Survival in Lung Cancer in the Nordic Countries Through A Half Century

Abstract

Objective

Lung cancer is often diagnosed at an advanced stage and survival has been poor, although long-term studies have been rare. We analyzed data on survival in lung cancer from Denmark, Finland, Norway, and Sweden over a 50-year period (1971–2020).

Methods

Relative 1- and 5-year survival data were obtained from the NORDCAN database for 1971–2020. We used generalized additive models to estimate survival trends over time and uncertainty of these estimates. We additionally calculated conditional survival from the 1st to 5th year (5/1-year), estimated annual changes in survival rates, and determined significant breaking points.

Results

In 2016–2020, 5-year survival rate for lung cancer was best for Norwegian men (26.6%) and women (33.2%). The sex difference was significant and it was found for each country. Survival improved modestly until the year 2000, after which time survival curves increased steeply and kept the linear shape to the end of follow-up, indicating consistent improvement in survival. Survival curves for 1- and 5/1-year survival were almost superimposable, indicating that deaths in the first year were approximately as many as in the subsequent 4 years, thus marking sustained long-term survival.

Conclusion

We could document a positive development in lung cancer survival with steep upward trends after the year 2000. Intensions for curative treatment have been increasing and the outcomes have been improving with the help of novel imaging methods. Pathways for facile patient access to treatment have been instituted. Close to 90% of the patients are ever smokers. National anti-smoking acts and alerting people who smoke about early symptoms may be beneficial, as metastatic lung cancer remains difficult to cure.

Keywords:

• smoking
• lung cancer
• relative survival
• conditional survival
• treatment
• surgery

Data Sharing Statement

Aggregated data from a publically accessible database were used. Full statistical R code is available at https://github.com/filip-tichanek/lungs.

Ethics

Anonymous data from a publically available database were used posing no ethical issues. The IARC website on NORDCAN describes under “About the project” that “Data in NORDCAN is freely available”; IARC is an intuition of the World Health Organization. The Finnish regional ethical committee instructions state that “[…] ethical approval is normally not required, as stipulated by the legislation, for example in simple interview research or research based on patient records and/or registers-based research, as long as the patients’ identity is not violated.” (translated from Finnish).

(Alueellinen lääketieteellinen tutkimuseettinen toimikunta - Pohjois-Savo (psshp.fi)).

Disclosure

AH is a shareholder in Targovax ASA. AH is an employee and shareholder in TILT Biotherapeutics Ltd. The other authors declared no conflict of interest.

Additional information

Funding

Supported by the European Union’s Horizon 2020 research and innovation programme, grant No 856620 (Chaperon), Jane and Aatos Erkko Foundation, Sigrid Juselius Foundation, Finnish Cancer Organizations, University of Helsinki, Helsinki University Central Hospital, Novo Nordisk Foundation, Päivikki and Sakari Sohlberg Foundation, Finnish Red Cross Blood Service, the Cooperation Program, research area SURG and National Institute for Cancer Research – NICR (Programme EXCELES, ID Project No. LX22NPO5102), funded by the European Union - Next Generation EU.