title: Outcomes of squamous histology in bladder cancer: a population-based study.
abstract: OBJECTIVE
  Squamous cell carcinoma (SCC) of the bladder is an uncommon form of bladder cancer. Using a large population-based sample we sought to describe the outcomes of patients with squamous histology and to define the factors that influence prognosis in these patients.
  
  
  METHODS
  All incident cases of bladder cancer in Ontario undergoing cystectomy from 1994 to 2008 were identified. Electronic treatment records and detailed pathologic information were linked to the study data set. Patients were divided into 3 cohorts: pure SCC, urothelial carcinoma (UC) with squamous differentiation (UCSD), and pure UC. Cox modeling was performed to evaluate factors associated with overall survival (OS) and cancer-specific survival (CSS).
  
  
  RESULTS
  There were identified 178, 325, and 2,884 cases of SCC, UCSD, and UC, respectively. The unadjusted 5-year OS for these groups were 33%, 28%, and 34%, respectively. Patients had higher rates of T3/4 disease with SCC (72%) and UCSD (73%) than those with UC (61%, P<0.001). There was no difference in node positivity among groups (20%, 27%, and 25%, P = 0.519). After adjusting for covariates, SCC did not portend a worse survival, at 5 years. However, SCC did result in a more rapid disease trajectory, with survival curves of SCC and UC crossing at the 5-year mark. Adjusted CSS/OS of UCSD was also not significantly different from UC. Among those patients with SCC, factors associated with CSS included age>70 (hazard ratio [HR] = 1.96, 95% CI: 1.16-3.30), T category≥3 (HR = 2.09, 95% CI: 1.24-3.50), N positive disease (HR = 2.59, 95% CI: 1.55-4.32), lymphovascular invasion (HR = 1.98, 95% CI: 1.13-3.47), and positive surgical margins (HR = 2.95, 95% CI: 1.47-5.93).
  
  
  CONCLUSIONS
  After adjusting for patient and disease characteristics, we have found that SCC leads to a more rapid disease course with survival that is equivalent to UC by 5 years.
authors.affiliation: Department of Urology, Queen's University, Kingston, Canada; Department of Oncology, Queen's University, Kingston, Canada; Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Kingston, Canada. Electronic address: izardj@kgh.kari.net.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Izard
authors.affiliation: Department of Urology, Queen's University, Kingston, Canada; Department of Oncology, Queen's University, Kingston, Canada; Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Kingston, Canada.
authors.forename: D Robert
authors.initials: DR
authors.lastname: Siemens
authors.affiliation: Department of Oncology, Queen's University, Kingston, Canada; Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Kingston, Canada; Department of Public Health Sciences, Queen's University, Kingston, Canada.
authors.forename: William J
authors.initials: WJ
authors.lastname: Mackillop
authors.affiliation: Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Kingston, Canada.
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Urology, Queen's University, Kingston, Canada; Department of Oncology, Queen's University, Kingston, Canada.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Leveridge
authors.affiliation: Department of Oncology, Queen's University, Kingston, Canada; Department of Pathology, Queen's University, Kingston, Canada.
authors.forename: David M
authors.initials: DM
authors.lastname: Berman
authors.affiliation: Department of Public Health Sciences, Queen's University, Kingston, Canada; Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Kingston, Canada.
authors.forename: Yingwei
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Oncology, Queen's University, Kingston, Canada; Department of Public Health Sciences, Queen's University, Kingston, Canada; Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, Kingston, Canada.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Booth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology*; D002295:Carcinoma, Transitional Cell / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D001749:Urinary Bladder Neoplasms / Q000401:mortality / Q000473:pathology*; D055815:Young Adult
keywords: Outcomes; Prognosis; Squamous cell carcinoma; Urinary bladder neoplasms