Clinical features of post-colonoscopy colorectal cancer and real-world multi-scale correlation analysis

Post-colonoscopy colorectal cancer (PCCRC) remains an important issue in endoscopic examination. This study investigates the clinical features of PCCRC and possible correlation factors.

To explore clinical features of PCCRC and correlation factors.

A retrospective cohort analysis enrolled patients diagnosed with colorectal cancer (CRC) via colonoscopy at West China Hospital, Sichuan University, between January 1, 2022, and December 30, 2024. Demographic data, tumor characteristics, endoscopic findings, and miss records were extracted from electronic medical records and telephone follow-ups. An exploratory analysis was performed to identify causes of missed diagnosis during endoscopy.

Among 5411 colonoscopies in 2047 CRC patients, 66 prior examinations (27 colonoscopies in 17 non-PCCRC patients; 39 colonoscopies in 25 PCCRC patients) failed to establish diagnosis. The overall miss rate was 1.2%, with a PCCRC rate of 0.7%. Compared to the non-PCCRC group, advanced age was significantly associated with PCCRC (P = 0.006). The most common location that occurred PCCRC was sigmoid colon. PCCRC cases had higher rate of prior CRC surgery (41.0%). For endoscopists, PCCRC cases with CRC surgery increased the risk of judgement error. Insertion time demonstrated a positive correlation with missed diagnosis risk, whereas withdrawal time exhibited a negative correlation.

The incidence of PCCRC remains significant. Beyond tumor characteristics, endoscopist proficiency and procedural factors critically impact detection accuracy.