RESUMEN
BACKGROUND: The risk of early-onset and clinically aggressive prostate cancer is elevated in carriers of certain rare pathogenic germline mutations. The utility of augmenting traditional prostate-specific antigen (PSA)-based screening measures with multiparametric magnetic resonance imaging (MRI) in this population is not yet known. OBJECTIVE: To evaluate MRI-based screening in comparison with traditional PSA-based screening among individuals at an elevated genetic risk for prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: Male germline carriers of pathogenic/likely pathogenic variants in any of 19 prostate cancer risk genes between the ages of 35 and 74 yr with no prior history of prostate cancer were recruited. Intervention Enrolled participants underwent screening with annual PSA, digital rectal examination (DRE), and triennial multiparametric MRI. Individuals with abnormal DRE, elevated age-adjusted PSA (>1.5 ng/ml for 35-49 yr, >2.0 ng/ml for 50-54 yr, and >3.0 ng/ml for 55-74 yr), or suspicious multiparametric MRI (Prostate Imaging Reporting and Data System [PI-RADS] ≥3 lesion) were offered prostate biopsy. Outcome measurements and statistical analysis Endpoints were diagnosis of any and clinically significant prostate cancer, and alternative screening strategies were compared by a decision curve analysis. RESULTS AND LIMITATIONS: To date, 101 males have completed the first round of screening. The greatest proportion of participants are carriers of BRCA2 (n = 44), BRCA1 (n = 35), and ATM (n = 7) variants. Twenty-one have undergone biopsy, resulting in the detection of nine cases of cancer (seven clinically significant). For the detection of clinically significant prostate cancer, abnormal MRI (PI-RADS ≥3) demonstrated 100% sensitivity (7/7) with a negative predictive value (NPV) of 100%, whereas PSA-based screening alone had 57% (4/7) sensitivity with an NPV of 73%. Of six screening strategies evaluated in the decision curve analysis, MRI-based screening alone achieved superior net benefit at all threshold probabilities compared with PSA screening-detecting one additional cancer case per 7.5 patients, while avoiding more unnecessary biopsies at the same threshold probability. CONCLUSIONS: Disease prevalence is high among carriers of prostate cancer-associated pathogenic germline mutations. Early results suggest that MRI-based screening enhances early detection of clinically significant disease beyond PSA screening alone. PATIENT SUMMARY: In this study, we present the interim results from the PROGRESS prostate cancer screening trial. We found that in certain germline carriers of prostate cancer risk mutations, magnetic resonance imaging-based screening enhances detection of prostate cancer while reducing biopsies triggered, in comparison with traditional prostate-specific antigen screening strategies.
RESUMEN
Quantification of platelet activation can be important for patients suffering from prothrombotic states, bleeding diatheses, cardiovascular disease, and other diseases in which platelets play a role. The analysis of platelet activation ex vivo typically requires blood processing immediately after venipuncture; this requirement can create problematic situations for both medical and research personnel. Flow cytometry is one method used to quantify platelet activation by measuring the expression of platelet surface markers with fluorescent antibodies. PAMFix is a fixative that stabilizes platelet activation markers, including P-selectin (CD62P), in whole blood. PAMFix has already been validated for use in humans and canines for stabilization of whole blood, thus allowing flow cytometry to be performed up to 28 and 22 d, respectively, after venipuncture and reducing the need for expensive equipment and highly trained personnel at the location of venipuncture. Pigtailed macaques (Macaca nemestrina) are frequently used in infectious disease research that may require containment conditions that preclude immediate processing of samples. In this study, we tested the efficacy of PAMFix on whole blood from pigtailed macaques to determine the short- and long-term effects of PAMFix on platelet P-selectin expression as analyzed by flow cytometry.
