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Frequently Asked Questions

What is a net survival rate?

Survival is an indicator of the percentage of people who are still alive a certain point after diagnosis.  For example, a 20% survival at one year means that 20% of the people live one year or more after their cancer diagnosis. The survival rates presented in this LCI NI tool have an additional adjustment to remove the impact of cancer patients who would have died anyway even without their cancer diagnosis - this is called net survival. 

Net survival is an estimate of survival where the effect on survival of background population mortality rates has been removed. It represents the [theoretical] survival of cancer patients if they could only die from cancer-related causes. Net survival is suitable for comparison of survival between different time periods and populations, as the confounding effect of non-cancer death rates is removed.

Presented here are 6 month, 1-year and 5-year net survival rates. 

Overall survival rates by age group are based on people diagnosed between 2003 and 2010. Survival trends over time (by sex and cancer type) are based on different diagnosis periods (1993-1999, 2000-2004, 2005-2009 and 2010-2014).

Where are the cancer survival data from?

The data has been sourced by Macmillan from the N. Ireland Cancer Registry (NICR).  The NICR has calculated survival based on their database of cancer patients in NI and life tables of the general NI population.

N. Ireland Cancer Registry (NICR). Data extract. 2017.

Why is the period of diagnosis used in the analysis so long?

In order to create a robust survival rate, there needs to be sufficient patients surviving up to five years post diagnosis.  This means for smaller sub-national areas and rarer cancers, the period of diagnosis needs to be extended. 

Survival rates increase over time so in order to create fair comparisons between cancers and geographies the years must be consistent across groups.

Why is survival data not provided by council area?

This data is currently being reviewed and we intend to represent it on the website in the near future.