The incidence and clinical associated factors of interval colorectal cancers in Southern Taiwan.

BACKGROUND/PURPOSE: Interval colorectal cancer (CRC) is an emerging issue in CRC screening and surveillance. The frequency of interval CRC and its associated factors have not been well studied in Eastern Asia. We aim to clarify the factors associated with interval CRC.

METHODS

CRC patients who had negative colonoscopy results 6-36 months prior to cancer diagnosis were defined as cases of interval CRC. Patient characteristics, past history, colon preparation, colonoscopy findings, and pathology were retrospectively evaluated. A total of 670 patients with colorectal adenocarcinoma by pathology who also underwent colonoscopy before diagnosis from January 2005 to November 2014 were recruited.

RESULTS

Twenty-two (3.28%) patients (65.7 ± 9.2 years old; 9 male) were diagnosed with interval CRC. The interval CRCs were predominantly located at the rectum and cecum, and presented as earlier stage cancers (Stage I and Stage II: 86.4%, Stage III and Stage IV: 13.6%). Factors associated with interval cancer include end-stage renal disease (ESRD) (hazard ratio: 10.494, 95% confidence interval: 2.131-51.681) and shorter ascending colon withdrawal time (interval cancer: noninterval cancer 2.00±0.82: 4.91±3.74 minutes; hazard ratio: 0.561, 95% confidence interval: 0.345-0.913). Prior polypectomy and tumor size also tended to be related to interval CRC.

CONCLUSION

The prevalence of interval CRC in the present study is 3.28%. Comorbidity with ESRD and shorter ascending colon withdrawal time could be factors associated with interval CRC. Good colon preparation for the patients with ESRD and more ascending colon withdrawal time could reduce the interval CRC.