title: National Cancer Data Base/Surveillance Epidemiology and End Results: potential insensitive-measure bias.
abstract: OBJECTIVE
  Abstraction of data from National Cancer Data Base (NCDB)/Surveillance Epidemiology and End Results (SEER) for reasons other than incidence, mortality, and patterns of care has risen. A potential problem with these data is that insensitive-measure bias can exist because of possible inaccuracies in hospital tumor registry staging. The purpose of this study is to assess the accuracy of tumor registry staging from six community hospitals.
  
  
  METHODS
  Staging of 103 consecutive cancers operated on by a gynecologic oncologist (one of the authors) as a surgical consultant to a gynecologist or surgeon was reviewed. Hospital tumor registry staging forms were arbitrarily assigned to be completed by the nongynecologic oncologist versus the gynecologic oncologist by the medical records department. The authors reassessed cancer staging by medical chart review. The tumor registry staging was compared with the actual staging as determined by the authors. Major staging violations were defined as errors that would significantly change stage enough to alter prognosis or change recommended adjuvant treatment. All other violations were defined as minor.
  
  
  RESULTS
  Twenty-eight (27%) cancers were staged by the gynecologic oncologist and 75 (73%) by nongynecologic oncologists. Eighty (78%) cancers were endometrial and 14 (13%) ovarian. Eighty-three (81%) tumors were stage I or II. Major staging violations occurred in 0% of cancers staged by the gynecologic oncologist and 22% (16/75) by a nongynecologic oncologist (P = 0.002). Minor staging violations occurred in 14% (4/28) of cancers staged by the gynecologic oncologist and 42% (32/75) by a nongynecologic oncologist (P = 0. 005). Minor violations were due to omission of histologic subtype and/or grade.
  
  
  CONCLUSIONS
  The 22% major staging violation rate represents significant insensitive-measure bias. If additional studies produce similar results, abstraction of data from NCDB/SEER for reasons other than incidence, mortality, and patterns of care cannot be accepted as evidence-based scientific medicine.
authors.affiliation: Division of Gynecologic Oncology, Medical College of Ohio, Toledo, Ohio 43614-5809, USA.
authors.forename: J
authors.initials: J
authors.lastname: Fanning
authors.forename: A
authors.initials: A
authors.lastname: Gangestad
authors.forename: S J
authors.initials: SJ
authors.lastname: Andrews
mesh_terms: D015982:Bias; D016208:Databases, Factual; D019317:Evidence-Based Medicine; D005260:Female; D005833:Genital Neoplasms, Female / Q000453:epidemiology* / Q000473:pathology; D006764:Hospitals, Community / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D009367:Neoplasm Staging / Q000706:statistics & numerical data*; D015588:Observer Variation; D010818:Practice Patterns, Physicians'; D012042:Registries; D018426:SEER Program / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology