EVALUATION OF CHARACTERISTICS AND INCIDENCE OF INTERVAL COLORECTAL CANCER

Aims:

The development of a colorectal cancer (CRC) after an initial exam before the established revision can be due to non-visualized lesions or the appearance of a new tumour and this is called interval colorectal cancer. Our aim was to know the incidence of colorectal cancer in our health area and the associated risk factors.

Methods:

We recovered all the CRC diagnosed in 2012 – 2013. Then we reviewed if the patient got a colonoscopy prior to the diagnosis and its findings. We considered two groups: the first, the ones who had a colonoscopy in the 5 years prior to the diagnosis and the other one included 10 years.

Results:

We found a total of 751 cases of CRC. In 86%, the indication for colonoscopy was symptoms, especially rectal bleeding and anaemia (28.8 and 20.1%). We detected a total of 16 cases that had a previous colonoscopy in the last 5 years and a total of 31 in the last 10 years, which represents an incidence of interval colorectal cancer of 2.31% and 4.13%. The majority had 1 or 2 previous endoscopies, with previous pathologic findings in 63.3%. In both groups, the median age of diagnosis was superior in the interval CRC group compared to general CRC (76.45 vs. 61.89 years in the 10 year group; p < 0.05). In the 10 year group, the most prevalent location was proximal while it was distal in the control group (54.84 vs. 59.81%; p = NS). The extension was local in 66.7% of cases at 5 and 10 years; on the other hand the local affection in the control group was 52.1% (p = 0.1).

Conclusions:

There are a percentage of cases of interval CRC that might be associated to low quality diagnostic and therapeutic endoscopic procedures. The endoscopy units must extreme measures for the correct visualization and extirpation of precancerous lesions.