Background: The primary benefit of post-colorectal cancer (CRC) colonoscopic surveillance is to detect and remove premalignant lesions to prevent metachronous CRC. Current guidelines for long-term colonoscopic surveillance post early-age onset CRC (EOCRC) resection are based on limited evidence. The aims of this study were to assess the diagnostic yield of colonoscopic surveillance post-EOCRC resection and identify molecular and clinicopathological risk factors associated with advanced neoplasia.
Methodology: A retrospective cohort study of prospectively collected data was conducted at St Mark’s Hospital, London, United Kingdom, for patients diagnosed with EOCRC that underwent at least one episode of post-CRC colonoscopic surveillance between 1978 and 2022. We collected clinicopathological data including tumour molecular status and neoplasia detection rates.
Results: In total, 908 colonoscopic surveillance procedures were performed in 195 patients over 2581.3 person-years of follow-up. The diagnostic yield of metachronous CRC, advanced adenomas and non-advanced adenomas were 1.76%, 3.41% and 22.69% respectively. Sixteen patients (8.21%) developed metachronous CRC, and the majority (87.5%) were detected more than 3 years post index EOCRC diagnosis. Detection of advanced neoplasia was significantly higher in EOCRC patients with Lynch syndrome (26.15%) compared to where Lynch syndrome was excluded (13.13%) (OR, 2.343; 95% CI, 1.014 to 5.256; P=0.0349).
Conclusions: During colonoscopic surveillance post-EOCRC resection, the long-term risk of developing metachronous advanced neoplasia remains high in the context of Lynch syndrome but this trend is not as clearly evident when Lynch syndrome has been excluded.