Survival after resection for primary lung cancer

Nearly all that we believe in surgery and nearly all that we practise is based on observational data, usually in the form of collected series.¹ Lung cancer surgery is no exception, and we rely—and will continue to rely—on the analysis of observational data. Observational research has tended to be denigrated and neglected.² There is currently a lack of broad based data of sufficiently high quality,³ so we welcome the Norwegian population based study reported by Strand et al in this issue of Thorax.⁴

The Scandinavian nations have been a great resource of high quality observational data and, in the BMJ alone, we have seen many community based,⁵ population based,^6–8 and registry studies,⁸ of which those cited^5–8 are a tiny but representative sample of the many submitted. Indeed, UK groups have been attracted to these databases for their own studies.^5,9 Scandinavian society has a number of features that seem, to outsiders at least, to provide a fertile environment for such studies. They have well developed healthcare systems with uniformly high standards and equitable access. Also, the populations are relatively stable—for example, only 13 of 3211 (0.4%) operated patients in the Norwegian study were lost due to emigration. Importantly, collection and analysis of data to inform policy is accepted in these countries as a right and proper function of the state. Strand et al relied on a population based cancer registry with obligatory entry by law, with no need for the patient’s consent, and which is automatically linked to the Norwegian Central Bureau of Statistics.⁴

Before discussing the results presented by Strand et al …