Early injection of furosemide increases detection rate of local recurrence in prostate cancer patients with biochemical recurrence referred for ⁶⁸Ga-PSMA-11 PET/CT.

Abstract

Purpose: The aim of this study was to assess a) the impact of forced diuresis with early furosemide injection on the detection rate of local recurrence (LR) in prostate cancer (PC) patients with biochemical recurrence (BR) referred for ⁶⁸Ga-labelled Glu-NH-CO-NH-Lys(Ahx)-HBED-CC (⁶⁸Ga-PSMA-11) Positron Emission Tomography/Computed Tomography (PET/CT) and b) whether intravenous administration of furosemide shortly after tracer injection increases renal wash-out of ⁶⁸Ga-PSMA-11 before it binds to the PSMA-receptor with possible influence on biodistribution and intensity of tracer uptake in organs with physiologic tracer accumulation. Materials and Methods: In a retrospective analysis two different groups with 220 prostate cancer patients each, referred for ⁶⁸Ga-PSMA-11 PET/CT because of biochemical recurrence after primary therapy, were compared: patients of group one (median prostate specific antigen (PSA): 1.30 ng/ml) receiving no preparation prior to imaging, whereas patients in group two (median PSA: 0.82 ng/ml) were injected with 20 mg furosemide and 500 ml sodium chloride (NaCl 0.9%) immediately after tracer injection. Presence of local recurrence was assessed visually. In addition, intensity of tracer accumulation in organs with physiologic tracer uptake was evaluated standardized uptake value. Results: The detection rate of lesions judged positive for local recurrence was significantly higher in patients receiving furosemide compared to patients without preparation: 56 cases (25.5%) vs 38 cases (17.3%), respectively (P = 0.048). Median maximum standardized uptake values (SUV_max) of organs with physiologic uptake of ⁶⁸Ga-PSMA-11 in group one and two were: urinary bladder (63.0 vs 8.9), kidney (55.6 vs 54.5), liver (9.9 vs 9.4), spleen (11.2 vs 11.9), small bowel (16.2 vs 17.1), parotid gland (19.2 vs 19.6), lacrimal gland (8.9 vs 10.9), blood pool activity (2.2 vs 2.3), muscle (1.0 vs 1.1) and bone (1.6 vs 1.6). Apart from bladder activity, no significant reduction of tracer accumulation was found in the patient group receiving furosemide. Conclusion: Injection of 20 mg furosemide at the timepoint of radiotracer administration significantly increases the detection rate of local recurrence in prostate cancer patients with biochemical recurrence referred for ⁶⁸Ga-PSMA-11 PET/CT. As intensity of ⁶⁸Ga-PSMA-11-uptake in organs with physiologic uptake is not significantly reduced, a negative impact of early furosemide injection on targeting properties and biodistribution of ⁶⁸Ga-PSMA-11 seems unlikely.