PROSTAT KANSERLİ HASTALARDA PRİMER EVRELEMEDE VE NÜKS HASTALIĞIN SAPTANMASINDA 68GA-PSMA PET-BT’NİN YERİ
Akdemir, Elif Neslihan
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ABSTRACT Elif Neslihan Akdemir, The diagnostic value of PET/CT imaging with the 68Ga-labelled PSMA ligand HBED-CC in primer staging and recurrence of prostate cancer, Hacettepe University Faculty of Medicine, Department of Nuclear Medicine, Ankara 2017. Prostate-specific membrane antigen (PSMA) is a cell surface protein which shows high expression in prostate carcinoma cells. Recently introduced 68Ga labelled PSMA ligands has made tremendous advances in prostate cancer imaging. The aim of this study was to analyse clinical variables that could influence the diagnostic accuracy of 68Ga-PSMA PET/CT and investigate the clinical impact of this imaging modality on patients’ management.We performed a prospective analysis in 170 patients suffering from prostate cancer (49 staging, 121 restaging-biochemical reccurence) who underwent 68Ga-PSMA-ligand PET/CT between July 2014 to June 2016 at our department. Influence of clinical variables like prostate-specific antigen (PSA) level, PSA kinetics (dobling time (dt), velocity(v)), Gleason score (GSC), and androgen deprivation therapy (ADT) on the results of 68Ga-PSMA PET-CT were investigated. In multivariate analysis correlation between clinical features(GSC, PSA, PSA kinetics) and quantitative parameters of PET imaging (maximum lesion size (MLS), SUVmax, metabolic tumor volume (MTV), tumor index (TI)) were evaluated. Finally, we analyzed clinical impact of PSMA-imaging on the patient management. In patients with biochemical recurrence, PSA level, PSA kinetics and GSC were significantly different between PET-positive patients and PET-negative patients. PET-positive patients had higher PSA,GSC,PSAv and lower PSAdt in this patient group. There was no difference between the two groups in patients referred for staging. Patients who received ADT had higher rate of PET positivity (p:0.001). In multivariate analysis, SUVmax, MLS, MTV, TI was correlated with PSA, PSAv and GSC in patients with biochemical recurrence. In staging group, there was a significant correlation between GSC, PSA and SUVmax, MTV and TI. Disease extent was positively correlated with PSAv in patients with biochemical recurrence(p:0,01) and with GSC in newly diagnosed group (p: 0.002). ROC analysis showed that PSA 0.5 ng/mL, PSAdt 8.65 months and PSAv 2.25 ng/mL/yr were optimal cut-off values in patients with biochemical recurrence.68Ga-PSMA-ligand PET/CT detected additional vii lesions in 43 (87,7 %) of primer staging group and 72 (59,5 %) of patients with biochemical recurrencewho would have been missed using conventional morphological criteria. In 60 patient (35.2 %) therapy was changed based on 68Ga-PSMA-PET examination. In conclusion, 68Ga-PSMA-ligand PET/CT has been found to be more accurate than conventional imaging for diagnosis & follow-up of prostate cancer and significantly influenced patient management. The success of the modality was influenced by PSA kinetics, GSC and ADT. Keywords: PET/CT, prostate cancer, PSMA, biochemical recurrence, androgen deprivation therapy, PSA, PSA kinetics.