Hot needles can confirm accurate lesion sampling intraoperatively using [¹⁸F]PSMA-1007 PET/CT-guided biopsy in patients with suspected prostate cancer.

Abstract

Prostate-specific membrane antigen (PSMA)-targeted PET is increasingly used for staging prostate cancer (PCa) with high accuracy to detect significant PCa (sigPCa). [⁶⁸ Ga]PSMA-11 PET/MRI-guided biopsy showed promising results but also persisting limitation of sampling error, due to impaired image fusion. We aimed to assess the possibility of intraoperative quantification of [¹⁸F]PSMA-1007 PET/CT uptake in core biopsies as an instant confirmation for accurate lesion sampling. In this IRB-approved, prospective, proof-of-concept study, we included five consecutive patients with suspected PCa. All underwent [¹⁸F]PSMA-1007 PET/CT scans followed by immediate PET/CT-guided and saturation template biopsy (3.1 ± 0.3 h after PET). The activity in biopsy cores was measured as counts per minute (cpm) in a gamma spectrometer. Pearson's test was used to correlate counts with histopathology (WHO/ISUP), tumor length, and membranous PSMA expression on immunohistochemistry (IHC). In 43 of 113 needles, PCa was present. The mean cpm was overall significantly higher in needles with PCa (263 ± 396 cpm) compared to needles without PCa (73 ± 44 cpm, p < 0.001). In one patient with moderate PSMA uptake (SUV_max 8.7), 13 out of 24 needles had increased counts (100-200 cpm) but only signs of inflammation and PSMA expression in benign glands on IHC. Excluding this case, ROC analysis resulted in an AUC of 0.81, with an optimal cut-off to confirm PCa at 75 cpm (sens/spec of 65.1%/87%). In all 4 patients with PCa, the first or second PSMA PET-guided needle was positive for sigPCa with high counts (156-2079 cpm). [¹⁸F]PSMA-1007 uptake in PCa can be used to confirm accurate lesion sampling of the dominant tumor intraoperatively. This technique could improve confidence in imaging-based biopsy guidance and reduce the need for saturation biopsy. NCT03187990, 15/06/2017.