[How many patients had their colon investigated within five years prior to colorectal cancer diagnosis?]

We aimed to investigate the prevalence of patients who had their colon investigated five years to three months before their colorectal cancer (CRC) was diagnosed. All patients diagnosed between January 1st 2016 and September 14th 2017 in the county of Västerbotten, Sweden were included (n=307). The proportion of patients with CRC who had their colon investigated before diagnosis was 7% (n=22). The median time from the index examination to the date of diagnosis of CRC was 1013 days (IQR 639 days). In addition, 16% of the patients had a positive FIT test (F-Hb) and 23% had anemia that was known more than three months prior to diagnosis. A long duration of anemia before diagnosis was significantly more common in men than in women (31% vs 16%; p=0.003). We conclude that the incidence of "missed" CRC are low but may be improved by a thorough adherence to colonoscopy guidelines. We found that a positive iFOBT and anemia often were detected more than three months prior to diagnosis.