Colorectal screening programmes involve two tests: the detection of occult blood in faeces followed by colonoscopy if positive.
In Veneto, 23,400 people were studied who, after a positive test for occult blood, did not complete the course and refused colonoscopy. Compared to those who performed the endoscopic examination, their risk of death from colon cancer was found to be double.
At a national level, this problem affects more than 20% of the test positive for occult blood. In 2019, out of more than 137,000 people with a positive fecal test, only 106,000 performed colonoscopy.
Pubmed https://pubmed.ncbi.nlm.nih.gov/33789965/