Utilization of 111In-Capromab pendetide SPECT-CT for detecting seminal vesicle invasion with recurrent prostate cancer after primary in situ therapy

The aim of this study was to evaluate the diagnostic value of a hybrid 111In-capromab pendetide fused computed tomography (CT) scan in detecting seminal vesicle invasion (SVI) in the setting of recurrent prostate cancer following primary in situ therapy. The study population comprised 59 patients, who biochemically failed primary in situ treatment based on American Society for Therapeutic Radiology and Oncology criteria. The patients underwent an 111In-capromab pendetide/CT scan at the time of biochemical failure with a prostate (12-core) and seminal vesicle (SV) (8-core) biopsy. The diagnostic properties of the scan and magnetic resonance imaging (MRI) in detecting SVI compared to an SV biopsy were calculated. In total, eight (14%) patients had a positive SV biopsy after primary in situ prostate cancer treatment. Nine (15%) patients had positive uptake of the scan in the SV. When comparing the SV scan results to the SV biopsy, the sensitivity, specificity, positive predictive value, and negative predictive value were 37.5%, 88.2%, 33.3%, and 90.0% (95% confidence interval: 0.44-0.81), respectively. In contrast, the ability of MRI to detect SVI was 50.0%, 81.3%, 40.0%, and 86.7% (95% confidence interval: 0.46-0.85), respectively. Although the sensitivity and positive predictive value of the 111In-capromab pendetide/CT scan are low, its specificity and negative predictive value are high. Based on these findings, the ability of the 111In-capromab pendetide/CT scan to detect SVI seems to be comparable with MRI.