title: Low Grade Micropapillary Urothelial Carcinoma, Does It Exist? - Analysis of Management and Outcomes from the Surveillance, Epidemiology and End Results (SEER) Database.
abstract: OBJECTIVE
  To elucidate the oncologic behavior of Micropapillary Urothelial Bladder Carcinoma (MPBC), a rare aggressive variant histology.
  
  
  METHODS
  All MPBC patients in SEER 17 database were compared with those with traditional urothelial carcinoma (UC). Kaplan-Meier curves were used to determine OS and CSS. A Cox proportional hazards model (CPH) was constructed to test the effect of covariates on outcomes.
  
  
  RESULTS
  From 2001-2008, 120 MPBC patients were identified, 0.1% of all bladder cancer. MPBC presented with more high grade (86.1% vs. 38.7%, p<0.0001) and more high stage disease (40.8% NMI vs. 90.4% NMI, p < 0.0001) than UC. Low grade (LG) NMI MPBC had worse OS and CSS compared to LG UC (p=0.0037, p<0.0001 respectively), and did no better than high grade (HG) NMI MPBC. No difference was detected between HG NMI MPBC and HG NMI UC pts. A CPH model controlling for stage, grade, treatment, age, race, and sex detected no significant survival difference in MPBC vs. UC (HR 1.04, p=0.7966). For NMI MPBC (n=49), only 4 patients underwent definitive therapy, of whom none died of disease. However, in those not receiving definitive therapy (n=45), 7 cancer specific deaths occurred (15.6%).
  
  
  CONCLUSIONS
  Controlling for stage and grade, no survival difference could be detected between MPBC and UC. Low grade NMI MPBC behaved similarly to both high grade MPBC and high grade UC. We propose that all MPBC (regardless of grade) be managed as high grade disease, and that strong consideration for definitive therapy should be given in all cases.
authors.affiliation: 1. Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Vourganti
authors.forename: Andrew
authors.initials: A
authors.lastname: Harbin
authors.forename: Eric A
authors.initials: EA
authors.lastname: Singer
authors.forename: Brian
authors.initials: B
authors.lastname: Shuch
authors.forename: Adam R
authors.initials: AR
authors.lastname: Metwalli
authors.forename: Piyush K
authors.initials: PK
authors.lastname: Agarwal
keywords: SEER; bladder; carcinoma; grade; micropapillary