Letter Re: Survival trends in solid cancers in the Nordic countries through 50 years

One of the most recent articles using data from NORDCAN in the European Journal of Cancer is the article ‘Survival trends in solid cancers in the Nordic countries through 50 years’ by Janne Hemminki, Asta Försti, Akseli Hemminki and Kari Hemminki [ ]. In this article, the writers state that ‘The data used originate from the NORDCAN database …“, which is correct. The second paragraph of ‘Methods’ gives the details on how the survival analysis is performed. This paragraph, however, does not say anything about the fact that all survival analyses are already done by NORDCAN, in the NORDCAN pipeline and tool (nordcan.R), prior to being sent to the International Agency for Research on Cancer and the NORDCAN database [ ]. In our opinion, this paragraph in ‘Methods’ gives the impression that Hemminki et al. have done the survival analysis themselves, based on the raw data from the NORDCAN database. This is not correct. It is not possible to get access to raw data, which are sufficient to do survival analysis from the NORDCAN database, and all statistics on 1-year and 5-year survival used in this article are retrieved directly from the NORDCAN web tool, without the possibility (or need) to do additional analysis. The impression that the authors did the survival analysis themselves is also supported by the fact that all authors are stated as contributors to ‘Statistical analysis and interpretation’ under ‘Author contributions’ and the fact that they do not make a reference to NORDCAN and how the analyses are downloaded and used from there.