Prognostic value of [18F]FDG- and PSMA-PET in patients evaluated for [177Lu]Lu-PSMA therapy of mCRPC
Tuğçe Telli, Leonor Lopes, Madeleine J. Karpinski, Kim M. Pabst, Viktor Grünwald, Kuangyu Shi, Boris Hadaschik, Claudia Kesch, Lale Umutlu, Ken Herrmann, Robert Seifert, Wolfgang P. Fendler
Abstract
Abstract Purpose To improve [ 177 Lu]Lu-Prostate-specific membrane antigen therapy (LuPSMA) selection, this study investigates the prognostic value of PSMA and 2-[ 18 F]fluoro-2-deoxy-D-glucose ([ 18 F]FDG)-PET in metastatic castration-resistant prostate cancer (mCRPC) patients considered for LuPSMA therapy. Methods We conducted a retrospective analysis in 152 mCRPC patients referred for LuPSMA therapy who underwent PSMA and [ 18 F]FDG-PET/CT. Of these, 104 patients (68.4%) underwent LuPSMA therapy, while 48 (31.6%) received other standard of care (SOC). PET/CT analyses included visual assessment and semiquantitative measurements. Clinical and laboratory parameters were recorded. Overall survival (OS) and PSA response (decline > 50%) were primary and secondary endpoints, respectively. Results Baseline [ 18 F]FDG-derived total tumor volume was the only independent predictor of overall survival both in patients subsequently treated with LuPSMA (HR 1.28 [95%CI 1.02—1.61]; p = 0.03) or in those under other SOC (HR 1.61 [95%CI 1.02—2.56]; p = 0.04), respectively. In other SOC patients, additional independent predictors of OS were total lesion PSMA uptake (PSMA-TL; HR 1.14 [95%CI 1.03–1.26]; p = 0.01), [ 18 F]FDG mean SUV (HR 20.88 [95%CI 1.2–364.74]; p = 0.04), and [ 18 F]FDG total lesion glycolysis (HR 1.61 [95%CI 1.02–2.56]; p = 0.04). In LuPSMA patients, PSMA-PET SUVmean was a significant independent predictor of PSA decline ≥ 50% (OR 2.97 [95%CI 1.27–8.16]; p = 0.02). Conclusion PSMA-PET and [ 18 F]FDG-PET provide imaging biomarkers of outcome in candidates for LuPSMA. FDG-PET total tumor volume was an independent predictor of overall survival in candidates for LuPSMA therapy, irrespective of subsequent treatment decision. PSMA-PET SUVmean was associated with biochemical response to LuPSMA. Dual tracer imaging should further be assessed in prospective trials for mCRPC treatment guidance.