99mTc‐MIP‐1404‐SPECT/CT for the detection of PSMA‐positive lesions in 225 patients with biochemical recurrence of prostate cancer

Background 99mTc‐MIP‐1404 (Progenics Pharmaceuticals, Inc., New York, NY) is a novel, SPECT‐compatible 99mTc‐labeled PSMA inhibitor for the detection of prostate cancer. We present results of its clinical use in a cohort of 225 men with histologically confirmed prostate cancer referred for workup of biochemical relapse. Methods From April 2013 to April 2017, 99mTc‐MIP1404‐scintigraphy was performed in 225 patients for workup of PSA biochemical relapse of prostate cancer. Whole‐body planar and SPECT/CT images of the lower abdomen and thorax were obtained 3‐4 h p.i. of 710 ± 64 MBq 99mTc‐MIP‐1404. Images were visually analyzed for presence and location of abnormal uptake. In addition, quantitative analysis of the SPECT/CT data was carried out on a subset of 125 patients. Follow‐up reports of subsequent therapeutic interventions were available for 59% (139) of all patients. Results Tracer‐positive lesions were detected in 77% (174/225) of all patients. Detections occurred at the area of local recurrence in the prostate in 25% of patients (or a total of 56), with metastases in lymph nodes in 47% (105), bone in 27% (60), lung in 5% (12), and other locations in 2% (4) of patients. Detection rates were 90% at PSA levels ≥2 ng/mL and 54% below that threshold. Lesional SUVmax values were, on average, 32.2 ± 29.6 (0.8–142.2), and tumor‐to‐normal ratios 146.6 ± 160.5 (1.9–1482.4). The PSA level correlated significantly with total uptake of MIP‐1404 in tumors (P