title: Histological confirmation of breast cancer registration and self-reporting in England and Wales: a cohort study within the UK Collaborative Trial of Ovarian Cancer Screening.
abstract: BACKGROUND
  In research studies, accurate information of cancer diagnosis is crucial. In women with breast cancer (BC), we compare cancer registration (CR) in England/Wales and self-reporting with independent confirmation.
  
  
  METHODS
  In the UK Collaborative Trial of Ovarian Cancer Screening, notification of BC diagnosed between randomisation and 31 December 2009 was obtained through (1) CR (17 October 2011) and (2) self-reporting using postal-questionnaire. Breast cancer was confirmed using a detailed questionnaire (BC questionnaire BCQ) completed by the treating clinician (gold standard). Apparent sensitivity and positive-predictive value of CR/self-reporting vs BCQ were calculated.
  
  
  RESULTS
  Of 1065 women with possible BC notification, diagnosis was confirmed in 932 (87.5%). A total of 3.1% (28 out of 918) of BC CR and 12.4% (128 out of 1032) of women with self-reported BC only had in-situ carcinoma on BCQ. Another 4.6% (43 out of 932) of BCQ-confirmed cancer did not have a BC registration, and 3.6% (34 out of 932) did not self-report BC. Apparent sensitivity of CR and self-reporting vs BCQ were 95.4 and 96.4%, respectively. Positive-predictive value of self-reporting (87.1%) was significantly lower than that of CR (96.8%). Women aged<65 were more likely to over report in-situ carcinoma as BC. Overall, 73 (6.8%) women would have been misclassified/missed if CR, and 167 (15.6%) if self-reporting data alone was used.
  
  
  CONCLUSIONS
  This study confirms the reliability of BC registration in England/Wales and highlights the fact that 1 in 10 women self-reporting BC might only have in-situ breast carcinoma.
authors.affiliation: Gynaecological Cancer Research Centre, UCL EGA Institute for Women's Health, University College London, UK.
authors.forename: E O
authors.initials: EO
authors.lastname: Fourkala
authors.forename: A
authors.initials: A
authors.lastname: Gentry-Maharaj
authors.forename: M
authors.initials: M
authors.lastname: Burnell
authors.forename: A
authors.initials: A
authors.lastname: Ryan
authors.forename: R
authors.initials: R
authors.lastname: Manchanda
authors.forename: A
authors.initials: A
authors.lastname: Dawnay
authors.forename: I
authors.initials: I
authors.lastname: Jacobs
authors.forename: M
authors.initials: M
authors.lastname: Widschwendter
authors.forename: U
authors.initials: U
authors.lastname: Menon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000473:pathology; D015331:Cohort Studies; D004739:England; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D012042:Registries; D057566:Self Report; D011795:Surveys and Questionnaires; D014852:Wales