Overview of studies on interval CRCs after colonoscopy in a mix of symptomatic and asymptomatic populations, showing that variation in the definitions used for an interval CRC influences 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 |
|---|---|---|---|---|---|---|
| Corley et al (2014)49 USA | 6 months-10 years after colonoscopy | Retrospective, population-based, 314 872 colonoscopies 712 patients with iCRC | 712 iCRC in 927 523 person-years follow-up; 8.2% of all CRCs were iCRCs | iCRCs: 457 vs. 255 | iCRC: 427 vs. 267 (18 unknown) | Inverse association between ADR and risk of iCRC, advanced iCRC and fatal iCRC |
| Erichsen et al (2013)42 Denmark | 1–5 years | Retrospective, 982 patients with iCRC vs. 358 patients with colonoscopy >10 years vs. 35 704 patients with sporadic CRCs | 982/38 064=2.6% iCRCs | Sporadic CRC: 12 995 vs. 17 982 iCRC: 377 vs. 414 | Sporadic CRC: 9782 vs. 23 979 iCRC: 441 vs. 433 | Predictors of iCRCs |
| le Clercq et al (2013)39 The Netherlands | <5 years | Retrospective, population-based, 5107 patients with CRC | 147/5107=2.9% iCRCs | Sporadic CRC: 2499 vs. 2531 iCRC: 79 vs. 63 | Sporadic CRC: 1634 vs. 3522 iCRC: 87 vs. 59 | Predictors of iCRCs |
| Cooper et al (2012)36 USA | 6–36 months | Retrospective. SEER-Medicare database with 57 839 CRC patients | 7.2% had prior colo 53.647 detected CRC 4192 iCRCs | Screen detected: 29 172 vs. 18 778 iCRCs: 2444 vs. 1291 | Screen detected: 25 870 vs. 17 921 iCRC: 2851 vs. 819 | N/A |
| Huang et al (2012)38 China | <5 years | 1764 patients with adenomas under surveillance | 14/1794 iCRCs=0.78% =2.9 cases per 1000 person-years follow-up | iCRCs: 9 vs. 4 | iCRC: 11 vs. 3 | Possible aetiology |
| Horiuchi et al (2011)40 Japan | <5 years after negative colo | Prospective cohort of 3212 patients with negative CS | 9 iCRCs within 5 years | iCRC: 7 vs. 2 | iCRC: 6 vs. 3 | N/A |
| Baxter et al (2011)19 Canada | 7–36 months | Observational study of 14 064 CRC patients | Incidence iCRC: 9.0% of all diagnosed CRCs | Not specified | iCRC: 676 vs. 584 | N/A |
| Leung et al (2010)54 USA | Average 41 months; range 11–83 months | Prospective. Continued follow-up study (PPT) | 9 CRCs over 7626 person-years observation (1.2/1000) | iCRC: 7 vs. 2 | iCRC: 8 vs. 1 | Risk factors and possible aetiology |
| Ferrández et al (2010)52 Spain | <36 months | Retrospective. 16.866 colonoscopy reports | 386 CRC patients of whom 27 (7.0%) had prior CS | Not specified | iCRC: 6 vs. 21 | N/A |
| Singh et al (2010)18 Canada | 6–36 months | Population based study of 4883 CRC patients | Incidence iCRC: 7.9% (n=388) | iCRC 70 vs. 67 | iCRC: 225 vs. 147 | Risk factors |
| Lakoff et al (2008)47 Canada | >6 months | 110 402 patients with negative colonoscopy; 14 year follow-up Control: general population | 1.3% (n=1461) of cohort-patients develop CRC vs. 2.2% of controls | Not specified | Controls: 19 056 vs 33 195 iCRC: 610 vs. 443 | N/A |
| Imperiale et al (2008)68 USA | <5 years | 2436 with negative CS, 5-year follow-up | No iCRCs diagnosed | N/A | N/A | N/A |
| Bressler et al (2007)17 Canada | 6–36 months | Retrospective. Claims-based administrative data; 31 074 CRC patients | 12 487 had prior colo Detected: 12 057 New/missed: 3.4% (n=430) | Not specified | Detected: 3827 vs. 8422 New/missed: 238 vs. 192 | Risk factors |
| Farrar et al (2006)37 USA | <5 years | Retrospective. 830 CRC patients; 45 iCRCs vs. 90 sporadic CRCs | iCRC incidence: 5.4% of all diagnosed CRCs | Sporadic: 52 vs. 38 iCRC: 30 vs. 15 | Sporadic: 26 vs. 64 iCRC: 23 vs. 22 | Possible aetiology |
| Pabby et al (2005)44 USA | CRC detected during surveillance at year 1 or year 4 | Prospective; 2079 patients with 5810 person-years of observation (PPT) | 13 iCRC cases (2.2/1000 person-years observation) | iCRC: 8 vs. 5 | iCRC: 7 vs. 6 | Possible aetiology |
| Robertson et al (2005)53 USA | Any cancer diagnosed after a clearing colonoscopy | Prospective; 2915 patients, mean follow-up: 3.7 years (3 chemoprevention trials) | 19 CRCs in 2915; 1.74/1000 | iCRC 16 vs. 3 | iCRC 10 vs. 9 | Possible aetiology |
| Leaper et al (2004)50 New Zealand | >6 weeks | Retrospective; patients undergoing CS | 17 of 286 (5.9%) were missed by CS | iCRC: 10 vs. 7 | iCRC 13 vs. 4 | Possible aetiology |
ADR, adenoma detection rate; CRC, colorectal cancer; CS, colonoscopy; iCRC, interval CRC; PPT, Polyp Prevention Trial; N/A, not applicable.