Five ways to improve international comparisons of cancer survival: lessons learned from ICBP SURVMARK-2

Therese M-L Andersson,Mark J Rutherford,Mark J Rutherford,Paul C Lambert,Paul C Lambert,Isabelle Soerjomataram,Bjørn Møller,Melina Arnold,Tor Åge Myklebust,Tor Åge Myklebust,D Maxwell Parkin,D Maxwell Parkin,Freddie Bray

doi:10.1038/s41416-022-01701-0

Abstract

BackgroundComparisons of population-based cancer survival between countries are important to benchmark the overall effectiveness of cancer management. The International Cancer Benchmarking Partnership (ICBP) Survmark-2 study aims to compare survival in seven high-income countries across eight cancer sites and explore reasons for the observed differences. A critical aspect in ensuring comparability in the reported survival estimates are similarities in practice across cancer registries. While ICBP Survmark-2 has shown these differences are unlikely to explain the observed differences in cancer-specific survival between countries, it is important to keep in mind potential biases linked to registry practice and understand their likely impact.MethodsBased on experiences gained within ICBP Survmark-2, we have developed a set of recommendations that seek to optimally harmonise cancer registry datasets to improve future benchmarking exercises.ResultsOur recommendations stem from considering the impact on cancer survival estimates in five key areas: (1) the completeness of the registry and the availability of registration sources; (2) the inclusion of death certification as a source of identifying cases; (3) the specification of the date of incidence; (4) the approach to handling multiple primary tumours and (5) the quality of linkage of cases to the deaths register.ConclusionThese recommendations seek to improve comparability whilst maintaining the opportunity to understand and act upon international variations in outcomes among cancer patients.

Highlights

Comparisons of cancer survival between or within countries, as derived from population-based cancer registry data, have been the subject of a number of large-scale and influential collaborative projects, including the International Cancer Benchmarking Partnership (ICBP) [1,2,3,4]
We draw upon some of the lessons learned from the ICBP Survmark-2 study with respect to registry practices and offer five recommendations that seek to increase data harmonisation so as to improve the comparability of future studies of cancer survival [1,2,3]
Depending on the methodology of the registry, comparing deaths with the file of registered cases may require a “waiting period” to be established, to ensure that all between the date of incidence (DOI) and date of death; the DOI recorded at the registry has some influence on survival source reports are duly received

Summary

Introduction

Comparisons of cancer survival between or within countries, as derived from population-based cancer registry data, have been the subject of a number of large-scale and influential collaborative projects, including the International Cancer Benchmarking Partnership (ICBP) [1,2,3,4]. Depending on the methodology of the registry (e.g. the sources of information available to the Date of incidence registry, and the delay with which information from each source Since cancer patient survival is estimated based on the time arrives), comparing deaths with the file of registered cases may require a “waiting period” to be established, to ensure that all between the date of incidence (DOI) and date of death; the DOI recorded at the registry has some influence on survival source reports are duly received.

Results

Conclusion