title: Predicting results of daily-practice cystoscopies.
abstract: OBJECTIVE
  Our objective was to elaborate a predictive model of bladder cancer, in an unselected clinical population submitted to cystoscopy.
  
  
  METHODS
  We recruited consecutive patients that underwent cystoscopy due to suspicion of bladder cancer or surveillance of a previously diagnosed bladder cancer. Urine cytology and a BTA-stat® (BTA) test were carried out for all patients. To avoid an assessment bias, the BTA-tests, cytologies and cystoscopies were conducted in a blinded fashion. We used logistic regression to predict cystoscopy results from cytology, BTA-test and clinical variables.
  
  
  RESULTS
  From August 2011 to July 2012, we recruited 244 patients and 237 were valid for analysis. Newly diagnosed and surveillance cases were 13% and 87% respectively. Cytology and BTA-test sensitivities were 57.9% (CI 95: 42.2-72.1) and 63.2% (CI 95: 47.3-76.6) with specificities of 84.4% (CI 95: 78.7-88.8) and 82.9% (CI 95: 77.1-87.5). The predictive model included the BTA-test, cytology, time since previous tumour, and treatment with mitomicin or BGC during the last three months. The model predictive accuracy (AUC) was .85 (.78-.92), and dropped to 0.79 when excluding the BTA-test (P=.026). For the surveillance of bladder cancer, a 10% threshold on the model predicted probabilities resulted in an overall negative predictive value of 95.7%, and 95.0% in low grade tumours.
  
  
  CONCLUSIONS
  In a cost containment environment, our prediction model could be used to space out cystoscopies in patients with previous, low grade tumours, resulting in a more efficient use of resources in the healthcare system.
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: F
authors.initials: F
authors.lastname: García-Velandria
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: J F
authors.initials: JF
authors.lastname: Sánchez-García
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: L A
authors.initials: LA
authors.lastname: Rodríguez-Toves
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: L
authors.initials: L
authors.lastname: Alvarez-Buitrago
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: C
authors.initials: C
authors.lastname: Conde-Redondo
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: V
authors.initials: V
authors.lastname: Rodríguez-Tesedo
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: J H
authors.initials: JH
authors.lastname: Amón-Sesmero
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: M
authors.initials: M
authors.lastname: Cepeda-Delgado
authors.affiliation: Unidad de Bioestadística, Departamento de Salud Pública, Universidad de Barcelona y Saalig Clinical, SL, Barcelona, España. Electronic address: acobos@ub.edu.
authors.forename: A
authors.initials: A
authors.lastname: Cobos-Carbó
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: D
authors.initials: D
authors.lastname: Alonso-Fernández
authors.affiliation: Servicio de Urología, Hospital Universitario Río Hortega, Valladolid, España.
authors.forename: J M
authors.initials: JM
authors.lastname: Martínez-Sagarra
mesh_terms: D000368:Aged; D003558:Cystoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011379:Prognosis; D001749:Urinary Bladder Neoplasms / Q000473:pathology*
keywords: Cistoscopia; Cystoscopy; Cytological techniques; Cáncer de vejiga urinaria; Genitourinary neoplasm; Marcadores tumorales; Neoplasias genitourinarias; Nomogramas; Nomograms; Tumor markers; Técnicas Citológicas; Urinary bladder cancer