Mp25-09 the Utility of Psma Pet/Ct as an Additional Diagnostic Tool for Focal Therapy Patient Selection

You have accessJournal of UrologyProstate Cancer: Localized: Ablative Therapy I (MP25)1 May 2024MP25-09 THE UTILITY OF PSMA PET/CT AS AN ADDITIONAL DIAGNOSTIC TOOL FOR FOCAL THERAPY PATIENT SELECTION Kylie Y. Lim, Mohammad Asghari-Jafarabadi, Arveen Kalapara, Mark Frydenberg, and Weranja Ranasinghe Kylie Y. LimKylie Y. Lim , Mohammad Asghari-JafarabadiMohammad Asghari-Jafarabadi , Arveen KalaparaArveen Kalapara , Mark FrydenbergMark Frydenberg , and Weranja RanasingheWeranja Ranasinghe View All Author Informationhttps://doi.org/10.1097/01.JU.0001008692.26556.39.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Patient selection is critical for focal therapy (FT) success – a challenge being the undertreatment of significant prostate cancer. Prostate biopsy and MRI form the standard diagnostics for selection of patients for FT. Yet 21% of patients fail FT. We aimed to evaluate the addition of prostate-specific membrane antigen (PSMA)-positron-emission tomography (PET)/computed tomography (CT) to the current diagnostics in 1) detecting index prostate lesions and 2) excluding significant out-of-field lesions in selecting for FT. METHODS: We performed a retrospective analysis on 231 patients who underwent a radical prostatectomy (RP) and preoperative magnetic resonance imaging (MRI), PSMA PET/CT, transperineal prostate between 2015 to 2023. Standard of care (SOC) for FT was defined according to a Delphi consensus: PSA<10 ng/ml, International Society of Pathology (ISUP) grade≤3 and cancer foci <1.5ml or <3ml localised to one hemi-gland on MRI. RP specimens were defined eligible for FT with a single favourable lesion and ISUP ≤ grade 3. Sensitivity and specificity analyses were performed using RP histopathology as the gold standard. RESULTS: Sixty patients, preoperatively, met the SOC for FT criteria. The median PSA was 5.2 ng/ml (IQR 3.4-6.5), a median index tumour volume of 0.9ml (IQR 0.6-1.2) on MRI and median ISUP grade of 2 on biopsy. However, upon review of RP specimens, 40 (66%) had disease factors on RP, making these patients ineligible for FT: 80% had bilateral ISUP grade ≥ 2 disease, 12.5% underestimated large volume tumours and 7.5% extraprostatic extension. For the identification of the index lesion, SOC FT criteria had a sensitivity, specificity and positive predictive value (PPV) of 71.4%, 80.3% and 33.3% respectively. The addition of PSMA PET/CT to the SOC diagnostics improved specificity to 89.7% and PPV to 46.2% of accurately characterising the index lesion but decreased sensitivity to 64.3%. The sensitivity and specificity of excluding clinically out-of-field recurrences using SOC diagnostics were 55.8% and 91.2%. However, the addition of PSMA to the SOC diagnostics further enhanced detection of clinically significant out-of-field lesions by increasing sensitivity to 75.5%. CONCLUSIONS: The current SOC diagnostics underestimate tumour volumes and bilateral disease. The addition of PSMA PET/CT to the current SOC diagnostics improved characterisation of the index tumour and improved detection of out-of-field significant tumours. The addition of PSMA may be a beneficial diagnostic tool to optimise patient selection for FT. Source of Funding: Cabrini Foundation © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e407 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Kylie Y. Lim More articles by this author Mohammad Asghari-Jafarabadi More articles by this author Arveen Kalapara More articles by this author Mark Frydenberg More articles by this author Weranja Ranasinghe More articles by this author Expand All Advertisement PDF downloadLoading ...