The impact of life tables on age standardized net survival of real-life example databases.

Background: Population-based, age-standardized net survival estimates provide valuable insights for comparing the effectiveness of cancer treatment and the prospects of cure in an international context. Although numerous studies have previously assessed survival, the choice of life tables may crucially impact the feasibility of such analyses. Therefore, based on available studies, our aim was to understand the critical influence of life tables on net survival estimates.

Methods: Record-level data of approximately 50,000 breast, cervical, and ovarian cancer patients were extracted from the Hungarian National Cancer Registry. These patients were diagnosed between 2010 and 2014 and were followed up until December 31, 2019. Life tables for the Hungarian female population were taken from the Human Mortality Database, the Human Life-Table Database and were compiled according to the EUROCARE, CONCORD both multivariable flexible and Ewbank methodology. Regarding the last due to the lack of specific parameters, simulations were performed to assess the missing values​. The calculation of 5-year age-standardized net survival using different life tables revealed limitations in the methodology, highlighting the impact of life table selection on survival estimates.

Findings: Minor biases were observed in age-standardized net survival when using life tables from different international databases. However, the net survival of breast cancer, which had the most favorable prognosis of the studied malignancies, showed significant discrepancies. Moreover, this research highlights the extreme sensitivity of the applied κ parameter in the CONCORD Ewbank method, underscoring the need for careful consideration when applying this approach.

Interpretation: Present study shed light on how the choice of life tables can lead to differences in survival estimates for the same cancer population. It also emphasizes the importance of open methodological discussions to improve validity and accuracy of international comparability.