Table 3.
Change overtime in the intervals between the first and second and third colonoscopy during the study period.*
| Year of diagnosis | ||||||
|---|---|---|---|---|---|---|
| Percentile | 1992–1994 | 1995–1997 | 1998–2000 | 2001–2003 | Log rank P-value*** |
|
| Time between first and second colonoscopy (months) | Q1 | 14* | 15 (15 – 16) | 17 (16 – 18) | 19 (18 – 20) | <0.0001 |
| Q2 | 26 (25 – 27) | 28 (27 – 30) | 31 (29 – 32) | 32 (30 – 34) | ||
| Q3 | 58 (51 – 66) | 52 (48 – 57) | 53 (50 – 60) | |||
| Time between second and third colonoscopy (months) | Q1 | 15 (14 – 15) | 18 (17 – 20) | 23 (21 – 24) | 22 (19 – 23) | 0.0106 |
| Q2 | 31 (28 – 33) | 36 (34 – 37) | 36 (35 – 37) | 29 (28 – 32) | ||
| Q3 | 60 (55 – 63) | 60 (56 – 64) | 56 (50 – 61) | |||
*
The median and 25th and 75th percentiles for months between a first normal colonoscopy following surgery for colorectal cancer and any follow up colonoscopy are given.
**
Requiring weekly data to estimate 95% confidence interval, the rate of colonoscopy jumped from 21.9% at 13 months to 28.8% at 14 months.
***
The log rank test assesses the rate of colonoscopy at the entire follow-up period between patients diagnosed at different eras.