Evaluation of preoperative ProstaScint™ scans in the prediction of nodal disease

Abstract

Diagnostic methods are limited for detecting microscopic soft tissue metastases in patients with prostate cancer. Previous studies using 111 Indium Capromab Pendetide (ProstaScint TM scan) analyzed patients with extensive localized tumor (prostate specific antigen (PSA) > 20 ng/ml) not optimal for surgical therapy. We evaluated the role of the ProstaScint TM scan in a preoperative population to provide histological documentation and to assess its utility in a surgical population. A total of 22 preoperative patients, underwent a ProstaScint TM scan. The mean preoperative PSA was 16.0 ng/ml (range 3.9 -33 ng/ml). The mean Gleason score at biopsy was 6.9 (range 6 -9). Each patient underwent a radical retropubic prostatectomy and bilateral pelvic lymph node dissection, which included resection of both obturator and common iliac lymph nodes. Histologic analysis of the resected lymph nodes provided the standard of comparison with the ProstaScint TM scan. The results of the scan and pathology for all 22 patients were compared with the bilateral obturator and iliac nodes, creating 88 data points. Nine areas (10%) were positive on the scan. One of these (11%) was a true positive while the other eight (89%) were false positives. Seventy-nine areas (90%) were negative on scan results. Of these, five areas (6%) were false negatives and 74 areas (94%) were true negatives. The scan yielded a sensitivity of 17%, specificity of 90%, negative predictive value (NPV) of 94% and a positive predictive value (PPV) of 11%. The high false positive rate and low PPV of ProstaScint scans overestimates metastatic lymph nodes disease, and is not useful when used preoperatively.

Design and Synthesis of a PSMA Inhibitor–Doxorubicin Conjugate for Targeted Prostate Cancer Therapy

“…[6,7] Capromab pendetide (ProstaScint) is a commercially available monoclonal antibody in clinical use for detecting prostate cancer, but it has been cited for complexities associated with its administration and the interpretation of the images obtained. [8][9][10] PSMA is a 100 kDa, type II membrane glycoprotein highly expressed by all prostate cancers as well as by nonprostatic tumor neovasculature and the vascular endothelium of virtually all solid sarcoma and carcinoma tumors. [11][12][13][14] PSMA is highly homologous to the neuropeptidase NAALADase (GCP II) that releases the neurotransmitter glutamate from the neuronal peptide NAAG (N-acetyl-l-aspartyl-l-glutamate).…”

Induction of autoantibodies to syngeneic prostate‐specific membrane antigen by xenogeneic vaccination

“…[3][4][5][6][7] PSMA-specific monoclonal antibodies (MAb) have been used for in vivo diagnostic and therapeutic applications without adverse events. [8][9][10][11] Biochemical and objective measurable disease responses were reported in some patients treated with radionuclide conjugates of a humanized MAb, J591, that binds to the extracellular domain of PSMA. [12][13][14][15][16][17][18] The safety profile of passive immunotherapy with J591 and its derivatives, along with specific localization of radionuclide-labeled MAb to tumor sites in patients with metastatic prostate cancer or other solid tumors, supports the potential clinical benefit of antibodies and T cells specific for PSMA induced by active immunization.…”

Extended lymph node dissection for prostate cancer

“…The ProstaScint Scan (indium In 111 capromab pendetide; Cytogen Corporation, Princeton, NJ) showed a very low positive predictive value (11%) and sensitivity (17%) in predicting LN involvement [18]. Although initially promising, molecular techniques using reverse transcription polymerase chain reaction (PCR) have demonstrated varying sensitivities in detecting circulating cancer cells and positive PCR assays have been found in men with organconfined disease [19].…”