Development and Validation of a Novel Recurrence Risk Stratification for Initial Non-muscle Invasive Bladder Cancer in Asia.
BACKGROUND
Some risk classifications to determine prognosis of patients with non-muscle invasive bladder cancer (NMIBC) have disadvantages in the clinical setting. We investigated whether the EORTC (European Organization for Research and Treatment of Cancer) risk stratification is useful to predict recurrence and progression in Japanese patients with NMIBC. In addition, we developed and validated a novel, and simple risk classification of recurrence.


METHODS
The analysis was based on 1085 patients with NMIBC at six hospitals. Excluding recurrent cases, we included 856 patients with initial NMIBC for the analysis. The Kaplan-Meier method with the log-rank test were used to calculate recurrence-free survival (RFS) rate and progression-free survival (PFS) rate according to the EORTC risk classifications. We developed a novel risk classification system for recurrence in NMIBC patients using the independent recurrence prognostic factors based on Cox proportional hazards regression analysis. External validation was done on an external data set of 641 patients from Kyorin University Hospital.


RESULTS
There were no significant differences in RFS and PFS rates between the groups according to EORTC risk classification. We constructed a novel risk model predicting recurrence that classified patients into three groups using four independent prognostic factors to predict tumour recurrence based on Cox proportional hazards regression analysis. According to the novel recurrence risk classification, there was a significant difference in 5-year RFS rate between the low (68.4%), intermediate (45.8%) and high (33.7%) risk groups (P<0.001).


CONCLUSIONS
As the EORTC risk group stratification may not be applicable to Asian patients with NMIBC, our novel classification model can be a simple and useful prognostic tool to stratify recurrence risk in patients with NMIBC.


BACKGROUND
None.
Department of Urology, Juntendo University, Graduate School of Medicine, Japan.
Takeshi
T
Ieda
Department of Urology, Teikyo University, School of Medicine, Japan.
Satoru
S
Muto
Department of Urology, Juntendo Nerima Hospital, Japan.
Fumitaka
F
Shimizu
Department of Biostatistics, Yokohama City University, School of Medicine, Japan.
Masataka
M
Taguri
Department of Urology, Juntendo Urayasu Hospital, Japan.
Shigeto
S
Yanada
Department of Urology, Juntendo University, Graduate School of Medicine, Japan.
Kousuke
K
Kitamura
Department of Urology, Teikyo University, School of Medicine, Japan.
Kazutaka
K
Terai
Department of Urology, Teikyo University, School of Medicine, Japan.
Keisuke
K
Saito
Department of Urology, Tokushukai Hospital, Chiba, Japan.
Tatsuya
T
Ogishima
Department of Urology, Juntendo University, Graduate School of Medicine, Japan.
Masayoshi
M
Nagata
Department of Urology, Teikyo University, School of Medicine, Japan.
Hisamitsu
H
Ide
Department of Urology, Kyorin University School of Medicine.
Takatsugu
T
Okegawa
Department of Urology, Juntendo University, Graduate School of Medicine, Japan.
Yoshiaki
Y
Wakumoto
Department of Urology, Juntendo Nerima Hospital, Japan.
Yoshiro
Y
Sakamoto
Department of Urology, Juntendo Urayasu Hospital, Japan.
Akira
A
Tsujimura
Department of Urology, Teikyo University, School of Medicine, Japan.
Raizo
R
Yamaguchi
Department of Urology, Kyorin University School of Medicine.
Kikuo
K
Nutahara
Department of Urology, Juntendo University, Graduate School of Medicine, Japan. Electronic address: shorie@juntendo.ac.jp.
Shigeo
S
Horie
D000368:Aged; D001208:Asia / Q000453:epidemiology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology* / Q000628:therapy
Classification; Non-muscle invasive bladder cancer; Recurrence; Risk factor