Danish multidisciplinary cancer groups – DMCG.dk benchmarking consortium: Article series on cancer survival and mortality in Denmark 1995–2012

This article is part of a series including:

Improvements in breast cancer survival between 1995 and 2012 in Denmark: The importance of earlier diagnosis and adjuvant treatment

Improved survival of colorectal cancer in Denmark during 2001–2012 – The efforts of several national initiatives

Survival of ovarian cancer patients in Denmark: Results from the Danish gynaecological cancer group (DGCG) database, 1995–2012

Mortality and survival of lung cancer in Denmark: Results from the Danish Lung Cancer Group 2000–2012

In response to the literature, that Denmark ranks low in international comparisons of cancer survival, the Danish Multidisciplinary Cancer Groups (DMCG.dk) Benchmarking Consortium set out to investigate cancer survival and mortality in Denmark based on prospective clinical data on breast, lung, colorectal and ovarian cancers. The resulting article series provides novel insight on temporal trends and developments in cancer survival in Denmark for the period 1995–2012, with data based primarily on national clinical databases for quality improvement and research [1–4].

Measuring cancer survival and mortality within a country, let alone in comparison to neighboring countries, is a complex and challenging endeavor, but nevertheless important. The results presented in this article series are based on hospital-based data, linked to central registries, in contrast to survival estimates from other multinational collaborations, where data are often taken from population-based registries (i.e. national cancer registries). Prospective clinical data from the national DMCG.dk cancer clinical databases were used to compute age-standardized one- and five-year mortality rates, survival proportions, and relative survival for four major cancer diseases.

This series highlights some of the pitfalls and challenges of comparing cancer mortality within and between countries. The four cancer-specific papers in this article series [1–4] provide robust evidence that cancer survival in Denmark has consistently improved over the past 20 years, and that Danish cancer survival, especially in the most recent years, is higher than what has been previously reported elsewhere. The key lesson from this series is that data correctness (e.g. completeness, validity) and robust methodology is paramount, as is comparing ‘apples with apples’ and ‘oranges with oranges’ when conducting benchmarking comparisons.

On behalf of the DMCG.dk Benchmarking Consortium,

Mary Nguyen Nielsen, MD, Academic Secretary for DMCG.dk

Michael Borre, MD, PhD, dr.med., Chair of DMCG.dk and Professor of Urology