Interval cancer - bowel cancer diagnosis in between screening tests

You can get cancer at any time, including between your screening tests. Cancers that are found in between screening tests are called 'interval cancers'.

Interval cancer is not common

Interval cancers happen in every screening programme. They are unavoidable.

But interval cancers are not common. For every 1,000 people screened in Ireland, around 2 of these will have interval cancer. This is a low rate that compares well internationally.

Why interval bowel cancer happens

An interval bowel cancer is a cancer that is diagnosed within 3 years of having a colonoscopy.

In most of these cases, there was no sign of cancer seen during the colonoscopy. In some interval cancers, some signs of cancer were there but were not found when the colonoscopy was done.

Review your screening history after interval cancer diagnosis

Anyone diagnosed with bowel cancer can request a review of their screening history.

We are putting in place a new review process.

We will update this page with details of how to request a review when this process has been finalised.

Download a review of our interval cancer review process (PDF, 1.5 MB, 78 pages)

If you have symptoms - phone your GP

Contact your GP without delay if you have any symptoms of bowel cancer.

This includes rectal bleeding or change in bowel habit.

Never ignore symptoms - even if you have had a recent normal screening result.

If you have any queries about interval cancer, contact us:

Page last reviewed: 20 October 2022
Next review due: 20 October 2025