Frequency of Colorectal Neoplasia in Young Onset Colorectal Cancer Does Not Warrant Shorter Surveillance Intervals

Introduction: The overall incidence of sporadic young-onset colorectal cancer (YO-CRC) is increasing and novel surveillance strategies have yet to be implemented. We sought to identify whether the outcomes of surveillance colonoscopies of patients with YO-CRC differ when compared to those with average onset colorectal cancer (AO-CRC) patients. If so, this will help inform the development of future surveillance guidelines for patients with YO-CRC. Methods: YO-CRC patients (aged 18-49), and randomly selected AO-CRC patients (aged >/=50) at Memorial Sloan Kettering Cancer Center with at least one recorded surveillance colonoscopy occurring between 01/01/2004 to 07/31/2017, were retrospectively reviewed excluding cases of Lynch syndrome, Inflammatory Bowel Disease, or an adenomatous polyposis syndrome. Results: 679 YO-CRC patients underwent 1,851 total surveillance colonoscopies, and 674 AO-CRC patients underwent 1,487 colonoscopies. Colorectal cancer was detected in 0.9% of YO-CRC patients and 1.2% of AO-CRC patients (RR: 1.34 95% CI: 0.47, 3.85) at 1st colonoscopy. Advanced neoplasia (defined as adenoma ≥ 1 cm, ≥ three adenomas, villous, tubulovillous, high grade dysplasia, or adenocarcinoma on pathology) was detected in 8.5% of the YO-CRC and 13.1% of the AO-CRC (RR: 1.53 95% CI: 1.12, 2.09) at 1st colonoscopy. Based on the cumulative risk over both the first and second surveillance intervals, 1.6% of YO-CRC, and 1.5% of AO-CRC developed colorectal cancer (RR: 1.41 95% CI 0.63, 3.15). ;12.1% for the YO-CRC and 22.6% of AO-CRC developed advanced neoplasia (RR: 2.23 95% CI: 1.31, 3.79). The average time interval from the initial surgery to the first colonoscopy date was 16.1 months for YO-CRC, and 15.7 for AO-CRC. The average interval for first colonoscopy to the second was 21.4 months for YO-CRC and 25.8 months for AO-CRC. Conclusion: The incidence of colorectal cancer in surveillance colonoscopies between AO and YO CRC were equivalent, but the frequency of advanced adenomas was significantly higher in AO-CRC. Changes to surveillance colonoscopy guidelines may not be warranted in YO-CRC.