Yield of advanced adenoma (AA) at surveillance endoscopy according to number of adenomas at index colonoscopy and timing of surveillance according to the guidelines (n=1904)
| Period of index colonoscopy | Recommended interval (year) | AA (n/n total) | |||
|---|---|---|---|---|---|
| Too early | Appropriate† | Delayed | Total | ||
| June 1998–2001 | |||||
| 1 adenoma | 2–3 | 3% (12/389) | 3% (13/384) | 7% (21/298)* | 4% (46/1071) |
| 2 adenomas | 1 | 6% (1/16) | 3% (3/90) | 6% (10/159) | 5% (14/265) |
| 3+ adenomas | 1 | 7% (1/14) | 9% (6/68) | 17% (15/89) | 13% (22/171) |
| Overall | 3% (14/419) | 4% (22/542) | 8% (46/546)** | 5% (82/1507) | |
| In 2002 | |||||
| 1 adenoma | 6 | 5% (9/193) | 7% (2/28) | 0% (0/3) | 5% (11/224) |
| 2 adenomas | 6 | 9% (8/86) | 8% (1/12) | – | 9% (9/98) |
| 3+ adenomas | 3 | 16% (7/44) | 0% (0/20) | 9% (1/11) | 11% (8/75) |
| Overall | 7% (24/323) | 5% (3/60) | 7% (1/14) | 7% (28/397) | |
| Total | 5% (38/742) | 4% (25/602) | 8% (47/560)** | 6% (110/1904) | |
AA includes adenomas with size of 10 mm or larger at pathology or endoscopy, villous histology or high-grade dysplasia, including CRC.
In total 14 CRCs were found at first surveillance colonoscopy (Before 2002: 1 CRC in those with too early surveillance, 1 CRC in those with appropriately timed surveillance and 10 CRCs in those with delayed surveillance. In 2002: 2 CRCs in those with too early surveillance).
*Significant at level p<0.05; **Significant at level p<0.01.
†Appropriate interval, before 2002: 1 year ±3 months, 2–3 years ±6 months; and in 2002: 3 years or 6-years ±6 months.
CRC, colorectal cancer.