Abstract

Background

Despite having poor prognosis, survival from lung varies internationally. Here, we sought to assess the contribution of histological subtype, stage at diagnosis and sex in explaining international survival differences.

Method

Data on N=278,410 invasive non-small cell (NSLC) and small cell (SCLC) lung cancer cases (ICD-O-3 C34) diagnosed in 2010-2014 from 18 cancer registries in seven countries (Australia, Canada, Denmark, Ireland, New Zealand, Norway, and the United Kingdom) were obtained. Stage at diagnosis was mapped to one common stage system with three categories (localized, regional and distant), missing stage at diagnosis was imputed. One- and three-year age-standardized net survival was estimated by sex, histological type, stage and country.

Results

Overall, survival at 1-year after diagnosis was consistently higher in Canada and Norway, intermediate in Denmark and Australia and lowest in the UK, New Zealand and Ireland; irrespective of stage at diagnosis. In males, 3-year net survival ranged from 21.3% in the UK to 28.5% in Canada, while it was consistently higher in females (28.2% in the UK; 36.8% in Canada). International differences in survival from NSCLC were less pronounced at the advanced stage and largest for regional disease. For SCLC, 3-year net survival also showed a clear female advantage with highest values observed in Canada (13.8% in females; 9.1% in males) and Norway (12.8% in females; 9.7% in males).

Conclusion

Survival differences were most distinct for regional disease and NSCLC, suggesting potential linked to variation in diagnosis, quality of treatment, healthcare system (i.e. centralisation), and prevalence of comorbid conditions. Other possible explanations for the survival differences include differences in the approach to cancer registration, data collection as well as staging and cancer classification practice within jurisdictions.