1. Dr Heather O Dickinson My web page Department of Child Health University of Newcastle My web page Audit of cancer registrations notified by National Health Service Central Register in England & Wales

2. I work on the epidemiology of children’s cancer, mainly on cohort studies in relation to exposures around birth: Heather Dickinson population mixing infections father’s preconceptional irradiation

3. l Learning objectives - understand:  importance of ascertainment of cases from multiple sources  importance of diagnostic review  age - cohort effects l Performance objectives - able to:  use capture-recapture methods  organise a diagnostic review

4. 12 regional cancer registries National Health Service Central Register (NHSCR) Cancer registration system in England & Wales

5. No. of cancers Year of diagnosis Notified by NHSCR Expected 197119751980198519901993 0 20 40 60 80 100 Cancers notified by NHSCR

6. l Accuracy of diagnoses Were site and type codes correct? l Completeness of ascertainment Did they tell us about ALL the people who got cancer? Objective For NHSCR cancer registrations, 1971-89, to assess:

7. Accuracy of diagnostic codes from NHSCR

8. Identify hospital of diagnosis Request biopsy, pathology or post-mortem report Request clinical records Review cancer or death registration Material found and satisfactory? Hospital ID no. known? Clinical records obtained? Yes No Review complete

9. Pathology review of NHSCR cancer registrations

10. Diagnostic groups l we used 13 standard groups for children’s cancer Kramarova et al., 1996 l we added 3 groups for adult cancer We grouped the cancers into diagnostic groups:

11. Level of agreement between diagnostic codes of NHSCR and review

12. Reasons for disagreement

13. l age l how recently the original diagnosis was made Reasons for disagreement We were interested in whether the accuracy of diagnosis depended on:

14. Total no. in cohort Year 19711975198019851989 0 50,000 100,000 The Cumbrian birth cohort 0-14 yrs 15-24 yrs over 25 yrs

15. 0 4 8 12 0-1415-24over 25 Age (in years) at diagnosis % of cases NHSCR and review diagnoses in different groups p for heterogeneity = 0.03

16. 0 4 8 12 1971-741975-791980-841985-89 Time period of diagnosis % of cases NHSCR and review diagnoses in different groups p for trend = 0.07

17. Completeness of ascertainment by NHSCR Did NHSCR tell us about all the people in our cohort who got cancer?

18. Completeness of ascertainment by NHSCR *N = No. of cancers not notified by NHSCR

19. Completeness of ascertainment by NHSCR l 720 cases notified by NHSCR  694 confirmed as malignant l 740 malignancies notified from all sources Ascertainment = 694/740 = 94%

20. % of cases missed Completeness of ascertainment by NHSCR p for heterogeneity = 0.02 0-1415-24over 25 Age (in yrs) at diagnosis 0 4 8 12

21. 0 2 4 6 8 1971-741975-791980-841985-89 % of cases missed p for trend = 0.83 Time period of diagnosis Completeness of ascertainment by NHSCR

22. Other cases? l Not notified by NHSCR AND l Not notified by any other source

23. Notified by NHSCR? YesNo NotifiedYes 21511 by other sources? No ? Cases not notified by NHSCR or other sources Over 25 years 86

24. Notified by NHSCR? YesNo NotifiedYes 19415 by other sources? No ? Cases not notified by NHSCR or other sources 15 - 24 years 24

25. Notified by NHSCR? YesNo NotifiedYes 1750 by other sources? No ? Cases not notified by NHSCR or other sources 0 - 14 years 86

26. Cancers missed by NHSCR Notified by other sources?TOTAL Age at diagnosis YESNO n (%) 0-14 20 0.0 20.0 (10%) 15-24 151.9 16.9 (7%) over 25 11 4.4 14.4 (5%) ALL AGES 466.351.3 (7%) (in years)

27. Summary: completeness of ascertainment by NHSCR l NHSCR definitely missed 46 (6%) out of 740 cases notified by all sources. l NHSCR probably missed more cases which were not notified to us by any source.

28. l NHSCR missed 10% of cases in the youngest age group. NHSCR probably missed at least 10% of cases in other age groups too. Summary: completeness of ascertainment by NHSCR

29. Conclusions l Ascertainment from multiple sources & l Diagnostic review are essential for epidemiological studies of cancer