title: Comparison of outcomes following a cytological or histological diagnosis of malignant mesothelioma.
abstract: BACKGROUND
  Survival with the epithelioid subtype of malignant mesothelioma (MM) is longer than the biphasic or sarcomatoid subtypes. There is concern that cytology-diagnosed epithelioid MM may underdiagnose the biphasic subtype. This study examines survival differences between patients with epithelioid MM diagnosed by cytology only and other subtypes diagnosed by histology.
  
  
  METHODS
  Demographics, diagnosis method, MM subtype and survival were extracted from the Western Australia (WA) Mesothelioma Registry, which records details of all MM cases occurring in WA.
  
  
  RESULTS
  A total of 2024 MM cases were identified over 42 years. One thousand seven hundred forty-four (86.2%) were male, median (IQR) age was 68.6 (60.4-77.0) years. A total of 1212 (59.9%) cases were identified as epithelioid subtype of which 499 (41.2%) were diagnosed using fluid cytology only. Those with a cytology-only diagnosis were older than the histology group (median 70.2 vs 67.6 years, P<0.001), but median survival was similar (cytology 10.6 (5.5-19.2) vs histology 11.1 (4.8-19.8) months, P=0.727) and Cox regression modelling adjusting for age, sex, site and time since first exposure showed no difference in survival between the different diagnostic approaches.
  
  
  CONCLUSIONS
  Survival of cytologically and histologically diagnosed epithelioid MM cases does not differ. A diagnostic tap should be considered adequate to diagnose epithelioid MM without need for further invasive testing.
authors.affiliation: Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia.|School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia.|Institute for Respiratory Health, Perth, WA, Australia.
authors.forename: Sanjeevan
authors.initials: S
authors.lastname: Muruganandan
authors.affiliation: School of Public Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia.
authors.forename: Helman
authors.initials: H
authors.lastname: Alfonso
authors.affiliation: School of Population Health, University of Western Australia, Perth, WA, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Franklin
authors.affiliation: PathWest, Queen Elizabeth II Medical Centre, Perth, WA, Australia.
authors.forename: Keith
authors.initials: K
authors.lastname: Shilkin
authors.affiliation: PathWest, Queen Elizabeth II Medical Centre, Perth, WA, Australia.
authors.forename: Amanda
authors.initials: A
authors.lastname: Segal
authors.affiliation: School of Population Health, University of Western Australia, Perth, WA, Australia.
authors.forename: Nola
authors.initials: N
authors.lastname: Olsen
authors.affiliation: School of Public Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia.
authors.forename: Alison
authors.initials: A
authors.lastname: Reid
authors.affiliation: School of Population Health, University of Western Australia, Perth, WA, Australia.|Telethon Kids Institute, University of Western Australia, Perth, WA, Australia.
authors.forename: Nick
authors.initials: N
authors.lastname: de Klerk
authors.affiliation: Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia.|School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia.|School of Population Health, University of Western Australia, Perth, WA, Australia.
authors.forename: Aw Bill
authors.initials: AB
authors.lastname: Musk
authors.affiliation: Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia.|Institute for Respiratory Health, Perth, WA, Australia.|Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, WA, Australia.
authors.forename: Fraser
authors.initials: F
authors.lastname: Brims
mesh_terms: D000368:Aged; D003581:Cytodiagnosis / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008175:Lung Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D008297:Male; D008654:Mesothelioma / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D009367:Neoplasm Staging; D010997:Pleural Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D011379:Prognosis; D012042:Registries; D015996:Survival Rate; D014904:Western Australia