Frequently asked questions
Stage at diagnosis
What is stage at diagnosis?
Stage at diagnosis, helps measure how early the cancer was diagnosed. In general, cancers start out at an early stage and then some progress over time to a higher stage. This progression involves the cancer growing and spreading.
Different staging categories are used for different types of cancer. Below is an example of one common method of staging.
- Stage 0 – indicates that the cancer has remained where it started (in situ) and hasn't spread. These cancers are not malignant so not included in the data for this website. For the numbers in breast and cervix please see the N. Ireland Cancer Registry website.
- Stage I – the cancer is small and hasn't spread anywhere else
- Stage II – the cancer has grown, but hasn't spread
- Stage III – the cancer is larger and may have spread to the surrounding tissues and/or the lymph nodes (part of the lymphatic system)
- Stage IV – the cancer has spread from where it started to at least one other body organ; also known as "secondary" or "metastatic" cancer
Where has the stage at diagnosis data come from?
The data has been sourced by Macmillan from the N. Ireland Cancer Registry (NICR) website. The NICR has calculated stage at diagnosis from their database of cancer patients in NI that includes stage at diagnosis for many patients.
N. Ireland Cancer Registry (NICR). Data extract. 2017.
How is the stage at diagnosis data used?
Survival charts show us that the earlier (lower stage) a cancer is diagnosed, the higher the survival rate. Therefore any actions that can lead to earlier diagnosis should help improve survival rates. The data presented helps identify cancers that are currently and frequently diagnosed at a late stage and the impact this late diagnosis has on survival.
What are age-standardised and unstandardised rates and why have they been used?
Age-standardised rates remove the impact of the variation in the age structures of populations. The age-standardised rates adjust for age to allow comparison between different areas or between different periods of time.
We present both age-standardised and unstandardised rates as in some cases the cancer population was too small to have enough cases in each age range to be able to calculate age standardised rates.