BACKGROUND: Literature lacks clear evidence regarding the optimal treatment for non-muscle-invasive micropapillary bladder cancer (MPBC) due to its rarity and the presence of only small sample size and single-centre studies. OBJECTIVE: To assess cancer-specific mortality (CSM) and overall mortality (OM) between immediate radical cystectomy (RC) and conservative management among T1 high-grade (HG) MPBC. DESIGN, SETTING, AND PARTICIPANTS: We retrospectively analysed a multicentre dataset including 119 T1 HG MPBC patients treated between 2005 and 2019 at 15 tertiary referral centres. The median follow-up time was 35 mo (interquartile range: 19-64). INTERVENTION: Patients underwent immediate RC versus conservative management with bacillus Calmette-Guérin. OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS: Cumulative incidence functions and Kaplan-Meier methods were applied to estimate survival outcomes. Multivariable Cox analyses were performed to assess independent predictors of disease recurrence and disease progression after conservative management; covariates consisted of pure MPBC, concomitant lymphovascular invasion (LVI), and carcinoma in situ at initial diagnosis. RESULTS AND LIMITATIONS: Immediate RC and conservative management were performed in 27% and 73% of patients, respectively. CSM and OM did not differ significantly among patient treated with immediate RC versus conservative management (Pepe-Mori test p = 0.5 and log-rank test p = 0.9, respectively). Overall, 66.7% and 34.5% of patients experienced disease recurrence and disease progression after conservative management, respectively. At multivariable Cox analyses, concomitant LVI was an independent predictor of disease recurrence (p = 0.01) and progression (p = 0.03), while pure MPBC was independently associated with disease progression (p = 0.03). The absence of a centralised re-review and the retrospective design represent the main limitations of our study. CONCLUSIONS: Conservative management could achieve satisfactory results among T1 HG MPBC patients with neither pure MPBC nor LVI at initial diagnosis. PATIENT SUMMARY: Bacillus Calmette-Guérin seems to be an effective therapy for T1 micropapillary bladder cancer patients with neither pure micropapillary disease nor lymphovascular invasion at initial diagnosis.

APHP Department of Urology Hôpital Saint Louis Université de Paris Paris France

Department of Experimental and Clinical Medicine Unit of Oncologic Minimally Invasive Urology and Andrology Careggi University Hospital University of Florence Florence Italy

Department of Medical Oncology Urological Research Institute IRCCS Ospedale San Raffaele Milan Italy; University Vita Salute San Raffaele Milan Italy

Department of Surgery Prince of Wales Hospital The Chinese University of Hong Kong Hong Kong China

Department of Urology and Oncological Urology Wrocław Medical University Wrocław Poland

Department of Urology Charité Universitätsmedizin Berlin Berlin Germany

Department of Urology Comprehensive Cancer Center Medical University of Vienna Vienna General Hospital Vienna Austria

Department of Urology Comprehensive Cancer Center Medical University of Vienna Vienna General Hospital Vienna Austria; Institute for Urology and Reproductive Health Sechenov University Moscow Russia

Department of Urology Comprehensive Cancer Center Medical University of Vienna Vienna General Hospital Vienna Austria; Institute for Urology and Reproductive Health Sechenov University Moscow Russia; Department of Urology Weill Cornell Medical College New York NY USA; Department of Urology University of Texas Southwestern Medical Center Dallas TX USA; Department of Urology 2nd Faculty of Medicine Charles University Prague Czech Republic

Department of Urology Fundación Instituto Valenciano de Oncologia Valencia Spain

Department of Urology IRCCS Humanitas Research Hospital Rozzano Milan Italy

Department of Urology Ludwig Maximilians University Munich Germany

Department of Urology Luzerner Kantonsspital Lucerne Switzerland

Department of Urology Luzerner Kantonsspital Lucerne Switzerland; Clinica Luganese Moncucco Lugano Switzerland; Clinica S Anna Swiss Medical Group Sorengo Switzerland; Clinica Santa Chiara Locarno Switzerland

Department of Urology Luzerner Kantonsspital Lucerne Switzerland; Division of Experimental Oncology Unit of Urology Urological Research Institute IRCCS Ospedale San Raffaele Milan Italy

Department of Urology Spedali Civili di Brescia Brescia Italy

Department of Urology Spedali Civili di Brescia Brescia Italy; Department of Urology Luzerner Kantonsspital Lucerne Switzerland

Department of Urology The Netherlands Cancer Institute Amsterdam The Netherlands

Department of Urology Tokyo Medical and Dental University Graduate School Yushima Bunkyo ku Tokyo Japan

Department of Urology University of Verona Azienda Ospedaliera Universitaria Integrata Verona Verona Italy

Division of Experimental Oncology Unit of Urology Urological Research Institute IRCCS Ospedale San Raffaele Milan Italy

Division of Experimental Oncology Unit of Urology Urological Research Institute IRCCS Ospedale San Raffaele Milan Italy; University Vita Salute San Raffaele Milan Italy

Division of Urology Department of Surgical Sciences AOU Città della Salute e della Scienza di Torino Torino School of Medicine Torino Italy

GRC 5 Predictive Onco Uro AP HP Urology Pitie Salpetriere Hospital Sorbonne University Paris France

References provided by Crossref.org