Beware interval cancers with FOBT

Interval cancers may occur in bowel cancer screening and therefore a negative FOBT test should not be taken as a sign that all is well, UK clinicians have warned.

Writing in the BMJ this week, British doctors say that up to a quarter of colorectal cancers identified in an audit occurred in patients who had a negative FOBT.

Their analysis was of data from a single area in the National Bowel Cancer Audit program where people between the ages of 60 and 70 have FOBT screening every two years.

In an area covering 22,000 people, 131