Colorectal cancer is one of the most important causes of cancer morbidity and mortality worldwide. We have explored international variation in colorectal cancer survival, by topography and disease extension.
We analysed data on 4,877,818 individual malignant tumours of the colon or rectum diagnosed during 1995-2009, provided by 228 population-based cancer registries in 55 countries participating in the CONCORD programme for global surveillance of cancer survival. We defined four anatomic sub-sites: right colon, left colon, other/unspecified colon, and rectum. Data on stage at diagnosis were available for 655,844 patients diagnosed during 2001-2009, from 63 cancer registries in 21 countries. We only included registries with stage data available for 70% or more of patients. We estimated age-standardised net survival at five years after diagnosis, by country, topography and stage.
During 2004-2009, 5-year net survival ranged from 29 to 70% for patients with colon cancer, and from 32 to 74% for rectal cancer. In most countries, survival was comparable between tumours in the right colon (40-69%) and the left colon (33-71%), but tended to be lower for tumours of unspecified/other topography (18-63%). Five-year survival for localised colorectal cancer (38-94%) was considerably higher than for advanced disease (22-75%).
Five-year survival from colorectal cancer varies widely between countries, but also by sub-site and stage. These results offer the widest picture on the availability of data on stage at diagnosis and stage-specific cancer survival worldwide. Complete and standardised registration of stage at diagnosis is essential for valid population-based monitoring and international comparisons of cancer survival.
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London School of Hygiene and Tropical Medicine.
Canadian Partnership Against Cancer (Toronto, Canada), Cancer Focus Northern Ireland (Belfast, UK), Cancer Institute New South Wales (Sydney, Australia), Cancer Research UK (London, UK), Centers for Disease Control and Prevention (Atlanta, GA, USA), Swiss Re (London, UK), Swiss Cancer Research foundation (Bern, Switzerland), Swiss Cancer League (Bern, Switzerland), and University of Kentucky (Lexington, KY, USA).
All authors have declared no conflicts of interest.