Table 2. Numbers of CRC Cases and CRC Deaths Prevented After Sigmoidoscopy or Colonoscopy Screening Compared With Usual Care in Intention-to-Treat Analysesa.
| CRC | Compared with usual care | Colonoscopy screening compared with sigmoidoscopy | ||||
|---|---|---|---|---|---|---|
| As observed in sigmoidoscopy trials | As estimated for colonoscopy | |||||
| No. of events prevented (95% CI) | NNS (95% CI)b | No. of events prevented (95% CI) | NNS (95% CI)b | Additional No. of events prevented (95% CI) | Numbers needed to switch (95% CI)b | |
| Incidence | ||||||
| All individuals | 37 (30-44) | 188 (158-231) | 50 (42-58) | 139 (118-164) | 12 (10-14) | 560 (486-661) |
| Women | 20 (11-28) | 352 (243-638) | 31 (21-42) | 218 (161-336) | 11 (8-14) | 610 (474-853) |
| Men | 56 (46-67) | 126 (106-155) | 70 (59-82) | 100 (85-120) | 13 (10-15) | 541 (458-661) |
| Mortality | ||||||
| All individuals | 11 (7-14) | 598 (450-888) | 15 (11-19) | 415 (327-567) | 4 (3-5) | 1611 (1275-2188) |
| Women | 4 (0-9) | 1478 (733-infinity) | 8 (2-13) | 807 (478-2572) | 3 (1-4) | 2248 (1376-6140) |
| Men | 18 (12-23) | 367 (280-533) | 23 (17-29) | 281 (222-383) | 5 (4-6) | 1300 (1017-1798) |
Abbreviations: CRC, colorectal cancer; NNS, number needed to invite to screening.
a
Numbers are presented per 100 000 person-years; the number of additional events prevented is not exactly the difference of colonoscopy effectiveness minus sigmoidoscopy effectiveness because the trial weights were slightly different.
b
Number of individuals who need to switch screening method (from sigmoidoscopy to colonoscopy) to prevent 1 additional event.