PD09-02 THE IMPACT OF VARIANT HISTOLOGY ON CLINICAL OUTCOMES AFTER RADIATION-BASED THERAPY FOR MUSCLE-INVASIVE BLADDER CANCER

Abstract

You have accessJournal of UrologyCME1 Apr 2023PD09-02 THE IMPACT OF VARIANT HISTOLOGY ON CLINICAL OUTCOMES AFTER RADIATION-BASED THERAPY FOR MUSCLE-INVASIVE BLADDER CANCER Daniel Halstuch, Ronald Kool, Gautier Marcq, Rodney H Breau, Peter C Black, Bobby Shayegan, Michael Kim, Ionut Busca, Hamidreza Abdi, Mark T. Dawidek, Michael Uy, Gagan Fervaha, Fabio L. Cury, Nimira S. Alimohamed, Claudio Jeldres, Ricardo Rendon, D. Robert Siemens, Girish S. Kulkarni, Wassim Kassouf, and Jonathan I. Izawa Daniel HalstuchDaniel Halstuch More articles by this author , Ronald KoolRonald Kool More articles by this author , Gautier MarcqGautier Marcq More articles by this author , Rodney H BreauRodney H Breau More articles by this author , Peter C BlackPeter C Black More articles by this author , Bobby ShayeganBobby Shayegan More articles by this author , Michael KimMichael Kim More articles by this author , Ionut BuscaIonut Busca More articles by this author , Hamidreza AbdiHamidreza Abdi More articles by this author , Mark T. DawidekMark T. Dawidek More articles by this author , Michael UyMichael Uy More articles by this author , Gagan FervahaGagan Fervaha More articles by this author , Fabio L. CuryFabio L. Cury More articles by this author , Nimira S. AlimohamedNimira S. Alimohamed More articles by this author , Claudio JeldresClaudio Jeldres More articles by this author , Ricardo RendonRicardo Rendon More articles by this author , D. Robert SiemensD. Robert Siemens More articles by this author , Girish S. KulkarniGirish S. Kulkarni More articles by this author , Wassim KassoufWassim Kassouf More articles by this author , and Jonathan I. IzawaJonathan I. Izawa More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003240.02AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Radiation-based therapy (RT) is an acceptable bladder-preserving treatment for selected patients with muscle-invasive bladder cancer (MIBC). Real-world outcomes of RT-based therapy for histologic variants are lacking. Our objective was to compare oncological outcomes between pure urothelial carcinoma (PUC) and variant urothelial carcinoma (UC-HV) patients with MIBC treated with RT-based therapy. METHODS: A collaborative Canadian multicenter retrospective study of 864 patients with MIBC who underwent curative-intent bladder-sparing RT for T2-4a N0-3 M0 MIBC between 2001-2018. Tumours were classified based on the presence of non-urothelial components as either PUC or UC-HV. A complete response (CR) was defined by a negative tumour bed biopsy and/or the combination of a negative urine cytology, negative cystoscopy and normal imaging post-RT. Loco-regional disease-free survival (LR-DFS), disease-free survival (DFS), metastasis-free survival (MFS), cancer-specific survival (CSS) and overall survival (OS) were calculated using Kaplan-Meier method. Cox regression models were used to estimate the effect of UC-VH on oncologic outcomes for patients with MIBC treated with RT-based therapy. RESULTS: Of 864 patients treated with RT-based therapy, 123 (14.2%) had UC-HV. Seventy-five (61%) had UC-HV with squamous and/or glandular differentiation and 48 (39%) had other variants. A CR after RT-based therapy was confirmed in 69.1% of patients with PUC and 63.4% with UC-HV (p=0.266). The 5-yr CSS was 62.0% in PUC vs. 66.8% in UC-HV. The 5-yr OS was 47.7% in PUC and 53.3% in UC-HV. Rates of LR-DFS, DFS and MFS at 5 years were not statistically different between the groups. Salvage cystectomy (sRC) rates were similar (p=0.781). In the univariate Cox regression analyses, UC-HV status was not associated with inferior LR-DFS, DFS, MFS, CSS, and OS. CONCLUSIONS: Variant histology of urothelial carcinoma responded to RT-based therapy with no significant difference in CR, LR-DFS, DFS, MFS, CSS, OS, or rates of salvage cystectomy compared to PUC. The presence of variant histology in MIBC does not confer resistance to RT-based therapy and these patients should not be excluded from bladder preservation treatment. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e239 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Daniel Halstuch More articles by this author Ronald Kool More articles by this author Gautier Marcq More articles by this author Rodney H Breau More articles by this author Peter C Black More articles by this author Bobby Shayegan More articles by this author Michael Kim More articles by this author Ionut Busca More articles by this author Hamidreza Abdi More articles by this author Mark T. Dawidek More articles by this author Michael Uy More articles by this author Gagan Fervaha More articles by this author Fabio L. Cury More articles by this author Nimira S. Alimohamed More articles by this author Claudio Jeldres More articles by this author Ricardo Rendon More articles by this author D. Robert Siemens More articles by this author Girish S. Kulkarni More articles by this author Wassim Kassouf More articles by this author Jonathan I. Izawa More articles by this author Expand All Advertisement PDF downloadLoading ...