Interval cancer - a breast cancer diagnosis between screening tests

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

Interval cancer is not common

Interval cancers happen in every screening programme. They are unavoidable. But interval cancers are not common.

Interval cancers occur in around 2 in every 1,000 women screened. This is a low rate that compares well internationally.

Infographic explaining the limitations of breast screening. Out of every 1,000 women screened for cancer, 7 will be diagnosed with cancer. 993 will receive a normal result, and of these women 2 will have an interval breast cancer.
Limitations of breast screening graphic.
An infographic explaining interval cancers. Of 100 women with breast cancer, when their mammograms are reviewed: 90 will have no sign of abnormality, 10 will have an abnormality in the mammogram which was missed due to a number of reasons.
Breast screening - interval cancers explained graphic.

Types of interval cancers

There are 3 types of interval cancer in breast screening.

  1. Newly detectable cancers that have developed since your last screening appointment.
  2. Cancers that were visible at the last screen but not recalled for further tests. This usually happens because the signs of cancer were very subtle and thought to be normal.
  3. Cancers that were visible at the last screen but not recalled for further tests. This usually happens because the signs were missed. This is rare.

Review your screening history after interval cancer diagnosis

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

We are updating our review process at the moment and will update this page with details when this process has been finalised.

Read an expert panel review of our interval cancer review process.

If you have any queries about interval cancers or the review process, you can contact your screening unit or you can contact:

Page last reviewed: 20 October 2020
Next review due: 20 October 2023