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Evidence against the proposition that “UK cancer survival statistics are misleading”: simulation study with National Cancer Registry data

BMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d3399 (Published 09 June 2011) Cite this as: BMJ 2011;342:d3399
  1. Laura M Woods, lecturer in cancer epidemiology1,
  2. Michel P Coleman, professor of epidemiology and vital statistics1,
  3. Gill Lawrence, director2,
  4. Jem Rashbass, director3,
  5. Franco Berrino, director4,
  6. Bernard Rachet, senior lecturer in cancer epidemiology1
  1. 1Cancer Research UK Cancer Survival Group, Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
  2. 2West Midlands Cancer Intelligence Unit, University of Birmingham, Birmingham BT5 2TT, UK
  3. 3Eastern Cancer Registry and Information Centre, Cambridge CB22 3AD, UK
  4. 4Department of Predictive and Preventive Medicine, Fondazione IRCCS, Istituto Nazionale dei Tumori, Milan, Italy
  1. Correspondence to: L M Woods laura.woods{at}lshtm.ac.uk
  • Accepted 18 April 2011

Abstract

Objectives To simulate each of two hypothesised errors in the National Cancer Registry (recording of the date of recurrence of cancer, instead of the date of diagnosis, for registrations initiated from a death certificate; long term survivors who are never notified to the registry), to estimate their possible effect on relative survival, and to establish whether lower survival in the UK might be due to one or both of these errors.

Design Simulation study.

Setting National Cancer Registry of England and Wales.

Population Patients diagnosed as having breast (women), lung, or colorectal cancer during 1995-2007 in England and Wales, with follow-up to 31 December 2007.

Main outcome measure Mean absolute percentage change in one year and five year relative survival associated with each simulated error.

Results To explain the differences in one year survival after breast cancer between England and Sweden, under the first hypothesis, date of diagnosis would have to have been incorrectly recorded by an average of more than a year for more than 70% of women known to be dead. Alternatively, under the second hypothesis, failure to register even 40% of long term survivors would explain less than half the difference in one year survival. Results were similar for lung and colorectal cancers.

Conclusions Even implausibly extreme levels of the hypothesised errors in the cancer registry data could not explain the international differences in survival observed between the UK and other European countries.

Footnotes

  • Contributors: LMW did all the analyses, interpreted the results, and co-wrote the manuscript. MPC had strategic input into analyses, interpreted the results, and co-wrote the manuscript. GL, JR, and FB contributed to the interpretation of the analyses and commented on the manuscript. BR conceived the study, assisted with the analyses, interpreted the results, and co-wrote the manuscript. All authors had full access to the results of all analyses. LMW, MPC, and BR are the guarantors.

  • Funding: None.

  • Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The Medical Research Division at the Office for National Statistics gave permission for the use of data from the National Cancer Registry data for England and Wales; the ethics committee at the London School of Hygiene and Tropical Medicine approved the study.

  • Data sharing: No additional data available.

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