Cancer Prevention Trial Risk Calculator Research Articles

Abdominal and back pain in a 65-year-old patient with metastatic prostate cancer

Objective Prostate cancer remains the second leading cause of cancer-related deaths, and African American men are affected with this disease disproportionately in terms of incidence and mortality. The purpose of this article is to present a case report that illustrates the importance of a careful evaluation, including a comprehensive historical review and appropriate physical and laboratory assessment, of a patient with back pain and seemingly unrelated symptoms. Clinical Features A 65-year-old African American man presented to a chiropractic clinic after experiencing lower back pain for 1 month. The digital rectal examination was unremarkable, but the serum prostate-specific antigen was markedly elevated. A suspicion of metastatic prostate cancer resulted in subsequent referral, further diagnostic evaluation, and palliation. Intervention and Outcome The patient was referred for medical evaluation and palliation of his condition. Spinal decompression surgery of the thoracic spine was initiated, resulting in weakness and paresthesia in the lower limbs bilaterally. The patient died because of the complications associated with the medical interventions and the disease about 12 months after the referral. Conclusion Chiropractic physicians should maintain a high degree of suspicion for catastrophic causes of back-related complaints, such as metastatic prostate cancer. The Prostate Cancer Prevention Trial Risk Calculator, a research validated instrument, should be used in the assessment of prostate cancer risk. Performance of the digital rectal examination and of the prostate-specific antigen determination remains integral in the clinical assessment of the health status in aging men, with or without back pain.

Evaluation of the Prostate Cancer Prevention Trial Risk calculator in a high‐risk screening population

Diagnostic (exploratory cohort). 2b. To evaluate the Prostate Cancer Prevention Trial (PCPT) risk calculator in a screening cohort of young, racially diverse, high-risk men with a low baseline prostate-specific antigen (PSA) level and enrolled in the Prostate Cancer Risk Assessment Program (PRAP). The PCPT calculator provides an assessment of prostate cancer risk based on age, PSA level, race, previous biopsy, and family history. Eligibility for PRAP includes men aged 35-69 years who are African-American, have a family history of prostate cancer, or have a known BRCA1/2 mutation. PCPT risk scores were determined for PRAP participants, and were compared to observed prostate cancer rates. In all, 624 participants were evaluated, including 382 (61.2%) African-American men and 242 (38.7%) men with a family history of prostate cancer; the median (range) age was 49.0 (34.0-69.0) years and the median PSA level 0.9 (0.1-27.2) ng/mL. The PCPT risk score correlated with prostate cancer diagnosis, as the median baseline risk score in patients diagnosed with prostate cancer was 31.3%, vs 14.2% in patients not diagnosed with prostate cancer (P < 0.001). The PCPT calculator similarly stratified the risk of diagnosis of Gleason score > or =7 disease, as the median risk score was 36.2% in patients diagnosed with Gleason > or =7 prostate cancer vs 15.2% in all other participants (P < 0.001). The PCPT risk calculator score was found to stratify prostate cancer risk in a cohort of young, primarily African-American men with a low baseline PSA level. These results support further evaluation of this predictive tool for assessing the risk of prostate cancer in high-risk men.

Performance of Prostate Cancer Prevention Trial Risk Calculator in a Contemporary Cohort Screened for Prostate Cancer and Diagnosed by Extended Prostate Biopsy

Statistical models such as the Prostate Cancer Prevention Trial risk calculator have been developed to estimate the cancer risk in an individual and help determine indications for biopsy. We assessed risk calculator performance in a large contemporary cohort of patients sampled by extended biopsy schemes. The validation cohort comprised 3,482 men who underwent a total of 4,515 prostate biopsies. Calculator performance was evaluated by ROC AUC and calibration plots. A multivariate regression model was fitted to address important predictor variables in the validation data set. Prediction error was calculated as the response variable in another multivariate regression model. Using an average of 13 cores per biopsy prostate cancer was detected in 1,862 patients. The calculator showed an AUC of 0.57 to predict all cancers and 0.60 for high grade cancer. Multivariate analysis of the predictive ability of various clinical factors revealed that race and the number of biopsy cores did not predict overall or high grade cancer at biopsy. Prior negative biopsy, patient age and free prostate specific antigen were significantly associated with prediction error for overall and high grade cancer. Race and family history had a significant association with prediction error only for high grade disease. To our knowledge our external validation of the Prostate Cancer Prevention Trial risk calculator was done in the largest cohort of men screened for prostate cancer to date. Results suggest that the current calculator remains predictive but does not maintain initial accuracy in contemporary patients sampled by more extensive biopsy schemes. Data suggest that the predictive ability of the calculator in current clinical practice may be improved by modeling contemporary data and/or incorporating additional prognostic variables.

Validation in a Multiple Urology Practice Cohort of the Prostate Cancer Prevention Trial Calculator for Predicting Prostate Cancer Detection

The Prostate Cancer Prevention Trial prostate cancer risk calculator was developed in a clinical trial cohort that does not represent men routinely referred for prostate biopsy. We assessed the generalizability of the Prostate Cancer Prevention Trial calculator in a cohort more representative of patients referred for consideration of prostate biopsy in American urology practice. Patients undergoing prostate biopsy by 12 urologists at 5 sites were enrolled in an Early Detection Research Network cohort. The Prostate Cancer Prevention Trial risk calculator was validated by examining area underneath the receiver operating characteristic curve, sensitivity, specificity and calibration comparing observed vs predicted risk of prostate cancer detection. Cancer incidence was greater (43% vs 22%, p = 0.001) in the Early Detection Research Network validation cohort (645) compared to the Prostate Cancer Prevention Trial group (5,519). Early Detection Research Network participants were younger and more racially diverse, and had more abnormal digital rectal examinations and higher prostate specific antigen than Prostate Cancer Prevention Trial participants (all p <0.001). Cancer severity was worse in the Early Detection Research Network cohort than in the Prostate Cancer Prevention Trial (Gleason 7 or higher 60% vs 21%, p <0.001). Nevertheless, the Prostate Cancer Prevention Trial risk calculator was superior to prostate specific antigen alone for predicting cancer in the Early Detection Research Network (AUC 0.691 vs 0.655, p = 0.009) and calibration confirmed that the Prostate Cancer Prevention Trial risk score accurately predicted individual risks in the Early Detection Research Network cohort. Differences between the Early Detection Research Network validation cohort and the Prostate Cancer Prevention Trial cohort underscore the importance of validating calculator performance in the multicenter urology practice setting. Our findings extend the applicability of the Prostate Cancer Prevention Trial calculator for measuring the risk of prostate cancer detection on biopsy to the routine American urology practice setting.

Multicenter Evaluation of an Investigational Prostate Cancer Methylation Assay

Prostate specific antigen tests have low specificity, which frequently results in unnecessary biopsy and typically limits screening to patients with prostate specific antigen greater than 4.0 ng/ml. We evaluated an investigational prostate cancer methylation specific polymerase chain reaction assay that detects aberrant methylation in 3 markers (GSTP1, RARbeta2 and APC) that indicate the presence of prostate cancer. The assay was evaluated in 337 post-digital rectal examination urine samples (178 cancer and 159 noncancer) collected prospectively at a total of 9 clinical sites. Samples were processed wholly or after division into equal portions. Subject prostate specific antigen was 2.0 to 10.0 ng/ml. All subjects underwent transrectal ultrasound guided needle biopsy with 6 or greater cores sampled. Detection of 1 or greater markers indicated positivity. Methylation specific polymerase chain reaction assay performance was better in whole than in divided urine cohorts (p = 0.035). Assay AUC was 0.72 in the whole urine cohort and 0.67 in the combined population. These values were higher than those of prostate specific antigen alone using 4.0 ng/ml as the cutoff (p = 0.00 and 0.01, respectively). Moreover, the assay together with the Prostate Cancer Prevention Trial risk calculator or a standard nomogram significantly improved AUC in the whole urine cohort and the combined population vs predictive algorithms alone (p <0.05). Assay positive predictive value was 54% in whole urine cohort with prostate specific antigen 2.0 to 4.0 ng/ml and negative predictive value was 87% with prostate specific antigen 4.1 to 10.0 ng/ml. Assay positive predictive value was higher in subjects with all 3 methylation markers positive. These data demonstrate that this investigational assay used in conjunction with current screening algorithms may potentially add value to the biopsy decision making process.

Critical Appraisal of Prostate-specific Antigen in Prostate Cancer Screening: 20 Years Later

Prostate-specific antigen (PSA) is secreted by all types of prostate epithelial cells and has been used for 2 decades as a biologic marker for prostate cancer (PCa). Since the implementation of PSA screening in the United States, the detection of PCa has increased, accompanied by a decrease in the incidence of high-grade cancer and PCa-specific mortality rates. It has been suggested that these decreases have resulted from the enhanced detection of PCa while still curable. These data have been the impetus for early detection programs, which have recommended the initiation of screening as early as 40 years of age. Despite widespread use, PSA screening remains controversial, principally because of the lack of evidence from randomized controlled trials demonstrating a mortality benefit that could outweigh the concerns of the costs of overdiagnosis and overtreatment. Two ongoing, randomized controlled trials are examining whether screening reduces the risk of PCa-related mortality, and the results of these studies are expected soon. Although it has its limitations, PSA still remains the best-studied marker for the detection of PCa.

Predicting Prostate Cancer Risk Through Incorporation of Prostate Cancer Gene 3

The online Prostate Cancer Prevention Trial risk calculator combines prostate specific antigen, digital rectal examination, family and biopsy history, age and race to determine the risk of prostate cancer. In this report we incorporate the biomarker prostate cancer gene 3 into the Prostate Cancer Prevention Trial risk calculator. Methodology was developed to incorporate new markers for prostate cancer into the Prostate Cancer Prevention Trial risk calculator based on likelihood ratios calculated from separate case control or cohort studies. The methodology was applied to incorporate the marker prostate cancer gene 3 into the risk calculator based on a cohort of 521 men who underwent prostate biopsy with measurements of urinary prostate cancer gene 3, serum prostate specific antigen, digital rectal examination and biopsy history. External validation of the updated risk calculator was performed on a cohort of 443 European patients, and compared to Prostate Cancer Prevention Trial risks, prostate specific antigen and prostate cancer gene 3 by area underneath the receiver operating characteristic curve, sensitivity and specificity. The AUC of posterior risks (AUC 0.696, 95% CI 0.641-0.750) was higher than that of prostate specific antigen (AUC 0.607, 95% CI 0.546-0.668, p = 0.001) and Prostate Cancer Prevention Trial risks (AUC 0.653, 95% CI 0.593-0.714, p <0.05). Although it was higher it was not statistically significantly different from that of prostate cancer gene 3 (AUC 0.665, 95% CI 0.610-0.721, p >0.05). Sensitivities of posterior risks were higher than those of prostate cancer gene 3, prostate specific antigen and Prostate Cancer Prevention Trial risks. New markers for prostate cancer can be incorporated into the Prostate Cancer Prevention Trial risk calculator by a novel approach. Incorporation of prostate cancer gene 3 improved the diagnostic accuracy of the Prostate Cancer Prevention Trial risk calculator.

Current Age and Race Adjusted Prostate Specific Antigen Threshold Values Delay Diagnosis of High Grade Prostate Cancer

Age specific prostate specific antigen ranges have been advocated to increase the predictive value of prostate specific antigen based on increases that occur with aging. We suggest that prostate specific antigen is not a dichotomous biomarker and age specific reference ranges delays the diagnosis of high grade prostate cancer in older and black American men. Using the Prostate Cancer Prevention Trial risk calculator we evaluated the impact of age on the risk of high grade prostate cancer in white and black men. We created a hypothetical population of men by standardizing risk variables, including negative family history, normal digital rectal examination and no history of negative biopsy. Results were compared in the 2 populations using 5-year age increments from ages 55 to 75 years and increasing prostate specific antigen. Increasing age was associated with a higher risk of high grade prostate cancer in white and black men. The risk of high grade prostate cancer in a black man was twice that in a white man with the same prostate specific antigen at all prostate specific antigen values. Age specific and race specific prostate specific antigen ranges are flawed. Many patients who would not be considered for biopsy based on these prostate specific antigen ranges are at significant risk for high grade prostate cancer. The risk of high grade prostate cancer in black men is twice that in white men. Risk assessment in black men and older men is necessary to diagnose high grade prostate cancer when treatment can be effective.

1873: External Validation of the Prostate Cancer Prevention Trial Risk Calculator in a Screened Population

1873: External Validation of the Prostate Cancer Prevention Trial Risk Calculator in a Screened Population

External validation of the Prostate Cancer Prevention Trial risk calculator in a screened population

Objectives To evaluate the recently developed Prostate Cancer Prevention Trial (PCPT) prostate cancer risk calculator in the San Antonio Center of Biomarkers of Risk for Prostate Cancer (SABOR) cohort of the Early Detection Research Network, a younger and more ethnically diverse population than that in the PCPT. Methods From 3488 SABOR participants, we identified 446 who had undergone prostate biopsy and had undergone prostate-specific antigen measurement and digital rectal examination before biopsy. Most biopsies were performed for abnormal digital rectal examination findings, a prostate-specific antigen level of more than 2.5 ng/mL, or elevated risk because of a first-degree relative with prostate cancer. We evaluated the operating characteristics of the PCPT calculator for detecting prostate cancer in this cohort of SABOR participants. Of the 446 men in this cohort, 24% were younger than 55 years of age. Results Of the 446 men who had undergone biopsy, 148 (33.2%) had prostate cancer. The observed SABOR prostate cancer rates increased with increasing PCPT risk: 15.7%, 39.0%, 48.8%, and 100.0% for a PCPT risk calculator value of less than 25%, 25% to 50%, 50% to 75%, and greater than 75%, respectively. The PCPT risk calculator had an area under the receiver operating characteristic curve of 65.5% (95% confidence interval 60.2% to 70.8%, P <0.0001), was greater in African-American men (area under curve of 80.0%, 95% confidence interval 67.8% to 92.2%) than in other races ( P = 0.02), and was not different in Hispanic men ( P >0.05). Conclusions The results of our study have shown that the PCPT risk calculator, available from the Internet and incorporating the current best panel of risk factors, is valid in other, more diverse, populations.