Potential number of colorectal cancers (CRCs) detected by flexible sigmoidoscopy (FS) (excluding those of unknown site and categorising multiple tumours as rectal as they are likely to be detected by FS)
| No CRC potentially detected by FS/site (total No CRC/site) | |||
| Site | % of FS viewing site | 1976–78 | 1990–97 |
| Proximal | 3.3 | 9.6 (292) | 62.4 (1890) |
| Distal | 74.4 | 252.2 (339) | 1040.1 (1398) |
| Rectal | 100 | 551.0 (551) | 1682.0 (1682) |
| Total | 812.9 (1182) | 2784.5 (4970) | |