MP55-08 THE DIAGNOSTIC ACCURACY OF ⁶⁸ GA-PSMA PET/CT VERSUS MULTIPARAMETRIC MRI FOR LOCALIZING INTRA-PROSTATIC RADIORECURRENT PROSTATE CANCER

You have accessJournal of UrologyCME1 Apr 2023MP55-08 THE DIAGNOSTIC ACCURACY OF 68GA-PSMA PET/CT VERSUS MULTIPARAMETRIC MRI FOR LOCALIZING INTRA-PROSTATIC RADIORECURRENT PROSTATE CANCER Alexander Light, Stefan Lazic, Max Bayne, Martin J. Connor, Henry Tam, Hashim U. Ahmed, Tara D. Barwick, and Taimur T. Shah Alexander LightAlexander Light More articles by this author , Stefan LazicStefan Lazic More articles by this author , Max BayneMax Bayne More articles by this author , Martin J. ConnorMartin J. Connor More articles by this author , Henry TamHenry Tam More articles by this author , Hashim U. AhmedHashim U. Ahmed More articles by this author , Tara D. BarwickTara D. Barwick More articles by this author , and Taimur T. ShahTaimur T. Shah More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003308.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Local salvage therapy for men with localized radiorecurrent prostate cancer requires accurate diagnosis of intra-prostatic lesions. PSMA PET/CT is increasingly used for whole-body restaging, but its ability to localize intra-prostatic lesions is unclear. Using a histopathological reference, we compared the diagnostic accuracy of 68Ga-PSMA PET/CT to multiparametric MRI (mpMRI) for identifying intra-prostatic radiorecurrent cancer. METHODS: This is a single-center retrospective series (2017-2022) of men with a rising prostate-specific antigen post-radiotherapy, who underwent both index tests (68Ga-PSMA PET/CT and mpMRI) and a systematic and/or targeted biopsy (reference test). PET/CTs were analyzed in sextants by a single, blinded expert reader using a 5-point Likert score, with scores≥3 indicating a suspicious scan. mpMRIs were designated suspicious or non-suspicious. Sensitivity and specificity of PET/CT vs mpMRI were compared using McNemar’s test. 3 cancer definitions were studied: any cancer; Grade Group≥3 and/or maximum cancer core length (MCCL) ≥6mm (PROMIS definition 1); and Grade Group≥2 and/or MCCL ≥4mm (PROMIS definition 2). Analyses were performed at the hemi-gland level using cluster bootstrapping with 10,000 resamples. RESULTS: Of 70 eligible hemi-glands (35 men), 43 (61%) had any cancer on biopsy. PET/CT missed 6 cancers (14%) and mpMRI missed 13 (30%; p=0.07). 10 mpMRI-undetected cancers were detected by PET/CT. PET/CT had significantly higher sensitivity (0.86, 95%CI 0.76-0.95) versus mpMRI (0.70, 95%CI 0.58-0.81; p=0.049). However, specificity was not significantly different (PET/CT 0.71, mpMRI 0.59; p=0.5) (Table 1). For PROMIS definitions 1 and 2, PET/CT missed 6/37 (16%) and 6/40 (15%) cancers, respectively. mpMRI missed 10/37 (27%) definition 1 and 11/40 (28%) definition 2 cancers, of which 7 and 8 were detected by PET/CT, respectively. For both definitions, sensitivity and specificity did not significantly differ (Table 1). CONCLUSIONS: 68Ga-PSMA PET/CT had good sensitivity that improved upon mpMRI for identifying intra-prostatic radiorecurrent cancer of any grade or length. Furthermore, most mpMRI-undetected cancers were detected by PET/CT. Using both together may optimize diagnosis of intra-prostatic disease. Source of Funding: Nil © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e766 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Alexander Light More articles by this author Stefan Lazic More articles by this author Max Bayne More articles by this author Martin J. Connor More articles by this author Henry Tam More articles by this author Hashim U. Ahmed More articles by this author Tara D. Barwick More articles by this author Taimur T. Shah More articles by this author Expand All Advertisement PDF downloadLoading ...