Conventional imaging modalities (CIM) have limited sensitivity and specificity for detection of metastatic prostate cancer. We examined the potential of a first-in-class radiofluorinated small-molecule inhibitor of prostate-specific membrane antigen (PSMA), (18)F-DCFBC (DCFBC), to detect metastatic hormone-naïve (HNPC) and castration-resistant prostate cancer (CRPC).
Seventeen patients were prospectively enrolled (nine HNPC and eight CRPC); 16 had CIM evidence of new or progressive metastatic prostate cancer and one had high clinical suspicion of metastatic disease. DCFBC PET/CT imaging was obtained with two successive PET scans starting at two hours post-injection. Patients were imaged with CIM at approximately the time of PET. A lesion-by-lesion analysis of PET to CIM was performed in the context of either HNPC or CRPC. The patients were followed with available clinical imaging as a reference standard to determine the true nature of identified lesions on PET and CIM.
On the lesion-by-lesion analysis, DCFBC PET was able to detect a larger number of lesions (592 positive with 63 equivocal) than CIM (520 positive with 61 equivocal) overall, in both HNPC and CRPC patients. DCFBC PET detection of lymph nodes, bone lesions, and visceral lesions was superior to CIM. When intrapatient clustering effects were taken into account, DCFBC PET was estimated to be positive in a large proportion of lesions that would be negative or equivocal on CIM (0. 45). On follow-up, the sensitivity of DCFBC PET (0. 92) was superior to CIM (0. 71). DCFBC tumor uptake was increased at the later time PET time point (~ 2. 5 hr post-injection) with background uptake showing a decreasing trend on later PET.
PET imaging with DCFBC, a small molecule PSMA-targeted radiotracer, detects more lesions than CIM and promised to diagnose and stage patients with metastatic prostate cancer more accurately than current imaging methods.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2015 Oct 22 [Epub ahead of print]
Steven P Rowe, Katarzyna J Macura, Anthony Ciarallo, Esther Mena, Amanda Blackford, Rosa Nadal, Emmanuel Antonarakis, Mario Eisenberger, Michael Carducci, Ashley Ross, Philip Kantoff, Daniel P Holt, Robert F Dannals, Ronnie C Mease, Martin G Pomper, Steve Y Cho
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