Table 2.
Cumulative incidence of colorectal cancer and age-sex-standardised incidence ratios in the whole cohort (n=21 318)
| n | % | No of person-years | No of CRCs | Incidence rate per 100 000 person-years (95% CI) | At 10 years | P value† | Standardisation | |||
| No of CRCs | Cumulative incidence (95% CI)* | No of expected CRCs‡ | SIR (95% CI) | |||||||
| After baseline (without surveillance, censored at any first surveillance visit) | ||||||||||
| Total | 21 318 | 100 | 116 248 | 214 | 184 (161 to 210) | 183 | 1.9% (1.7 to 2.3) | 242 | 0.88 (0.77 to 1.01) | |
| Sex | 0.50 | |||||||||
| Women | 9022 | 42 | 52 431 | 93 | 177 (145 to 217) | 74 | 1.7% (1.3 to 2.2) | 87 | 1.08 (0.87 to 1.32) | |
| Men | 12 296 | 58 | 63 816 | 121 | 190 (159 to 227) | 109 | 2.1% (1.7 to 2.6) | 156 | 0.78 (0.64 to 0.93) | |
| Age at baseline, years | <0.001 | |||||||||
| <55 | 4298 | 20 | 26 718 | 12 | 45 (26 to 79) | 9 | 0.4% (0.2 to 0.8) | 13 | 0.93 (0.48 to 1.63) | |
| 55–64 | 5956 | 28 | 32 358 | 36 | 111 (80 to 154) | 30 | 1.3% (0.9 to 2.0) | 51 | 0.71 (0.50 to 0.98) | |
| 65–74 | 6894 | 32 | 35 831 | 94 | 262 (214 to 321) | 81 | 2.6% (2.1 to 3.3) | 100 | 0.94 (0.76 to 1.15) | |
| ≥75 | 4170 | 20 | 21 341 | 72 | 337 (268 to 425) | 63 | 3.6% (2.7 to 4.7) | 79 | 0.92 (0.72 to 1.15) | |
| No of PMPs | <0.001 | |||||||||
| 1 | 12 231 | 57 | 72 860 | 102 | 140 (115 to 170) | 82 | 1.4% (1.1 to 1.8) | 144 | 0.71 (0.58 to 0.86) | |
| 2 | 4714 | 22 | 24 974 | 59 | 236 (183 to 305) | 51 | 2.4% (1.8 to 3.2) | 56 | 1.06 (0.81 to 1.37) | |
| 3 | 2035 | 10 | 9612 | 22 | 229 (151 to 348) | 20 | 2.9% (1.8 to 4.6) | 22 | 1.00 (0.62 to 1.51) | |
| 4 | 951 | 4 | 3971 | 14 | 353 (209 to 595) | 14 | 5.4% (3.0 to 9.7) | 9 | 1.55 (0.84 to 2.59) | |
| ≥5 | 1387 | 7 | 4830 | 17 | 352 (219 to 566) | 16 | 3.7% (2.0 to 6.5) | 11 | 1.56 (0.91 to 2.49) | |
| PMP size, mm§ | 0.001 | |||||||||
| <10 | 11 553 | 54 | 72 061 | 112 | 155 (129 to 187) | 95 | 1.6% (1.3 to 2.0) | 145 | 0.77 (0.64 to 0.93) | |
| 10–19 | 6081 | 29 | 29 408 | 62 | 211 (164 to 270) | 52 | 2.2% (1.6 to 3.1) | 64 | 0.97 (0.75 to 1.25) | |
| ≥20 | 3625 | 17 | 14 553 | 39 | 268 (196 to 367) | 35 | 3.0% (2.0 to 4.4) | 33 | 1.18 (0.84 to 1.61) | |
| Adenoma histology¶ | 0.002 | |||||||||
| Tubular | 12 786 | 60 | 75 483 | 117 | 155 (129 to 186) | 100 | 1.6% (1.3 to 2.0) | 153 | 0.77 (0.63 to 0.92) | |
| Tubulovillous | 6480 | 30 | 30 698 | 68 | 222 (175 to 281) | 58 | 2.4% (1.8 to 3.2) | 68 | 1.00 (0.78 to 1.27) | |
| Villous | 1045 | 5 | 4505 | 14 | 311 (184 to 525) | 13 | 3.2% (1.7 to 5.9) | 11 | 1.29 (0.70 to 2.16) | |
| Unknown | 1007 | 5 | 5562 | 15 | 270 (163 to 447) | 12 | 3.1% (1.7 to 5.8) | 10 | 1.45 (0.81 to 2.40) | |
| Adenoma dysplasia** | <0.001 | |||||||||
| Low grade | 18 592 | 87 | 104 400 | 173 | 166 (143 to 192) | 145 | 1.7% (1.4 to 2.0) | 215 | 0.80 (0.69 to 0.93) | |
| High grade | 2148 | 10 | 8373 | 35 | 418 (300 to 582) | 33 | 5.2% (3.6 to 7.7) | 20 | 1.74 (1.21 to 2.42) | |
| Unknown | 578 | 3 | 3475 | 6 | 173 (78 to 384) | 5 | 2.2% (0.8 to 5.8) | 7 | 0.87 (0.32 to 1.89) | |
| Proximal polyps†† | <0.001 | |||||||||
| No | 11 566 | 54 | 67 073 | 88 | 131 (106 to 162) | 77 | 1.5% (1.2 to 1.9) | 133 | 0.66 (0.53 to 0.82) | |
| Yes | 9752 | 46 | 49 174 | 126 | 256 (215 to 305) | 106 | 2.5% (2.0 to 3.1) | 110 | 1.15 (0.96 to 1.37) | |
| No of APMPs and PMPs | <0.001 | |||||||||
| No APMPs, 1 PMP | 7506 | 35 | 49 423 | 66 | 134 (105 to 170) | 53 | 1.3% (1.0 to 1.8) | 96 | 0.69 (0.53 to 0.88) | |
| No APMPs, 2–4 PMPs | 3346 | 16 | 19 581 | 38 | 194 (141 to 267) | 34 | 2.2% (1.6 to 3.2) | 43 | 0.89 (0.63 to 1.22) | |
| No APMPs, ≥5 PMPs | 461 | 2 | 1991 | 3 | 151 (49 to 467) | 3 | 1.4% (0.4 to 4.5) | 4 | 0.73 (0.15 to 2.14) | |
| 1 APMP, no other PMPs | 4725 | 22 | 23 437 | 36 | 154 (111 to 213) | 29 | 1.6% (1.1 to 2.4) | 49 | 0.74 (0.52 to 1.02) | |
| ≥1 APMP, ≥2 total PMPs | 5280 | 25 | 21 815 | 71 | 325 (258 to 411) | 64 | 3.6% (2.7 to 4.8) | 51 | 1.39 (1.09 to 1.75) | |
| After first surveillance (with one or more surveillance visits, censored at end of follow-up) | ||||||||||
| Total | 11 604 | 100 | 94 567 | 154 | 163 (139 to 191) | 122 | 1.6% (1.4 to 2.0) | 213 | 0.72 (0.61 to 0.85) | |
| Sex | 0.66 | |||||||||
| Women | 4804 | 41 | 39 742 | 68 | 171 (135 to 217) | 56 | 1.9% (1.4 to 2.5) | 67 | 1.02 (0.79 to 1.29) | |
| Men | 6800 | 59 | 54 825 | 86 | 157 (127 to 194) | 66 | 1.5% (1.1 to 1.9) | 146 | 0.59 (0.47 to 0.73) | |
| Age at baseline, years | <0.001 | |||||||||
| <55 | 2702 | 23 | 24 746 | 24 | 97 (65 to 145) | 19 | 0.9% (0.6 to 1.4) | 19 | 1.25 (0.80 to 1.86) | |
| 55–64 | 3799 | 33 | 32 580 | 41 | 126 (93 to 171) | 30 | 1.2% (0.8 to 1.8) | 69 | 0.60 (0.43 to 0.81) | |
| 65–74 | 3780 | 33 | 29 354 | 64 | 218 (171 to 279) | 51 | 2.3% (1.7 to 3.1) | 95 | 0.68 (0.52 to 0.86) | |
| ≥75 | 1323 | 11 | 7887 | 25 | 317 (214 to 469) | 22 | 3.7% (2.3 to 6.0) | 30 | 0.83 (0.53 to 1.22) | |
| No of PMPs | <0.001 | |||||||||
| 1 | 6188 | 53 | 51 257 | 61 | 119 (93 to 153) | 51 | 1.3% (1.0 to 1.7) | 108 | 0.57 (0.43 to 0.73) | |
| 2 | 2617 | 23 | 20 626 | 41 | 199 (146 to 270) | 28 | 1.6% (1.1 to 2.4) | 48 | 0.85 (0.61 to 1.16) | |
| 3 | 1225 | 11 | 9870 | 19 | 193 (123 to 302) | 15 | 1.7% (1.0 to 2.9) | 24 | 0.79 (0.48 to 1.23) | |
| 4 | 596 | 5 | 4884 | 9 | 184 (96 to 354) | 6 | 1.2% (0.5 to 2.7) | 12 | 0.73 (0.33 to 1.38) | |
| ≥5 | 978 | 8 | 7930 | 24 | 303 (203 to 452) | 22 | 4.0% (2.5 to 6.3) | 21 | 1.17 (0.75 to 1.74) | |
| PMP size, mm§ | <0.001 | |||||||||
| <10 | 5608 | 48 | 44 221 | 54 | 122 (94 to 159) | 44 | 1.3% (0.9 to 1.7) | 93 | 0.58 (0.43 to 0.75) | |
| 10–19 | 3591 | 31 | 29 974 | 47 | 157 (118 to 209) | 39 | 1.5% (1.1 to 2.1) | 70 | 0.67 (0.50 to 0.90) | |
| ≥20 | 2366 | 20 | 19 991 | 53 | 265 (203 to 347) | 39 | 2.7% (1.9 to 3.7) | 48 | 1.10 (0.82 to 1.44) | |
| Adenoma histology¶ | <0.001 | |||||||||
| Tubular | 6526 | 56 | 52 399 | 54 | 103 (79 to 135) | 42 | 0.9% (0.7 to 1.3) | 114 | 0.48 (0.36 to 0.62) | |
| Tubulovillous | 3849 | 33 | 31 489 | 69 | 219 (173 to 277) | 57 | 2.4% (1.8 to 3.2) | 74 | 0.94 (0.73 to 1.19) | |
| Villous | 660 | 6 | 5453 | 17 | 312 (194 to 501) | 13 | 3.0% (1.7 to 5.5) | 14 | 1.21 (0.70 to 1.93) | |
| Unknown | 569 | 5 | 5225 | 14 | 268 (159 to 452) | 10 | 2.6% (1.4 to 5.0) | 11 | 1.23 (0.67 to 2.06) | |
| Adenoma dysplasia** | 0.05 | |||||||||
| Low grade | 9857 | 85 | 79 296 | 117 | 148 (123 to 177) | 92 | 1.5% (1.2 to 1.8) | 175 | 0.67 (0.55 to 0.80) | |
| High grade | 1389 | 12 | 11 539 | 28 | 243 (168 to 351) | 25 | 2.7% (1.8 to 4.1) | 29 | 0.95 (0.63 to 1.38) | |
| Unknown | 358 | 3 | 3731 | 9 | 241 (126 to 464) | 5 | 1.8% (0.7 to 4.3) | 8 | 1.10 (0.50 to 2.09) | |
| Proximal polyps†† | <0.001 | |||||||||
| No | 6195 | 53 | 51 440 | 64 | 124 (97 to 159) | 50 | 1.2% (0.9 to 1.7) | 109 | 0.59 (0.45 to 0.75) | |
| Yes | 5409 | 47 | 43 126 | 90 | 209 (170 to 257) | 72 | 2.1% (1.7 to 2.7) | 103 | 0.87 (0.70 to 1.07) | |
| No of APMPs and PMPs | <0.001 | |||||||||
| No APMPs, 1 PMP | 3402 | 29 | 26 997 | 27 | 100 (69 to 146) | 23 | 1.1% (0.7 to 1.7) | 54 | 0.50 (0.33 to 0.73) | |
| No APMPs, 2–4 PMPs | 1748 | 15 | 13 362 | 17 | 127 (79 to 205) | 11 | 1.0% (0.5 to 1.9) | 30 | 0.57 (0.33 to 0.91) | |
| No APMPs, ≥5 PMPs | 310 | 3 | 2566 | 6 | 234 (105 to 520) | 6 | 3.1% (1.4 to 7.2) | 6 | 0.95 (0.35 to 2.06) | |
| 1 APMP, no other PMPs | 2786 | 24 | 24 259 | 34 | 140 (100 to 196) | 28 | 1.5% (1.0 to 2.2) | 54 | 0.64 (0.44 to 0.89) | |
| ≥1 APMP, ≥2 total PMPs | 3358 | 29 | 27 382 | 70 | 256 (202 to 323) | 54 | 2.4% (1.8 to 3.3) | 69 | 1.02 (0.79 to 1.29) | |
*Cumulative CRC incidence was estimated using the Kaplan-Meier method.
†P values were calculated with the log-rank test to compare cumulative CRC incidence among each category of the specified variable.
‡Numbers of expected CRCs were calculated by multiplying the 5-year age-group and sex-specific observed person-years by the corresponding CRC incidence rates in the general population of England in 2007.
§PMP size was defined according to the largest PMP seen at baseline. Patients with PMPs of unknown size are not included in the table; in the analyses without surveillance, there were 59 such patients, of whom one was diagnosed with CRC; and in the analyses with one or more surveillance visits, there were 39 such patients with no CRC cases.
¶Adenoma histology was defined according to the greatest degree of villousness seen at baseline.
**Adenoma dysplasia was defined according to the highest grade of dysplasia seen at baseline.
††Proximal polyps were defined as those proximal to the descending colon.
APMP, advanced PMP; CRC, colorectal cancer; PMP, premalignant polyp; SIR, standardised incidence ratio.