Survival After Partial Cystectomy for Variant Histology Bladder Cancer Compared With Urothelial Carcinoma: A Population-based Study

Survival After Partial Cystectomy for Variant Histology Bladder Cancer Compared With Urothelial Carcinoma: A Population-based Study

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Journal Pre-proof Survival after partial cystectomy for variant histology bladder cancer compared to urothelial carcinoma: a population-based study Stefano Luzzago, Carlotta Palumbo, Giuseppe Rosiello, Sophie Knipper, Angela Pecoraro, Marina Deuker, Francesco Alessandro Mistretta, Zhe Tian, Gennaro Musi, Emanuele Montanari, Shahrokh F. Shariat, Fred Saad, Alberto Briganti, Ottavio de Cobelli, Pierre I. Karakiewicz PII:

S1558-7673(19)30320-9

DOI:

https://doi.org/10.1016/j.clgc.2019.10.016

Reference:

CLGC 1378

To appear in:

Clinical Genitourinary Cancer

Received Date: 8 August 2019 Revised Date:

1 October 2019

Accepted Date: 6 October 2019

Please cite this article as: Luzzago S, Palumbo C, Rosiello G, Knipper S, Pecoraro A, Deuker M, Mistretta FA, Tian Z, Musi G, Montanari E, Shariat SF, Saad F, Briganti A, de Cobelli O, Karakiewicz PI, Survival after partial cystectomy for variant histology bladder cancer compared to urothelial carcinoma: a population-based study, Clinical Genitourinary Cancer (2019), doi: https://doi.org/10.1016/ j.clgc.2019.10.016. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Elsevier Inc. All rights reserved.

Microabstract

Within the SEER database, we evaluated cancer-specific mortality (CSM) in 248 T1-2N0M0 variant histology bladder cancer patients (nonUCUB) treated with partial cystectomy (PC). In Cox regression models, nonUCUB PC treated patients exhibited higher CSM, compared to urothelial carcinoma patients treated with PC. Conversely, nonUCUB patients treated with PC had similar CSM when compared to nonUCUB patients treated with radical cystectomy.

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Survival after partial cystectomy for variant histology bladder cancer compared

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to urothelial carcinoma: a population-based study

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Stefano Luzzagoa,b, Carlotta Palumboa,c Giuseppe Rosielloa,d, Sophie Knippera,e,

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Angela Pecoraroa,f, Marina Deukerg, Francesco Alessandro Mistrettaa,b, Zhe Tiana,

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Gennaro Musib, Emanuele Montanarih, Shahrokh F. Shariati,l,m,n,o, Fred Saada,

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Alberto Brigantib, Ottavio de Cobellib,p, Pierre I. Karakiewicza

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a

Cancer Prognostics and Health Outcomes Unit, Division of Urology, University of Montreal Health

Center, Montreal, Quebec, Canada

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b

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c

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Radiological Science and Public Health, University of Brescia, Italy

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d

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IRCCS San Raffaele Scientific Institute, Milan, Italy

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e

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Germany

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f

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g

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h

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of Milan, Milan, Italy

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i

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Austria

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l

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m

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n

Department of Urology, Second Faculty of Medicine, Charles University, Prag, Czech Republic

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o

Institute for Urology and Reproductive Health, I.M. Sechenov First Moscow State Medical

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University, Moscow, Russia

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p

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Word count (abstract): 250

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Word count (manuscript): 2378

Department of Urology, European Institute of Oncology, Milan, Italy

Urology Unit, ASST Spedali Civili of Brescia. Department of Medical and Surgical Specialties,

Department of Urology and Division of Experimental Oncology, URI, Urological Research Institute,

Martini-Klinik Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg,

Department of Urology, San Luigi Gonzaga Hospital, University of Turin, Turin, Italy Department of Urology, University Hospital Frankfurt, Frankfurt am Main, Germany. Department of Urology, IRCCS Fondazione Ca’ Granda-Ospedale Maggiore Policlinico, University

Department of Urology, Comprehensive Cancer Center, Medical University of Vienna, Vienna,

Departments of Urology, Weill Cornell Medical College, New York, New York, USA Department of Urology, University of Texas Southwestern, Dallas, Texas, USA

Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy

Corresponding author: Stefano Luzzago, MD Department of Urology, European Institute of Oncology, Milan, Italy Via Giuseppe Ripamonti, 435 20141 Milan, Italy Tel: +39 33354249298 E-mail: [email protected]

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Declarations of interest: none

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List of abbreviations

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PC: Partial cystectomy

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RC: Radical cystectomy

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UCUB: Urothelial carcinoma of the urinary bladder

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nonUCUB: Variant histology bladder cancer

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CSM: cancer-specific mortality

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SEER: Surveillance, Epidemiology and End Results

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ICD-O: International Classification of Disease for Oncology

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WHO: World Health Organization

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IPTW: Inverse Probability of Treatment Weighting

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IQR: interquartile range

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CI: confidence interval

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HR: Hazard Ratio

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2

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Abstract

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Background

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To test cancer-specific mortality (CSM) after partial cystectomy (PC) for variant histology bladder

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cancer (nonUCUB), relative to urothelial carcinoma of the urinary bladder (UCUB) and relative to

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radical cystectomy (RC).

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Materials and Methods

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Within the Surveillance, Epidemiology, and End Results registry (2001–2016), we identified

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T1-2,N0,M0 nonUCUB and UCUB patients treated with PC and corresponding groups treated with

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RC. Non-UCUB included adenocarcinoma, squamous carcinoma, neuroendocrine carcinoma, other

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histological subtypes. First, CSM after PC was compared between nonUCUB and UCUB. Second,

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CSM after PC was compared to RC in nonUCUB. Kaplan Meier plots and multivariable Cox

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regression models were used before and after Inverse Probability of Treatment Weighting (IPTW)

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adjustment.

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Results

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Overall, 248 (16.3%) patients treated with PC harboured nonUCUB. Of those, 115 (46.5%) vs. 50

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(20%) vs. 34 (14%) vs. 49 (19.5%) were, respectively, adenocarcinoma vs. squamous carcinoma vs.

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neuroendocrine carcinoma vs. other histological subtypes. Five-year CSM rates after PC were 23%

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vs. 27% vs. 27% vs. 15% vs. 19% for adenocarcinoma vs. squamous carcinoma vs. neuroendocrine

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carcinoma vs. other vs. UCUB, respectively. The comparison between PC in nonUCUB vs. PC in

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UCUB showed higher CSM in nonUCUB patients (HR:1.4;p=0.03). The comparison between PC

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in nonUCUB vs. RC in nonUCUB showed no CSM differences.

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Conclusions

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PC for nonUCUB results in higher mortality than PC for UCUB. However, PC instead of RC in

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select nonUCUB patients does not undermine survival. In consequence, the excess CSM is

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unrelated to cystectomy type, but originates from tumor biology. These results may act as

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generating hypothesis for future trial design.

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Keywords: neuroendocrine carcinoma; adenocarcinoma; squamous carcinoma; other histological subtypes

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Introduction

Partial cystectomy (PC) represents an alternative to radical cystectomy (RC) in well selected

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patients with urothelial carcinoma of the urinary bladder (UCUB) 1. The NCCN Guidelines 2

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recommend that PC should be reserved to patients with ≤cT2 disease, with a solitary lesion and in

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location amenable to segmental resection with adequate negative surgical margins. Moreover, in

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some elderly patients, the morbidity associated with RC may be prohibitive 3,4 and PC outside of

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this definition may be contemplated. Despite adequate data supporting the use of PC in UCUB 5,6,

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virtually no data exist regarding use of PC in patients with variant histology (nonUCUB) 7–11.

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To address this void, we examined PC use in nonUCUB patients and compared cancer-specific

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mortality (CSM) according to PC in UCUB. Moreover, we also tested CSM rates according to PC

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vs. RC in nonUCUB patients. Our analyses were meant to test two specific concepts, namely

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whether CSM is affected by tumor biology, cystectomy type, or both in nonUCUB patients.

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Materials and methods

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Study population

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Within the Surveillance, Epidemiology and End Results (SEER) 12 database (2001–2016),

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we focused on patients aged 18 years or older with histologically confirmed bladder cancer

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(International Classification of Disease for Oncology [ICD-O] site codes C67.0-67.9). Death

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certificate only and autopsy cases were excluded. Patients with urachal location of the tumor (ICD-

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O site code C67.7) were not considered for the analyses. According to NCCN Guidelines 2, only

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patients with T1-2, N0, M0 bladder cancer were considered (n=11,542). Study population consisted

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of two specific cohorts. The first cohort included patients treated with PC (n=1,526) with either

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nonUCUB (n=248; 16.3%) or UCUB (1,278; 83.7%) histology. The second cohort consisted of

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nonUCUB or UCUB patients that were either treated with PC (n=248 and n=1,278) or RC (n=698

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and n= 9,318).

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Variables definition Within the nonUCUB cohort and according to the 2016 World Health Organization (WHO)

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classification of bladder tumors 13, four major histological variants were recognized:

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adenocarcinoma, squamous carcinoma, neuroendocrine carcinoma and other histological subtypes

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(Supplementary Table 1). Demographic characteristics consisted of age, gender, year of diagnosis

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(2001-2006 vs. 2007-2011 vs. 2012-2016), marital status (married, unmarried, unknown), race

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(White, Black, Hispanic, Other) and socioeconomic status (1 quartile vs. 2-3-4 quartile). Tumor

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size, T stage (T1 vs. T2) and rates of chemotherapy and radiation therapy were also considered.

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Statistical analyses Descriptive statistics relied on tests of means and proportions and, respectively, used the t-

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test and the chi-square. Two types of specific comparisons that relied on CSM rates were

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performed. First, PC in nonUCUB was compared to PC in UCUB. Kaplan-Meier plots and

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multivariable Cox regression models tested the effect of histology on CSM before and after Inverse

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Probability of Treatment Weighting (IPTW) adjustment 14. Second, PC was compared to RC in

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nonUCUB and UCUB patients. Here, Inverse Probability of Treatment Weighting (IPTW) was used

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to minimize potential differences that might exist in patients’ characteristics, according to PC vs.

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RC status 14. IPTW adjusted Kaplan-Meier plots graphically depicted the relationship between PC

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and RC on CSM according to histology. Moreover, IPTW adjusted multivariable Cox regression

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models tested the effect of PC vs. RC on CSM within each histological variant. In all analyses,

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IPTW-adjustment relied on the following variables: age, gender, race, socioeconomic status, marital

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status, year of diagnosis, T stage, chemotherapy and radiation therapy administration. R software

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environment was used in all statistical analyses and graphics (version 3.4.3). All tests were two

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sided with a level of significance set at p <0.05.

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Results

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Descriptive analyses

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Within the first cohort that consisted of 1,526 patients treated with PC, 1,278 (83.7%) and

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248 (16.3%) harboured UCUB vs. nonUCUB (Table 1a). Patients with nonUCUB were younger

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(65 vs. 73 years; p<0.001), and more frequently female (39.5% vs. 21.2%; p<0.001) and unmarried

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(40.7% vs. 33.1%; p=0.04). Median (interquartile range [IQR]) tumor size was 34 (20-50) vs. 30

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(20-50) in nonUCUB vs. UCUB, respectively (p=0.2). The percentage of T1 vs. T2 tumors was

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38.7% vs. 61.3% and 45.5% vs. 54.5% in nonUCUB vs. UCUB, respectively (p=0.06). Among

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patients with nonUCUB, 115 (46.5%), 50 (20%), 34 (14%) and 49 (19.5%) harboured

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adenocarcinoma, squamous carcinoma, neuroendocrine carcinoma and other histological subtypes,

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respectively.

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Within the second cohort, 248 (26%) and 698 (74%) patients with nonUCUB were treated with PC

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and RC, respectively (Table 1b). Patients treated with PC had lower median tumor size (34 [20-50]

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vs. 40 [25-53]; p=0.01) and more frequently harboured T1 stage (38.7% vs. 23.8%) vs. less

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frequently harboured T2 stage (61.3% vs. 76.2%; p<0.001). Moreover, nonUCUB patients treated

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with PC less frequently underwent lymph node dissection (39.9% vs. 74.2%; p<0.001) and

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chemotherapy (17.3% vs. 30.7%; p<0.001), but more frequently underwent radiation therapy (7.3%

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vs. 3%; p=0.006).

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Survival analyses between PC nonUCUB and PC UCUB patients Median follow-up time was 42 (IQR: 19-87) and 46 (IQR: 18-88) months for nonUCUB and

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UCUB, respectively. Overall, 68 vs. 439 deaths were recorded during the study period, in

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nonUCUB vs. UCUB. Five-year CSM rates were 23% vs. 19% for nonUCUB vs. UCUB (p=0.3;

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Figure 1a). Moreover, five-year CSM rates were 23% vs. 27% vs. 27% vs. 15% for adenocarcinoma

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vs. squamous carcinoma vs. neuroendocrine carcinoma vs. other histological subtypes (p=0.5;

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Figure 2). In a subgroup analysis of T1 patients, 5-year CSM rates were respectively 15% vs. 13% 8

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for nonUCUB vs. UCUB (p=0.8; Figure 1c). Conversely, in a subgroup analysis of T2 patients, 5-

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year CSM rates were respectively 28%, vs. 24% for nonUCUB vs. UCUB (p=0.3; Figure 1d).

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In multivariable Cox regression models, nonUCUB was associated with higher CSM both before

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(Hazard Ratio [HR]: 1.4, 95% confidence interval [CI]: 1.0-2.0; p=0.03; Table 2a) and after IPTW

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adjustment (HR: 1.3, 95% CI: 1.0-1.6; p=0.04; Table 2b), compared to UCUB. Moreover, in

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multivariable Cox regression models, squamous carcinoma was associated with higher CSM (HR:

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1.7, 95% CI: 1.0-3.2; p=0.04; Table 2c), compared to UCUB. Conversely, adenocarcinoma (HR:

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1.2; 95% CI: 0.8-1.9; p=0.4), neuroendocrine carcinoma (HR: 1.2; 95% CI: 0.6-2.6; p=0.6) and

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other histological subtypes (HR: 1.6; 95% CI: 0.8-3.1; p=0.1) were not associated with higher

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CSM, compared to UCUB.

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Survival analyses between PC and RC for nonUCUB and UCUB patients

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In IPTW adjusted Kaplan-Meier plots focusing on nonUCUB, 5-year CSM rates were

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respectively 23.5% vs. 21% (p=0.9) for patients treated with PC vs. RC (Figure 3a). In IPTW

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adjusted Kaplan-Meier plots focusing on UCUB, 5-year CSM rates were respectively 18% vs. 17%

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(p=0.2) for patients treated with PC vs. RC (Figure 3b). In IPTW adjusted Kaplan-Meier plots

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focusing on adenocarcinoma, 5-year CSM rates were respectively 22% vs. 16% (p=0.9) for patients

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treated with PC vs. RC (Figure 3c). In IPTW adjusted Kaplan-Meier plots focusing on squamous

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carcinoma, 5-year CSM rates were respectively 27% vs. 20% (p=0.2) for patients treated with PC

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vs. RC (Figure 3d). In IPTW adjusted Kaplan-Meier plots focusing on neuroendocrine carcinoma,

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5-year CSM rates were respectively 28% vs. 22% (p=0.5) for patients treated with PC vs. RC

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(Figure 3e). In IPTW adjusted Kaplan-Meier plots focusing on other histological subtypes, 5-year

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CSM rates were respectively 19% vs. 32% (p=0.2) for patients treated with PC vs. RC (Figure 3f).

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In multivariable IPTW adjusted Cox regression models, PC was not associated with higher CSM

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neither in nonUCUB (HR: 1.1, 95% CI: 0.8-1.4; p=0.6), nor in UCUB (HR: 1.0, 95% CI: 0.9-1.1;

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p=0.5), adenocarcinoma (HR: 1.0, 95% CI: 0.6-1.8; p=0.9), squamous carcinoma (HR: 1.6, 95% 9

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CI: 0.9-2.7; p=0.07), neuroendocrine carcinoma (HR: 1.2, 95% CI: 0.6-2.3; p=0.5) or other

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histological subtypes (HR: 0.8, 95% CI: 0.5-1.5; p=0.5), compared to RC.

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Natural history within PC nonUCUB subtypes

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Finally we performed a descriptive analysis of specific variant histology subtypes that were

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treated with PC (Figure 4). Among patients with adenocarcinoma (Figure 4a), 64 (56%), 7 (6%), 1

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(1%), 31 (27%), 8 (7%) and 4 (3%) patients had adenocarcinoma NOS, bronchio-alveolar, clear-

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cell, mucinous, papillary and signet-ring histology, respectively. Of those, 7 (11%), 1 (14%), 7

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(22%), 3 (37.5%) and 3 (75%) patients with adenocarcinoma NOS, bronchio-alveolar, mucinous,

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papillary and signet-ring histology experienced CSM after a median follow-up time of 56 (IQR: 30-

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87) months.

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Among patients with squamous carcinoma (Figure 4b), 47 (94%) and 3 (6%) had squamous NOS

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and papillary histology, respectively. Of those, 11 (24%) patients with squamous NOS histology

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experienced CSM after a median follow-up time of 27 (IQR: 13-59) months.

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Among patients with neuroendocrine carcinoma (Figure 4c), 22 (65%), 10 (30%) and 2 (5%) had

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small cell, carcinoid and paraganglioma histology, respectively. Of those, 4 (19%) and 3 (30%)

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patients with small cell and carcinoid histology experienced CSM after a median follow-up time of

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28 (IQR: 10-98) months.

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Among patients with other histological subtypes (Figure 4d), the following histologies were

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recorded: carcinoma NOS (n=14; 29%), carcinosarcoma (n=7; 14%), fibromatous carcinoma (n=1;

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2%), giant and spindle cell (n=5; 10%), melanoma (n=1; 2%), myomatous carcinoma (n=17; 35%),

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papillary (n=2; 4%), pheocromocytoma (n=1; 2%) and sarcoma (n=1; 2%). Of those, 3 (21%), 1

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(14%), 1 (100%), 1 (100%), 2 (12%), 1 (50%) and 1 (100%) patients with carcinoma NOS,

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carcinosarcoma, fibromatous carcinoma, melanoma, myomatous carcinoma, papillary and

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pheocromocytoma histology experienced CSM after a median follow-up time of 43 (IQR: 17-93)

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months. 10

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Discussion

PC has not been studied in patients with nonUCUB. Based on lack of data on that topic 7–11,

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we performed two separate analyses. First, we compared CSM rates after PC between nonUCUB

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and UCUB. Second, we compared CSM rates after PC vs. RC in nonUCUB patients.

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The first comparison demonstrated that nonUCUB is associated with higher CSM in patients

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treated with PC, compared to UCUB. Moreover, in analyses that were stratified according to

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specific nonUCUB subtypes, higher CSM was recorded, albeit the differences were not significant,

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except for squamous carcinoma. These observations indicate higher mortality after PC in nonUCUB

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patients, relative to their UCUB counterparts, despite most detailed adjustment for the effect of

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patient related differences. Moreover, stratification according to nonUCUB subtype suggests that all

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nonUCUB subtypes confer higher mortality after PC, relative to PC for UCUB. Based on sample

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size considerations, only the comparison between PC in squamous carcinoma vs. PC in UCUB

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resulted in statistically significant differences. Given the novelty of these findings, we cannot

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directly compare these results with similar analyses of previous reports that focused on PC.

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However, some authors examined the effect of nonUCUB on survival in RC cohorts. Within the

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National Cancer Database (NCDB), Vetterlein et al. 15 reported worse overall survival for patients

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with squamous carcinoma and neuroendocrine carcinoma, relative to UCUB. Moschini et al. 16

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showed worse CSM (HR: 1.5) for pure nonUCUB treated with RC, when compared to UCUB.

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Moreover, in several previous institutional RC series 10,17–19, histological variants were associated

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with worse outcomes in univariable, but not in multivariable models.

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Our second comparison focused on PC vs. RC in nonUCUB patients. Here the opposite

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findings were recorded. Specifically, regardless of cystectomy type (PC vs. RC), no CSM

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differences were recorded. Further stratification according to nonUCUB subtype also revealed no

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differences between PC vs. RC in all six histological subtype comparisons. These findings indicate

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that cystectomy type (PC vs. RC) does not affect the treated the natural history of T1-2 nonUCUB

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bladder cancer. Taken together, the results of both analyses indicate that tumor biology, namely 11

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presence of nonUCUB instead of UCUB, increases CSM. However, once the patient is diagnosed

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with nonUCUB, use of PC in properly selected patients is not associated with worse CSM, relative

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to similar nonUCUB patients treated with RC. This implies that similar consideration for PC may

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be given to properly selected nonUCUB patients as much as in properly selected UCUB patients 2.

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Unfortunately, we were not capable of validating these observations after controlling for specific

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information regarding tumor focality, location and/or presence of carcinoma in situ, as

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recommended for UCUB 2. In the last part of our study, we performed a detailed descriptive analysis of nonUCUB

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patients treated with PC, stratified by histological subtypes. These analyses demonstrated important

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variability with respect to CSM within each histological subtype. We identified specific histological

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subgroups within the main histological subtypes that are associated with particularly adverse CSM

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patterns. For example 75% of patients with signet-ring adenocarcinoma died during follow-up 20.

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However, very few of these patients (n=4) were identified within the SEER database 12. Conversely,

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some variant histology subgroups are associated with more favourable prognosis. For example, no

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patient with papillary squamous (n=3), paraganglioma (n=2) 21 or giant and spindle cell carcinoma

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(n=5) died during follow-up. Finally, many variant histology subgroups showed variability with

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respect to prognosis, where some patients have not experienced an event even with long periods of

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observation. In summary, these observations indicate very important variability within specific

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subgroups of nonUCUB. Even though particularly aggressive subgroups were identified, these

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subgroups contained very few observations and recorded outcomes may be affected by small

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sample size and selection biases. Similar considerations need to be made about more favourable

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subgroups. In consequence, even a very large database such as the SEER 12 has limit ability to

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convey specific prognostic information about nonUCUB subtypes beyond indicating that on

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average higher mortality should be expected compared to UCUB. Despite its novelty, our study has limitations. First, as previously stated, the SEER database

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lacks important details regarding specific treatment assignment, such as tumor multifocality or 12

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concomitant carcinoma in situ and also lacks specific patient characteristics that could have

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disqualified some patients either from PC or RC. Second, we were unable to examine specific

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recurrence and progression trends, since this information is not available within the SEER 12. Third,

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the SEER database 12 does not provide central review. Indeed, previous studies showed that

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histological variants are commonly under-recognized in community practice 22,23. Fourth, SEER 12

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represents one of the largest data repositories in the United States. Nonetheless, it represents an

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informative 33% sample of the United States population designed to reflect population

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characteristics and racial distribution. However, partial sampling may invariably result in systematic

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biases and residual confounding relative to the entire population. Unfortunately, no existing data

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repository allows to assess the totality of the United States population.

13

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Conclusion

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PC for nonUCUB results in higher mortality than PC for UCUB. However, PC instead of

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RC in select nonUCUB patients does not undermine survival. In consequence, the excess CSM is

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unrelated to cystectomy type, but originates from tumor biology. These results may act as

286

generating hypothesis for future trial design.

287

14

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Acknowledgments: None

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Funding: This research did not receive any specific grant from funding agencies in the public,

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commercial, or not-for-profit sectors

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References

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Figure legends

364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380

Figure 1. Kaplan-Meier curves depicting cancer-specific survival according to histological subtype (urothelial carcinoma of the urinary bladder [UCUB] vs. variant histology [nonUCUB]) in patients with T1-2N0M0 bladder cancer treated with partial cystectomy and identified within the Surveillance, Epidemiology and End Results database from 2001 to 2016. a) Overall; b) After Inverse Probability of Treatment Weighting (IPTW) adjustment; c) Patients with T1 disease; d) Patients with T2 disease

381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397

Figure 3. Inverse Probability of Treatment Weighting (IPTW) adjusted Kaplan-Meier curves depicting cancer-specific survival according to cystectomy type (radical cystectomy vs. partial cystectomy) in patients with T1-2N0M0 bladder cancer, identified within the Surveillance, Epidemiology and End Results database from 2001 to 2016. a) Variant histology (nonUCUB); b) Urothelial carcinoma of the urinary bladder (UCUB); c) Adenocarcinoma; d) Squamous carcinoma; e) Neuroendocrine carcinoma; f) Other histological subtype

Figure 2. Kaplan-Meier curves depicting cancer-specific survival according to histological subtype (urothelial carcinoma of the urinary bladder [UCUB] vs. Adenocarcinoma vs. Squamous carcinoma vs. Neuroendocrine carcinoma vs. Other histological subtype) in patients with T12N0M0 bladder cancer treated with partial cystectomy and identified within the Surveillance, Epidemiology and End Results database from 2001 to 2016. 95% confidence interval are provided. a) Overall; b) UCUB; c) Adenocarcinoma; d) Squamous carcinoma; e) Neuroendocrine carcinoma; f) Other histological subtype

Figure 4. Graphical representation of time to event sorted by follow up time in patients with T12N0M0 variant histology bladder cancer treated with partial cystectomy and identified within the Surveillance, Epidemiology and End Results database from 2001 to 2016. a) Adenocarcinoma; b) Squamous carcinoma; c) Neuroendocrine carcinoma; d) Other histological subtype BCa: Bladder Cancer; NOS: not otherwise specified

398 399 400

19

Table 1. Descriptive characteristics of 11,542 patients with histologically confirmed bladder cancer, treated with partial cystectomy (PC) or radical cystectomy (RC) and identified within the Surveillance, Epidemiology, and End Results database from 2001 to 2016. A) Patients treated with PC and stratified according to histology: urothelial carcinoma of the urinary bladder (UCUB) vs. variant histology (nonUCUB) B) Patients are stratified according to cystectomy type: PC vs. RC IQR: interquartile range A)

Age at diagnosis (years)

Gender, n (%) Race, n (%)

Marital status, n (%)

Socioeconomic status, n (%) Year of diagnosis, n (%)

Size (mm)

T stage, n (%) Histological subtypes, n (%)

Lymph node dissection, n (%) Chemotherapy, n (%) Radiation therapy, n (%)

Mean Median IQR Male Female Caucasian African-American Other Married Unmarried Unknown 1 quartile 2-3-4 quartile 2001-2006 2007-2011 2012-2016 Mean Median IQR T1 T2 UCUB Adenocarcinoma Squamous carcinoma Neuroendocrine carcinoma Other No Yes No/Unknown Yes No/Unknown Yes

Overall (n=1,526) 70 72 62-80 1,157 (75.8) 369 (24.2) 1,315 (86.2) 121 (7.9) 90 (5.9) 937 (61.4) 524 (34.3) 65 (4.3) 413 (27.1) 1,113 (72.9) 550 (36) 506 (33.2) 470 (30.8) 37 30 20-50 677 (44.4) 849 (55.6) 1,278 (83.7) 115 (7.5) 50 (3.3) 34 (2.2) 49 (3.2) 1,025 (65.2) 501 (34.8) 1,205 (79) 321 (21) 1,443 (94.6) 83 (5.4)

UCUB (n=1,278; 84) 72 73 64-80 1,007 (78.8) 271 (21.2) 1,112 (87) 94 (7.4) 72 (5.6) 802 (62.8) 423 (33.1) 53 (4.1) 347 (27.2) 931 (72.8) 471 (36.9) 422 (33) 385 (30.1) 35.5 30 20-50 581 (45.5) 697 (54.5) 1,278 (100) 0 (0) 0 (0) 0 (0) 0 (0) 846 (66.2) 432 (33.8) 1,000 (78.2) 278 (21.8) 1,213 (94.9) 65 (5.1)

nonUCUB (n=248; 16) 65 65 55-76 150 (60.5) 98 (39.5) 203 (81.9) 27 (10.9) 18 (7.3) 135 (54.4) 101 (40.7) 12 (4.8) 66 (26.6) 182 (73.4) 79 (31.9) 84 (33.9) 85 (34.3) 42.5 34 20-50 96 (38.7) 152 (61.3) 0 (0) 115 (46.5) 50 (20) 34 (14) 49 (19.5) 149 (60.1) 99 (39.9) 205 (82.7) 43 (17.3) 230 (92.7) 18 (7.3)

p-value <0.001

<0.001 0.09

0.04

0.9 0.3

0.2

0.06 <0.001

0.1 0.1 0.2

B)

Age at diagnosis (years)

Gender, n (%) Race, n (%)

Mean Median IQR Male Female Caucasian African-American

UCUB (n=10,596; 92) PC RC (n=1,278; 12) (n=9,318; 88) 72 67 73 64-80 1,007 (78.8) 271 (21.2) 1,112 (87) 94 (7.4)

68 60-75 7,348 (78.9) 1,970 (21.1) 8,407 (90.2) 450 (4.8)

p-value

PC (n=248; 26)

<0.001

65

nonUCUB (n=946; 8) RC (n=698; 74) 66

65 55-76 150 (60.5) 98 (39.5) 203 (81.9) 27 (10.9)

67 59-75 449 (64.3) 249 (35.7) 609 (87.2) 61 (8.7)

0.9 <0.001

p-value 0.2

0.3 0.06

Marital status, n (%)

Socioeconomic status, n (%) Year of diagnosis, n (%)

Size (mm)

T stage, n (%) Histological subtypes, n (%)

Lymph node dissection, n (%) Chemotherapy, n (%) Radiation therapy, n (%)

Other Married

72 (5.6) 802 (62.8)

461 (4.9) 6,118 (65.7)

0.07

18 (7.3) 135 (54.4)

28 (4) 432 (61.9)

0.1

Unmarried Unknown 1 quartile

423 (33.1) 53 (4.1) 347 (27.2)

2,790 (29.9) 410 (4.4) 2,419 (26)

0.4

101 (40.7) 12 (4.8) 66 (26.6)

235 (33.7) 31 (4.4) 194 (27.8)

0.8

2-3-4 quartile 2001-2006

931 (72.8) 471 (36.9)

6899 (74) 2,851 (30.6)

<0.001

182 (73.4) 79 (31.9)

504 (72.2) 217 (31.1)

0.9

2007-2011 2012-2016 Mean Median IQR T1 T2 UCUB

422 (33) 385 (30.1) 35.5 30 20-50 581 (45.5) 697 (54.5) 1,278 (100)

3,120 (33.5) 3,347 (35.9) 40 35 20-50 2,494 (26.8) 6,824 (73.2) 9,318 (100)

84 (33.9) 85 (34.3) 42.5 34 20-50 96 (38.7) 152 (61.3) 0 (0)

249 (35.7) 232 (33.2) 47 40 25-53 166 (23.8) 532 (76.2) 0 (0)

Adenocarcinoma Squamous carcinoma Neuroendocrine carcinoma Other No

0 (0) 0 (0)

0 (0) 0 (0)

115 (46.5) 50 (20)

0 (0)

0 (0)

34 (14)

175 (25.1) 244 (35) 144 (20.6)

0 (0) 846 (66.2)

0 (0) 2,114 (22.7)

<0.001

49 (19.5) 149 (60.1)

135 (19.3) 180 (25.8)

<0.001

Yes No/Unknown

432 (33.8) 1,000 (78.2)

7,204 (77.3) 6,338 (68)

<0.001

99 (39.9) 205 (82.7)

518 (74.2) 484 (69.3)

<0.001

Yes No/Unknown

278 (21.8) 1,213 (94.9)

2,980 (32) 9,213 (98.9)

<0.001

43 (17.3) 230 (92.7)

214 (30.7) 677 (97)

0.006

Yes

65 (5.1)

105 (1.1)

18 (7.3)

21 (3)

0.007

<0.001 1.0

0.01

<0.001 <0.001

Table 2. Multivariable Cox regression models predicting cancer-specific (CSM) and overall mortality (OM), in patients with bladder cancer treated with partial cystectomy and identified within the Surveillance, Epidemiology and End Results database from 2001 to 2016. a) Urothelial carcinoma of the urinary bladder (UCUB) vs. variant histology (nonUCUB) b) UCUB vs. nonUCUB after Inverse Probability of Treatment Weighting (IPTW) c) UCUB vs. adenocarcinoma vs. squamous carcinoma vs. neuroendocrine carcinoma vs. other histological subtype

HR: Hazard ratio CI: confidence interval a)

Histology Age at diagnosis (years) Gender T stage Chemotherapy Radiation therapy

UCUB nonUCUB Female Male T1 T2 No/Unknown Yes No/Unknown Yes

CSM HR (95% CI) p-value Ref. 1.4 (1.0-2.0) 0.03 1.0 (1.0-1.0) <0.001 Ref. 1.0 (0.8-1.3) 0.9 Ref. 1.5 (1.2-2.0) 0.001 Ref. 0.9 (0.7-1.2) 0.5 Ref. 1.6 (1.1-2.9) <0.001

OM HR (95% CI) p-value Ref. 1.1 (0.8-1.4) 0.7 1.1 (1.0-1.1) <0.001 Ref. 1.1 (0.9-1.4) 0.3 Ref. 1.3 (1.1-2.6) 0.006 Ref. 0.8 (0.7-1.1) 0.1 Ref. 1.8 (1.5-2.8) <0.001

b)

Histology Age at diagnosis (years) Gender T stage Chemotherapy Radiation therapy

UCUB nonUCUB

Female Male T1 T2 No/Unknown Yes No/Unknown Yes

CSM HR (95% CI) Ref. 1.3 (1.0-1.6) 1.0 (1.0-1.0) Ref. 1.1 (0.9-1.5) Ref. 1.5 (1.1-1.9) Ref. 1.0 (0.8-1.4) Ref. 1.4 (1.1-2.7)

p-value 0.04 <0.001

0.3 0.003 0.8 <0.001

OM HR (95% CI) Ref. 1.0 (0.8-1.2) 1.1 (1.0-1.1) Ref. 1.2 (0.9-1.5) Ref. 1.3 (1.1-1.6) Ref. 0.9 (0.7-1.1) Ref. 1.8 (1.5-2.8)

p-value 0.9 <0.001

0.08 0.005 0.2 <0.001

c)

Histology

Age (years) Gender T stage Chemotherapy Radiation therapy

UCUB Adenocarcinoma Squamous carcinoma Neuroendocrine carcinoma Other Female Male T1 T2 No/Unknown Yes No/Unknown Yes

CSM HR (95% CI) Ref. 1.2 (0.8-1.9) 1.7 (1.0-3.2) 1.2 (0.6-2.6) 1.6 (0.8-3.1) 1.0 (1.0-1.0) Ref. 1.0 (0.8-1.3) Ref. 1.5 (1.2-2.0) Ref. 0.9 (0.7-1.2) Ref. 1.6 (1.1-2.9)

p-value 0.4 0.04 0.6 0.1 <0.001 0.9 <0.001 0.5 <0.001

OM HR (95% CI) p-value Ref. 0.9 (0.6-1.4) 0.7 1.2 (0.7-2.1) 0.4 0.9 (0.5-1.8) 0.8 1.3 (0.7-2.1) 0.4 1.1 (1.0-1.1) <0.001 Ref. 1.1 (0.9-1.4) 0.3 Ref. 1.3 (1.1-1.6) 0.005 Ref. 0.8 (0.7-1.1) 0.1 Ref. 1.9 (1.3-2.9) <0.001

Supplementary Table 1. Histological subtypes of 1,526 patients with bladder cancer treated with partial cystectomy identified within the Surveillance, Epidemiology, and End Results database from 2001 to 2016, stratified according to International Classification of Disease for Oncology 3 [ICD-O-3] site codes Histological subtypes (n= 1,526) Urothelial carcinoma of the urinary bladder (n= 1,278)

Neuroendocrine carcinoma (n= 34)

Squamous carcinoma (n= 50)

Adenocarcinoma (n= 115)

Other (n= 49)

8120 (TRANSITIONAL CELL CARCINOMA, NOS) 8122 (TRANSITIONAL CELL CARCINOMA, NOS) 8130 (PAPILLARY TRANS. CELL CARCINOMA) 8131 (PAPILLARY TRANS. CELL CARCINOMA) 8020 (CARCINOMA, UNDIFF., NOS) 8082 (LYMPHOEPITHELIAL CARCINOMA) 8041 (SMALL CELL CARCINOMA, NOS) 8240 (CARCINOID TUMOR, MALIGNANT) 8246 (CARCINOID TUMOR, MALIGNANT) 8680 (PARAGANGLIOMA) 8051 (PAPILLARY CARCINOMA, NOS) 8052 (PAPILLARY CARCINOMA, NOS) 8070 (SQUAMOUS CELL CARCINOMA, NOS) 8071 (SQUAMOUS CELL CARCINOMA, NOS) 8140 (ADENOCARCINOMA, NOS) 8144 (ADENOCARCINOMA, NOS) 8255 (BRONCHIOLO-ALVEOLAR ADENOCA) 8260 (PAPILLARY ADENOCARCINOMA, NOS) 8261 (PAPILLARY ADENOCARCINOMA, NOS) 8262 (PAPILLARY ADENOCARCINOMA, NOS) 8263 (PAPILLARY ADENOCARCINOMA, NOS) 8310 (CLEAR CELL ADENOCARCINOMA, NOS) 8480 (MUCINOUS ADENOCARCINOMA) 8481 (MUCINOUS ADENOCARCINOMA) 8490 (SIGNET RING CELL CARCINOMA) 8560 (ADENOSQUAMOUS CARCINOMA) 8010 (CARCINOMA, NOS) 8032 (GIANT & SPINDLE CELL CARCINOMA) 8033 (GIANT & SPINDLE CELL CARCINOMA) 8035 (GIANT & SPINDLE CELL CARCINOMA) 8050 (PAPILLARY CARCINOMA, NOS) 8700 (PHEOCHROMOCYTOMA) 8720 (NEVI & MELANOMAS) 8804 (SARCOMA, NOS) 8830 (FIBROUS HISTIOCYTOMA, MAL.) 8890 (MYOMATOUS NEOPLASMS) 8896 (MYOMATOUS NEOPLASMS) 8980 (CARCINOSARCOMA, NOS)

ICD-0-3 SEER SITE/HISTOLOGY VALIDATION LIST Transitional cell carcinoma, NOS Trans. cell carcinoma, spindle cell Papillary trans. cell carcinoma Transitional cell carcinoma, micropapillary CARCINOMA, UNDIFFERENTIATED, NOS Lymphoepithelial carcinoma SMALL CELL CARCINOMA, NOS CARCINOID TUMOR, MALIGNANT Neuroendocrine carcinoma PARAGANGLIOMA malignant Verrucous carcinoma, NOS Papillary squamous cell carcinoma SQUAMOUS CELL CARCINOMA, NOS Sq. cell carcinoma, keratinizing, NOS ADENOCARCINOMA, NOS Adenocarcinoma, intestinal type Adenocarcinoma with mixed subtypes PAPILLARY ADENOCARCINOMA, NOS Adenocarcinoma in villous adenoma Villous adenocarcinoma Adenocarcinoma in tubulovillous adenoma CLEAR CELL ADENOCARCINOMA, NOS MUCINOUS ADENOCARCINOMA Mucin-producing adenocarcinoma SIGNET RING CELL CARCINOMA ADENOSQUAMOUS CARCINOMA CARCINOMA, NOS Spindle cell carcinoma Pseudosarcomatous carcinoma Carcinoma with osteoclast-like giant cells PAPILLARY CARCINOMA, NOS PHEOCHROMOCYTOMA Malignant melanoma, NOS Epithelioid sarcoma FIBROUS HISTIOCYTOMA, MAL.): Leiomyosarcoma, NOS Myxoid leiomyosarcoma CARCINOSARCOMA, NOS

n 616 15 635 4 3 5 22 1 9 2 1 2 32 15 60 3 7 2 3 1 2 1 23 8 4 1 14 1 3 1 2 1 1 1 1 16 1 7

Supplementary Table 2. Multivariable Cox regression models, performed after Inverse Probability of Treatment Weighting (IPTW), predicting cancer-specific (CSM) and overall mortality (OM), in patients with bladder cancer treated with partial (PC) or radical cystectomy (RC) and identified within the Surveillance, Epidemiology and End Results database from 2001 to 2016. All models were adjusted for age at diagnosis, gender, T stage (T1 vs. T2), as well as chemotherapy and radiation therapy administration. HR: Hazard ratio CI: confidence interval UCUB: urothelial carcinoma of the urinary bladder nonUCUB: variant histology bladder cancer

nonUCUB UCUB Adenocarcinoma Squamous carcinoma Neuroendocrine carcinoma Other histological subtypes

PC vs. RC PC vs. RC PC vs. RC PC vs. RC PC vs. RC PC vs. RC

CSM HR (95% CI) p-value 1.1 (0.8-1.4) 0.6 1.0 (0.9-1.1) 0.5 1.0 (0.6-1.8) 0.9 1.6 (0.9-2.7) 0.07 1.2 (0.6-2.3) 0.5 0.8 (0.5-1.5) 0.5

OM HR (95% CI) p-value 1.0 (0.8-1.3) 0.9 1.0 (0.9-1.1) 0.3 1.1 (0.7-1.7) 0.8 1.3 (0.8-1.9) 0.2 1.1 (0.6-2.0) 0.6 0.9 (0.5-1.5) 0.6

Clinical Practice Points: •

Small scale studies analyzed cancer-specific mortality in patients with variant histology bladder cancer treated with partial cystectomy



In patients treated with partial cystectomy, variant histology bladder cancer was associated with higher cancer-specific mortality, compared to urothelial carcinoma of the urinary bladder



In patients with variant histology of bladder cancer, cystectomy type (namely: partial vs. radical cystectomy) is not associated with worse survival outcomes



Important variability with respect to cancer-specific mortality was recorded within each non urothelial histological subtype



These results may act as generating hypothesis for future trial design