Comparison of survival following colorectal cancer in England, Northern Ireland, Scotland and the Nordic countries using period survival methods Gerda Engholm Danish Cancer Society

Project group Project: Pilot study on period survival following colorectal cancer in UK and the Nordic countries Gerda Engholm, Anne Mette Kejs, Hans Storm Danish Cancer Society Henrik Møller, Thames Cancer Registry David Brewster, Scottish Cancer Registry Risto Sankila, Finnish Cancer Registry On behalf of the collaborating registries

Cancer distribution in % in the Nordic countries in MenProstateColorectalLung Incidence Deaths WomenBreastColorectalLung Incidence29137 Deaths1713

Purpose of study The work with cancer plans in England, Scotland, Norway, and Denmark call for a more timely estimate of todays survival than possible with the usual cohort survival methods, where 5-year survival for patients diagnosed a specific year cannot be calculated before at least 5 years following the year of diagnosis has passed The period survival makes it possible to calculate cross- sectional survival probabilities in a more timely fashion and makes it possible to detect an improvement in cancer treatment earlier than with traditional cohort methods To interpret the differences we want also to compare incidence, mortality, stage distribution and conditional survival probabilities with each year of follow up

Definitions and restrictions Diagnoses as in NORDCAN –Colon cancer: C18 in ICD10 –Rectum cancer : C19-C21 First cancer, excluding non-melanoma skin Ages 0-89 at diagnosis, 0-44,45-64,65-74, Age-standardized relative survival, 0-5 years Period survival with 2-year window of follow-up , using cancer cases diagnosed

Conclusions The 5 year relative survival following colorectal cancer is lowest in Denmark, followed by UK, and highest in Sweden Variations in annual relative survival are bigger for the first year compared to year 2, 3, 4, and 5 Analysis with excess risk modelling should be made separately for the first year Models should include or stratify by extent of disease –keeping in mind that registration of extent differ between countries, ie Finland has a different pattern than the other countries