TNM stage in the Nordic Cancer Registries 2004-2016: Registration and availability

Area of Science:

• Oncology
• Epidemiology
• Public Health

Background:

• Cancer stage at diagnosis is a critical determinant of patient survival.
• The TNM (Tumor, Node, Metastasis) staging system is essential for cancer classification, treatment planning, and surveillance.
• Understanding TNM stage distribution is vital for monitoring cancer trends and outcomes.

Purpose of the Study:

• To assess the availability and trends of TNM stage data in Nordic countries.
• To evaluate the comparability and distribution of TNM stage across different periods and cancer types.
• To examine the relationship between TNM stage and 1-year relative survival to gauge registration quality.

Main Methods:

• Utilized TNM data from cancer registries in Denmark, Norway, Sweden, and Iceland (2004-2016).
• Analyzed data for 26 cancer sites (3 countries) and 4 cancer sites (Iceland) across three time periods.
• Employed a validated algorithm for TNM stage imputation and assessed 1-year relative survival for specific cancer types.

Main Results:

• TNM stage availability ranged from 75-95% in Denmark, Sweden, and Iceland, with lower proportions in Norway.
• TNM stage proportions showed an increasing trend in Sweden and a decreasing trend in Denmark over time.
• One-year relative survival varied significantly more by TNM stage than by country, supporting consistent stage recording.

Conclusions:

• TNM stage assessment and registration are crucial for evaluating cancer survival trends in the Nordic region.
• The TNM system effectively predicts survival, with variations primarily linked to stage rather than country-specific registration differences.
• Consistent TNM stage recording across Nordic countries facilitates reliable cancer surveillance and epidemiological studies.