Overview of studies on interval CRCs after colonoscopy in asymptomatic populations, showing that variation in the definitions used for an interval CRC affects the estimated rates
| Studies | Definition iCRC | Design | Outcomes | Stage of CRC (I–II vs. III–IV) | Location of CRC (proximal vs. distal) | Risk factors/possible aetiology |
|---|---|---|---|---|---|---|
| Brenner et al (2012)24 Germany | 1–10 years after negative colonoscopy | Population-based; 1945 CRC cases; 2399 controls | 433 screen detected vs. 78 iCRCs | Screen detected: 282 vs. 149 iCRCs: 39 vs. 39 | Screen detected: 167 vs. 243 iCRC 44 vs. 32 | Predictors of iCRCs |
| Strock et al (2011)23 Luxembourg | All CRCs after index colonoscopy | Retrospective; 8950 patients after screening CS | 19 iCRCs in 47 725 person-years follow-up | Not specified | iCRC: 6 vs. 13 | N/A |
| Kaminski et al (2010)48 Poland | CRC diagnosed between screening and surveillance examination | Retrospective. 45 026 patients in colonoscopy screening programme | CRC incidence; 42 iCRCs in 188 788 person-years of follow-up | Not specified | iCRC: 12 vs. 25 | Association ADR of individual endoscopists |
| Matsuda et al (2009)22 Japan | <36 months | Observational, cohort study, NPS; 5309 patients | Incidence of advanced neoplasms after CS: 13 iCRCs within 3 years | iCRC: 12 vs. 1 | iCRC: 5 vs. 8 | Macroscopic appearance (5 depressed, 2 flat) |
| Kahi et al (2009)51 USA | Not defined | Retrospective. screening cohort of 715 patients vs. SEER data | 5 screen detected; 7 iCRCs in 10 492 person-years follow-up | Screen detected 5 vs. 0 iCRC: 4 vs. 3 | Screen detected 2 vs. 3 iCRC: 6 vs. 1 | N/A |
| Lieberman et al (2007)21 USA | <5 years after screening colonoscopy | Prospective. 3121 screenees | 1.7 per 1000 person years follow-up | iCRC: 10 vs. 4 | iCRC: 7 vs. 7 | N/A |
ADR, adenoma detection rate; CRC, colorectal cancer; CS, colonoscopy; iCRC, interval CRC; N/A, not applicable; NPS, National Polyp Study; SEER, Surveillance, Epidemiology and End Results.