Comparison of Multiple Segmentation Methods for Volumetric Delineation of Primary Prostate Cancer with Prostate-Specific Membrane Antigen-Targeted 18F-DCFPyL PET/CT.

This study aimed to assess the accuracy of intraprostatic tumor volume measurements on prostate-specific membrane antigen-targeted 18F-DCFPyL PET/CT made with various segmentation methods. An accurate understanding of tumor volumes versus segmentation techniques is critical for therapy planning, such as radiation dose volume determination and response assessment. Methods: Twenty-five men with clinically localized, high-risk prostate cancer were imaged with 18F-DCFPyL PET/CT before radical prostatectomy. The tumor volumes and tumor-to-prostate ratios (TPRs) of dominant intraprostatic foci of uptake were determined using semiautomatic segmentation (applying SUVmax percentage [SUV%] thresholds of SUV30%-SUV70%), adaptive segmentation (using adaptive segmentation percentage [A%] thresholds of A30%-A70%), and manual contouring. The histopathologic tumor volume (TV-Histo) served as the reference standard. The significance of differences between TV-Histo and PET-based tumor volume were assessed using the paired-sample Wilcoxon signed-rank test. The Spearman correlation coefficient was used to establish the strength of the association between TV-Histo and PET-derived tumor volume. Results: Median TV-Histo was 2.03 cm3 (interquartile ratio [IQR], 1.16-3.36 cm3), and median TPR was 10.16%. The adaptive method with an A40% threshold most closely determined the tumor volume, with a median difference of +0.19 (IQR, -0.71 to +2.01) and a median relative difference of +7.6%. The paired-sample Wilcoxon test showed no significant difference in PET-derived tumor volume and TV-Histo using A40%, A50%, SUV40%, and SUV50% threshold segmentation algorithms (P > 0.05). For both threshold-based segmentation methods, use of higher thresholds (e.g., SUV60% or SUV70% and A50%-A70%) resulted in underestimation of tumor volumes, and use of lower thresholds (e.g., SUV30% or SUV40% and A30%) resulted in overestimation of tumor volumes relative to TV-Histo and TPR. Manual segmentation overestimated the tumor volume, with a median difference of +2.49 (IQR, 0.42-4.11) and a median relative difference of +130%. Conclusion: Segmentation of intraprostatic tumor volume and TPR with an adaptive segmentation approach most closely approximates TV-Histo. This information might be used to guide the primary treatment of men with clinically localized, high-risk prostate cancer.

Prospective Evaluation of PSMA-Targeted 18F-DCFPyL PET/CT in Men with Biochemical Failure After Radical Prostatectomy for Prostate Cancer.

Our purpose is to provide the results of a prospective study evaluating prostate-specific membrane antigen-targeted 18F-DCFPyL (2-(3-{1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid) PET/CT in patients with biochemical failure after radical prostatectomy for prostate cancer (PCa). Methods: Thirty-one patients with postprostatectomy serum prostate-specific antigen (PSA) levels of at least 0.2 ng/mL and negative conventional imaging results were enrolled in this study and imaged with 18F-DCFPyL PET/CT. A consensus central review identified foci of radiotracer uptake consistent with sites of PCa. Descriptive statistics were used. Results: Twenty-one patients (67.7%) had at least 1 finding on 18F-DCFPyL PET/CT consistent with a site of PCa. Imaging was positive in 59.1% of patients with a PSA level of less than 1.0 ng/mL and in 88.9% of patients with a PSA level of more than 1.0 ng/mL. The median SUVmax across all lesions was 11.6 (range, 1.5-57.6). Conclusion: In this prospective study using the prostate-specific membrane antigen-targeted PET agent 18F-DCFPyL, most patients with biochemical failure after radical prostatectomy had foci of suggestive uptake, even at low serum PSA levels.

Prostate Specific Membrane Antigen Targeted 18F-DCFPyL Positron Emission Tomography/Computerized Tomography for the Preoperative Staging of High Risk Prostate Cancer: Results of a Prospective, Phase II, Single Center Study.

PURPOSE: We prospectively evaluated the diagnostic performance of prostate specific membrane antigen targeted 18F-DCFPyL positron emission tomography/computerized tomography in the preoperative staging of men at high risk for harboring metastatic prostate cancer despite a negative conventional staging evaluation. MATERIALS AND METHODS: Men with clinically localized high or very high risk prostate cancer were imaged with 18F-DCFPyL positron emission tomography/computerized tomography before undergoing radical prostatectomy with standardized pelvic lymph node dissection. The scans were interpreted by 2 blinded nuclear medicine readers and assessed for interreader variability as well as diagnostic accuracy for pelvic lymph node staging. Surgical pathology served as the reference standard to which 18F-DCFPyL scan findings were compared. RESULTS: A total of 25 men contributed analyzable data to this study. Seven of these patients (28%) were found to have 1 or more positive lymph nodes on surgical pathology. Sites of radiotracer uptake were identified in the prostate of all imaged patients. The 2 readers identified the same number of prostatic lesions in 22 patients (88%), of whom all had at least 1 intraprostatic lesion in common between the 2 reads. Additionally, the readers assigned the same N stage to 46 of 50 individual lymph node packets (92%). Following reconciliation of the relatively few discordant imaging reads, 7 patients (28%) were found to have 1 or more sites of radiotracer uptake in the pelvis consistent with N1 disease, resulting in 71.4% sensitivity (95% CI 29.0-96.3) and 88.9% specificity (95% CI 65.3-98.6). Analysis at the level of individual nodal packets resulted in 66.7% sensitivity (95% CI 29.9-92.5) and 92.7% specificity (95% CI 80.1-98.5). Three men (12%) had evidence of M1a disease. CONCLUSIONS: 18F-DCFPyL positron emission tomography/computerized tomography allowed for accurate detection of prostate cancer sites in men believed to have clinically localized disease based on conventional imaging. Our results support the need for a larger study to more precisely define the diagnostic accuracy of this novel molecular imaging test.

Factors influencing resource use by African American and African Caribbean women disclosing intimate partner violence.

Many victims of intimate partner violence (IPV) do not access services. Education and severity of physical violence have previously been shown to predict resource utilization, but whether these hold true specifically among women of African descent is unknown. This article furthers our understanding of the relationship between IPV and resource use, considering sociodemographics and aspects of IPV by presenting results from a study conducted with African American and African Caribbean women in Baltimore, Maryland, and the U.S. Virgin Islands. Of the 545 women included in this analysis, 95 (18%) reported emotional abuse only, 274 (50%) reported experiencing physical abuse only, and 176 (32%) had experienced both physical and sexual abuse by an intimate partner. Resource utilization was relatively low among these women, with only 57% seeking any help. Among those who did, 13% sought medical, 18% DV, 37% community, and 41% criminal justice resources. Generalized linear model results indicated that older age and severe risk for lethality from IPV and PTSD were predictive of certain types of resource use, while education, insurance status, and depression had no influence. Perceived availability of police and shelter resources varied by site. Results suggest that systems that facilitate resource redress for all abused women are essential, particularly attending to younger clients who are less likely to seek help, while building awareness that women accessing resources may be at severe risk for lethality from the violence and may also be experiencing mental health complications. In addition, greater efforts should be made on the community level to raise awareness among women of available resources.