA range of 2.0 to 20.0 ng/mL. This study demonstrated that to maintain a given sensitivity level for cPSA and tPSA in the age ranges studied, continuous upward adjustment of the cutoffs was required as age increased.

Comparison of Logistic Regression and Neural Net Modeling for Prediction of Prostate Cancer Pathologic Stage

Background: Prostate cancer (PCa) pathologic staging remains a challenge for the physician using individual pretreatment variables. We have previously reported that UroScoreTM, a logistic regression (LR)-derived algorithm, can correctly predict organ-confined (OC) disease state with &gt;90% accuracy. This study compares statistical and neural network (NN) approaches to predict PCa stage.

Methods: A subset (756 of 817) of radical prostatectomy patients was assessed: 434 with OC disease, 173 with capsular penetration (NOC-CP), and 149 with metastases (NOC-AD) in the training sample. Additionally, an OC + NOC-CP (n = 607) vs NOC-AD (n = 149) two-outcome model was prepared. Validation sets included 120 or 397 cases not used for modeling. Input variables included clinical and several quantitative biopsy pathology variables. The classification accuracies achieved with a NN with an error back-propagation architecture were compared with those of LR statistical modeling.

Results: We demonstrated &gt;95% detection of OC PCa in three-outcome models, using both computational approaches. For training patient samples that were equally distributed for the three-outcome models, NNs gave a significantly higher overall classification accuracy than the LR approach (40% vs 96%, respectively). In the two-outcome models using either unequal or equal case distribution, the NNs had only a marginal advantage in classification accuracy over LR.

Conclusions: The strength of a mathematics-based disease-outcome model depends on the quality of the input variables, quantity of cases, case sample input distribution, and computational methods of data processing of inputs and outputs. We identified specific advantages for NNs, especially in the prediction of multiple-outcome models, related to the ability to pre- and postprocess inputs and outputs.

Extraprostatic spread of clinically localized prostate cancer: factors predictive of pT3 tumor and of positive endorectal MR imaging examination results

PURPOSE

To identify the factor(s) most predictive of pT3 tumor and those most predictive of a positive endorectal magnetic resonance (MR) imaging result in patients with clinically localized prostate cancer.

MATERIALS AND METHODS

At multivariate analysis, five preoperative clinical parameters-prostate-specific antigen (PSA) level, digital rectal examination (DRE) result, Gleason score and number of involved sextants at transrectal US-guided biopsy, and endorectal MR imaging result-were used to predict pT3 tumor in 336 patients who underwent radical prostatectomy. On the basis of results of the first four examinations, multivariate analysis was performed also to determine predictors of a positive MR imaging study.

RESULTS

Significant predictors of pT3 tumor were positive MR imaging result (P < 2 x 10(-8)), more than one sextant involved at biopsy (P < 5 x 10(-5)), and PSA level greater than 10 ng/mL (P < 7 x 10(-3)). Significant predictors of a positive MR imaging result were three or more sextants involved at biopsy (P < 10(-5)), positive DRE result (P < 5 x 10(-3)), and PSA level greater than 10 ng/mL (P < 16 x 10(-3)). In the subgroup of 175 patients who had at least three positive biopsy specimens, the sensitivity of MR imaging was 50% for detection of occult pT3 tumor and 69% for detection of extensive pT3 tumor. The overall specificity of MR imaging was 95%.

CONCLUSION

Endorectal MR imaging seems to be indicated in carefully selected patients-specifically, those with three or more positive biopsy specimens, a palpable tumor, and/or a PSA level greater than 10 ng/mL.

[Prostate cancer: has local radiation treatment had an impact on survival?]

Local control is an important goal in the treatment of prostate cancer. Firstly, it avoids the morbidity due to locoregional evolution (urethral obstruction, vascular compression, rectal or vesical involvement). Moreover, local control of the disease may decrease the mortality due to metastases disseminated from local relapse. Local control evaluation remains difficult: neither rectal examination nor imaging or prostate biopsies have an absolute value in diagnostic of local relapse. PSA increase does not permit to differentiate local from distant relapses. Recent developments in radiotherapy techniques allow dose escalation without major toxicity. Retrospective studies and one randomized study have shown that an increase from 70 to 80 Gy or more, improve biological relapse-free survival. In one randomized study comparing 70 to 78 Gy, the biochemical disease-free survival was improved from 69 to 79% at five years. Such an improvement can only be explained by an improvement of local control. The benefit in term of overall survival is not yet demonstrated and needs a longer follow-up and other studies. Another approach to improve local control is the association of a local radiotherapy with hormonal adjuvant therapy. Four randomized studies have been published for locally advanced prostate cancer. These studies have all demonstrated an improvement of local control, and a decrease of metastatic risk. The benefit in term of overall survival, observed in one of this trial, may be explained by the improvement of either local or distant control or both. Such therapeutic progress, associated with the development of prostate cancer screening should lead to a decrease of prostate cancer mortality for the next ten years.