Michael Eden1, Samantha Harrison2, Michelle Griffin3, Mats Lambe4, David Pettersson5, Anna Gavin6, David H Brewster7, Yulan Lin8, Tom B Johannesen9, Roger L Milne10, Helen Farrugia11, Diane Nishri12, Mary-Jane King13, Dyfed W Huws14, Janet Warlow15, Donna Turner16, Craig C Earle17, Michael Peake18, Jem Rashbass19. 1. National Cancer Registry and Analysis Service (NCRAS), England, UK. Electronic address: Michael.Eden@phe.gov.uk. 2. Policy and Information, Cancer Research UK, England, UK. Electronic address: Samantha.harrison@cancer.org.uk. 3. National Disease Registration, Public Health England, England, UK. Electronic address: michelle.griffin@phe.gov.uk. 4. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Sweden. Electronic address: mats.lambe@ki.se. 5. National Board of Health and Welfare, Stockholm, Sweden. Electronic address: david.pettersson@socialstyrelsen.se. 6. N. Ireland Cancer Registry, Queen's University Belfast, Northern Ireland, UK. Electronic address: a.gavin@qub.ac.uk. 7. Scottish Cancer Registry, NHS National Services Scotland, Scotland, UK. Electronic address: David.H.Brewster@ed.ac.uk. 8. European Palliative Care Research Centre (PRC), Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Norway. Electronic address: yulan.lin@ntnu.no. 9. Cancer Registry of Norway, Oslo, Norway. Electronic address: tom.borge.johannesen@kreftregisteret.no. 10. Cancer Epidemiology and Intelligence Division, Cancer Council Victoria, Melbourne, Australia. Electronic address: roger.milne@cancervic.org.au. 11. Victorian Cancer Registry, Cancer Council Victoria, Melbourne, Australia. Electronic address: helen.farrugia@cancervic.org.au. 12. Prevention and Cancer Control, Cancer Care Ontario, Ontario, Canada. Electronic address: Diane.Nishri@cancercare.on.ca. 13. Ontario Cancer Registry, Cancer Care Ontario, Ontario, Canada. Electronic address: MaryJane.King@cancercare.on.ca. 14. Welsh Cancer Intelligence and Surveillance Unit, Public Health Wales, Wales, UK. Electronic address: dyfed.huws@wales.nhs.uk. 15. Welsh Cancer Intelligence and Surveillance Unit, Public Health Wales, Wales, UK. Electronic address: janet.warlow@wales.nhs.uk. 16. Epidemiology and Cancer Registry, CancerCare Manitoba, Manitoba, Canada. Electronic address: Donna.Turner@cancercare.mb.ca. 17. Institute for Clinical Evaluative Sciences, Ontario Institute for Cancer Research, Ontario, Canada. Electronic address: Craig.Earle@partnershipagainstcancer.ca. 18. Respiratory Medicine, University of Leicester and National Cancer Registration and Analysis Service (NCRAS), England, UK. Electronic address: mick.peake@uhl-tr.nhs.uk. 19. National Disease Registration, Public Health England, England, UK. Electronic address: Jem.Rashbass@phe.gov.uk.
Abstract
BACKGROUND: International cancer survival comparisons use cancer registration data to report cancer survival, which informs the development of cancer policy and practice. Studies like the International Cancer Benchmarking Partnership (ICBP) have a duty to understand how registration differences impact on survival prior to drawing conclusions. METHODS: Key informants reported differences in registration practice for capturing incidence date, death certificate case handling and registration of multiple primary tumours. Sensitivity analyses estimated their impact on one-year survival using baseline and supplementary cancer registration data from England and Sweden. RESULTS: Variations in registration practice accounted for up to a 7.3 percentage point difference between unadjusted (estimates from previous ICBP survival data) and adjusted (estimates recalculated accounting for registration differences) one-year survival, depending on tumour site and jurisdiction. One-year survival estimates for four jurisdictions were affected by adjustment: New South Wales, Norway, Ontario, Sweden. Sweden and Ontario's survival reduced after adjustment, yet they remained the jurisdictions with the highest survival for breast and ovarian cancer respectively. Sweden had the highest unadjusted lung cancer survival of 43.6% which was adjusted to 39.0% leaving Victoria and Manitoba with the highest estimate at 42.7%. For colorectal cancer, Victoria's highest survival of 85.1% remained unchanged after adjustment. CONCLUSION: Population-based cancer survival comparisons can be subject to registration biases that may impact the reported 'survival gap' between populations. Efforts should be made to apply consistent registration practices internationally. In the meantime, survival comparison studies should provide acknowledgement of or adjustment for the registration biases that may affect their conclusions.
BACKGROUND: International cancer survival comparisons use cancer registration data to report cancer survival, which informs the development of cancer policy and practice. Studies like the International Cancer Benchmarking Partnership (ICBP) have a duty to understand how registration differences impact on survival prior to drawing conclusions. METHODS: Key informants reported differences in registration practice for capturing incidence date, death certificate case handling and registration of multiple primary tumours. Sensitivity analyses estimated their impact on one-year survival using baseline and supplementary cancer registration data from England and Sweden. RESULTS: Variations in registration practice accounted for up to a 7.3 percentage point difference between unadjusted (estimates from previous ICBP survival data) and adjusted (estimates recalculated accounting for registration differences) one-year survival, depending on tumour site and jurisdiction. One-year survival estimates for four jurisdictions were affected by adjustment: New South Wales, Norway, Ontario, Sweden. Sweden and Ontario's survival reduced after adjustment, yet they remained the jurisdictions with the highest survival for breast and ovarian cancer respectively. Sweden had the highest unadjusted lung cancer survival of 43.6% which was adjusted to 39.0% leaving Victoria and Manitoba with the highest estimate at 42.7%. For colorectal cancer, Victoria's highest survival of 85.1% remained unchanged after adjustment. CONCLUSION: Population-based cancer survival comparisons can be subject to registration biases that may impact the reported 'survival gap' between populations. Efforts should be made to apply consistent registration practices internationally. In the meantime, survival comparison studies should provide acknowledgement of or adjustment for the registration biases that may affect their conclusions.
Authors: Melina Arnold; Mark J Rutherford; Aude Bardot; Jacques Ferlay; Therese M-L Andersson; Tor Åge Myklebust; Hanna Tervonen; Vicky Thursfield; David Ransom; Lorraine Shack; Ryan R Woods; Donna Turner; Suzanne Leonfellner; Susan Ryan; Nathalie Saint-Jacques; Prithwish De; Carol McClure; Agnihotram V Ramanakumar; Heather Stuart-Panko; Gerda Engholm; Paul M Walsh; Christopher Jackson; Sally Vernon; Eileen Morgan; Anna Gavin; David S Morrison; Dyfed W Huws; Geoff Porter; John Butler; Heather Bryant; David C Currow; Sara Hiom; D Max Parkin; Peter Sasieni; Paul C Lambert; Bjørn Møller; Isabelle Soerjomataram; Freddie Bray Journal: Lancet Oncol Date: 2019-09-11 Impact factor: 41.316