Table 2.
Relative risks of incidence and mortality for each cancer type according to groups and the number needed to screen to prevent one event in the present follow-up period
| Characteristic | Invited to screening group (n=338 017) | Control group (n=299 483) | Screened versus control group | Invited to screening group versus control group | Number needed to screen (95% CI)‡ | ||||||
| Screened (n=113 340) | Not screened (n=224 677) | ||||||||||
| Cases | Rate (95% CI)* | Cases | Rate (95% CI)* | Cases | Rate (95% CI)* | Relative risk (95% CI)† | P value | Relative risk (95% CI)† | P value | ||
| Incidence | |||||||||||
| Upper gastrointestinal cancer¶ | 2201 | 327.54 (312.14 to 342.94) | 5596 | 394.48 (383.31 to 405.66) | 12 333 | 429.92 (421.97 to 437.86) | 0.77 (0.74 to 0.81) | <0.001 | 0.86 (0.84 to 0.89) | <0.001 | 98 (85 to 115) |
| Oesophageal cancer | 1127 | 160.60 (150.09 to 171.11) | 2896 | 202.60 (194.55 to 210.66) | 6305 | 219.98 (214.28 to 225.69) | 0.74 (0.69 to 0.79) | <0.001 | 0.85 (0.82 to 0.89) | <0.001 | 168 (143 to 206) |
| Non-cardia gastric cancer | 443 | 68.51 (61.23 to 75.79) | 1426 | 100.61 (94.99 to 106.23) | 3107 | 103.89 (100.09 to 107.69) | 0.66 (0.59 to 0.73) | <0.001 | 0.88 (0.83 to 0.94) | <0.001 | 283 (235 to 359) |
| Cardia gastric cancer | 634 | 96.29 (87.86 to 104.72) | 1277 | 88.48 (83.33 to 93.63) | 2928 | 100.39 (96.59 to 104.19) | 0.99 (0.90 to 1.09) | 0.213 | 0.90 (0.84 to 0.96) | 0.008 | NA§ |
| All-site cancer | 3899 | 572.95 (552.76 to 593.15) | 10 302 | 757.34 (741.36 to 773.31) | 22 051 | 777.46 (766.7 to 788.23) | 0.75 (0.73 to 0.78) | <0.001 | 0.89 (0.86 to 0.91) | <0.001 | 49 (45 to 54) |
| Mortality | |||||||||||
| Upper gastrointestinal cancer | 733 | 108.98 (99.99 to 117.96) | 2893 | 199.10 (191.21 to 206.99) | 6386 | 238.22 (232.06 to 244.38) | 0.43 (0.40 to 0.47) | <0.001 | 0.69 (0.66 to 0.72) | <0.001 | 77 (72 to 84) |
| Oesophageal cancer | 372 | 52.69 (46.64 to 58.74) | 1485 | 101.76 (96.10 to 107.42) | 3317 | 125.07 (120.57 to 129.58) | 0.40 (0.36 to 0.45) | <0.001 | 0.67 (0.63 to 0.71) | <0.001 | 138 (127 to 153) |
| Non-cardia gastric cancer | 175 | 27.50 (22.79 to 32.21) | 833 | 58.34 (54.03 to 62.65) | 1853 | 66.66 (63.49 to 69.83) | 0.38 (0.33 to 0.45) | <0.001 | 0.72 (0.66 to 0.78) | <0.001 | 255 (227 to 295) |
| Cardia gastric cancer | 186 | 28.79 (24.11 to 33.46) | 575 | 39.00 (35.60 to 42.40) | 1216 | 46.48 (43.73 to 49.23) | 0.58 (0.49 to 0.68) | <0.001 | 0.72 (0.65 to 0.80) | <0.001 | 565 (447 to 795) |
| All-site cancer | 1475 | 217.46 (204.85 to 230.06) | 5340 | 381.57 (370.37 to 392.78) | 11 786 | 433.91 (425.64 to 442.19) | 0.48 (0.45 to 0.50) | <0.001 | 0.72 (0.70 to 0.75) | <0.001 | 46 (44 to 49) |
| All cause | 3705 | 565.21 (547.30 to 583.70) | 13 713 | 1001.79 (985.16 to 1018.70) | 27 646 | 970.23 (958.86 to 981.74) | 0.49 (0.47 to 0.51) | <0.001 | 0.75 (0.74 to 0.77) | <0.001 | 25 (23 to 26) |
*Rates are per 100 000 person-years and standardised by age, sex and centre.
†Relative risks are standardised by age, sex and centre.
‡Number needed to screen to prevent one event in the control group.
§Not available.
¶Thirteen patients had both a oesophageal cancer and gastric cancer.