Table 5.
Cumulative incidence of colorectal cancer and age-sex-standardised incidence ratios in high-risk patients (n=6239)
| 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 | 6239 | 100 | 25 796 | 78 | 302 (242 to 377) | 70 | 3.3% (2.5 to 4.3) | 60 | 1.30 (1.03 to 1.62) | |
| Sex | 0.60 | |||||||||
| Women | 2226 | 36 | 9958 | 33 | 331 (236 to 466) | 29 | 3.5% (2.3 to 5.3) | 18 | 1.79 (1.23 to 2.51) | |
| Men | 4013 | 64 | 15 839 | 45 | 284 (212 to 381) | 41 | 3.2% (2.2 to 4.5) | 42 | 1.08 (0.79 to 1.45) | |
| Age at baseline, years | <0.001 | |||||||||
| <55 | 829 | 13 | 3983 | 5 | 126 (52 to 302) | 5 | 1.4% (0.6 to 3.6) | 2 | 2.27 (0.74 to 5.29) | |
| 55–64 | 1763 | 28 | 7085 | 12 | 169 (96 to 298) | 10 | 2.6% (1.3 to 5.2) | 11 | 1.08 (0.56 to 1.89) | |
| 65–74 | 2305 | 37 | 8905 | 30 | 337 (236 to 482) | 28 | 3.4% (2.2 to 5.3) | 25 | 1.20 (0.81 to 1.71) | |
| ≥75 | 1342 | 22 | 5823 | 31 | 532 (374 to 757) | 27 | 5.2% (3.4 to 7.9) | 22 | 1.44 (0.97 to 2.04) | |
| No of PMPs | 0.70 | |||||||||
| 1 | 498 | 8 | 1990 | 4 | 201 (75 to 536) | 3 | 1.9% (0.6 to 6.2) | 5 | 0.83 (0.23 to 2.13) | |
| 2 | 2530 | 41 | 11 638 | 35 | 301 (216 to 419) | 31 | 3.1% (2.1 to 4.6) | 27 | 1.30 (0.90 to 1.81) | |
| 3 | 1208 | 19 | 4967 | 13 | 262 (152 to 451) | 11 | 2.9% (1.4 to 5.7) | 12 | 1.12 (0.59 to 1.91) | |
| 4 | 616 | 10 | 2371 | 9 | 380 (197 to 729) | 9 | 6.0% (2.9 to 12.2) | 6 | 1.60 (0.73 to 3.04) | |
| ≥5 | 1387 | 22 | 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§ | 0.35 | |||||||||
| <10 | 568 | 9 | 2475 | 7 | 283 (135 to 593) | 7 | 3.2% (1.4 to 7.3) | 5 | 1.32 (0.53 to 2.72) | |
| 10–19 | 3100 | 50 | 13 757 | 36 | 262 (189 to 363) | 32 | 2.9% (2.0 to 4.3) | 31 | 1.15 (0.81 to 1.59) | |
| ≥20 | 2539 | 41 | 9451 | 35 | 370 (266 to 516) | 31 | 4.0% (2.6 to 6.0) | 23 | 1.52 (1.06 to 2.11) | |
| Adenoma histology¶ | 0.31 | |||||||||
| Tubular | 2410 | 39 | 10 709 | 29 | 271 (188 to 390) | 24 | 3.1% (2.0 to 4.7) | 24 | 1.21 (0.81 to 1.74) | |
| Tubulovillous | 2963 | 47 | 11 753 | 34 | 289 (207 to 405) | 32 | 3.0% (2.0 to 4.5) | 28 | 1.21 (0.84 to 1.69) | |
| Villous | 686 | 11 | 2652 | 11 | 415 (230 to 749) | 11 | 4.8% (2.3 to 9.8) | 7 | 1.64 (0.82 to 2.94) | |
| Unknown | 180 | 3 | 682 | 4 | 587 (220 to 1563) | 3 | 7.0% (1.6 to 27.9) | 1 | 2.96 (0.81 to 7.57) | |
| Adenoma dysplasia** | <0.001 | |||||||||
| Low grade | 4704 | 75 | 20 157 | 48 | 238 (179 to 316) | 42 | 2.3% (1.6 to 3.2) | 46 | 1.04 (0.77 to 1.38) | |
| High grade | 1408 | 23 | 5052 | 29 | 574 (399 to 826) | 27 | 7.4% (4.9 to 11.1) | 13 | 2.28 (1.52 to 3.27) | |
| Unknown | 127 | 2 | 587 | 1 | 170 (24 to 1208) | 1 | 5.6% (0.8 to 33.4) | 1 | 0.93 (0.02 to 5.19) | |
| Proximal polyps†† | 0.03 | |||||||||
| No | 2475 | 40 | 11 207 | 25 | 223 (151 to 330) | 23 | 2.4% (1.5 to 3.7) | 25 | 1.00 (0.64 to 1.47) | |
| Yes | 3764 | 60 | 14 590 | 53 | 363 (278 to 476) | 47 | 4.1% (2.9 to 5.7) | 35 | 1.52 (1.14 to 1.99) | |
| After first surveillance (with one surveillance visit, censored at any second surveillance visit) | ||||||||||
| Total | 3963 | 100 | 17 531 | 52 | 297 (226 to 389) | 46 | 4.0% (2.8 to 5.8) | 43 | 1.22 (0.91 to 1.60) | |
| Sex | 0.82 | |||||||||
| Women | 1367 | 34 | 6377 | 19 | 298 (190 to 467) | 18 | 4.8% (2.7 to 8.6) | 11 | 1.67 (1.00 to 2.61) | |
| Men | 2596 | 66 | 11 154 | 33 | 296 (210 to 416) | 28 | 3.4% (2.1 to 5.5) | 31 | 1.05 (0.73 to 1.48) | |
| Age at baseline, years | 0.08 | |||||||||
| <55 | 616 | 16 | 2846 | 8 | 281 (141 to 562) | 7 | 2.5% (1.1 to 5.9) | 2 | 4.26 (1.84 to 8.39) | |
| 55–64 | 1299 | 33 | 5609 | 9 | 160 (83 to 308) | 9 | 3.0% (1.2 to 7.7) | 11 | 0.85 (0.39 to 1.61) | |
| 65–74 | 1529 | 39 | 6684 | 23 | 344 (229 to 518) | 19 | 3.6% (2.1 to 6.1) | 21 | 1.10 (0.70 to 1.65) | |
| ≥75 | 519 | 13 | 2392 | 12 | 502 (285 to 883) | 11 | 7.9% (4.0 to 15.3) | 9 | 1.29 (0.67 to 2.25) | |
| No of PMPs | 0.89 | |||||||||
| 1 | 295 | 7 | 1308 | 3 | 229 (74 to 711) | 3 | 4.4% (1.2 to 15.0) | 3 | 0.90 (0.19 to 2.63) | |
| 2 | 1521 | 38 | 7130 | 22 | 309 (203 to 469) | 19 | 4.3% (2.4 to 7.6) | 17 | 1.29 (0.81 to 1.95) | |
| 3 | 767 | 19 | 3314 | 8 | 241 (121 to 483) | 8 | 3.3% (1.4 to 7.6) | 8 | 1.00 (0.43 to 1.97) | |
| 4 | 402 | 10 | 1806 | 6 | 332 (149 to 739) | 4 | 1.6% (0.5 to 4.8) | 5 | 1.33 (0.49 to 2.89) | |
| ≥5 | 978 | 25 | 3973 | 13 | 327 (190 to 564) | 12 | 5.5% (2.5 to 11.9) | 10 | 1.33 (0.71 to 2.28) | |
| PMP size, mm§ | 0.86 | |||||||||
| <10 | 375 | 9 | 1637 | 6 | 367 (165 to 816) | 6 | 5.6% (2.0 to 15.2) | 4 | 1.54 (0.57 to 3.36) | |
| 10–19 | 1917 | 48 | 8757 | 24 | 274 (184 to 409) | 22 | 3.4% (2.0 to 5.8) | 21 | 1.15 (0.74 to 1.71) | |
| ≥20 | 1649 | 42 | 7068 | 22 | 311 (205 to 473) | 18 | 4.3% (2.4 to 7.7) | 18 | 1.24 (0.78 to 1.88) | |
| Adenoma histology¶ | 0.22 | |||||||||
| Tubular | 1510 | 38 | 6820 | 13 | 191 (111 to 328) | 12 | 2.2% (1.0 to 4.4) | 16 | 0.81 (0.43 to 1.39) | |
| Tubulovillous | 1893 | 48 | 8293 | 29 | 350 (243 to 503) | 26 | 5.9% (3.6 to 9.5) | 20 | 1.42 (0.95 to 2.04) | |
| Villous | 443 | 11 | 1896 | 8 | 422 (211 to 844) | 7 | 3.6% (1.7 to 7.7) | 5 | 1.56 (0.67 to 3.07) | |
| Unknown | 117 | 3 | 522 | 2 | 383 (96 to 1533) | 1 | 1.1% (0.2 to 7.8) | 1 | 1.77 (0.21 to 6.38) | |
| Adenoma dysplasia** | 0.12 | |||||||||
| Low grade | 2945 | 74 | 13 079 | 32 | 245 (173 to 346) | 28 | 3.7% (2.3 to 5.9) | 31 | 1.03 (0.70 to 1.45) | |
| High grade | 927 | 23 | 3971 | 17 | 428 (266 to 689) | 16 | 5.3% (2.7 to 10.3) | 10 | 1.63 (0.95 to 2.61) | |
| Unknown | 91 | 2 | 481 | 3 | 623 (201 to 1933) | 2 | 3.8% (0.9 to 15.3) | 1 | 2.75 (0.57 to 8.04) | |
| Proximal polyps†† | 0.10 | |||||||||
| No | 1546 | 39 | 7157 | 16 | 224 (137 to 365) | 15 | 3.0% (1.5 to 5.7) | 17 | 0.96 (0.55 to 1.55) | |
| Yes | 2417 | 61 | 10 374 | 36 | 347 (250 to 481) | 31 | 4.7% (3.0 to 7.4) | 26 | 1.39 (0.97 to 1.92) | |
| After second surveillance (with two or more surveillance visits, censored at end of follow-up) | ||||||||||
| Total | 2259 | 100 | 14 990 | 32 | 213 (151 to 302) | 25 | 2.3% (1.5 to 3.5) | 39 | 0.82 (0.56 to 1.16) | |
| Sex | 0.57 | |||||||||
| Women | 741 | 33 | 5067 | 10 | 197 (106 to 367) | 8 | 2.1% (1.0 to 4.3) | 9 | 1.07 (0.51 to 1.97) | |
| Men | 1518 | 67 | 9923 | 22 | 222 (146 to 337) | 17 | 2.4% (1.4 to 4.1) | 30 | 0.74 (0.47 to 1.12) | |
| Age at baseline, years | 0.05 | |||||||||
| <55 | 402 | 18 | 3036 | 3 | 99 (32 to 306) | 3 | 1.6% (0.5 to 5.1) | 3 | 0.96 (0.20 to 2.79) | |
| 55–64 | 834 | 37 | 5719 | 10 | 175 (94 to 325) | 6 | 1.2% (0.5 to 3.0) | 14 | 0.72 (0.35 to 1.32) | |
| 65–74 | 871 | 39 | 5450 | 16 | 294 (180 to 479) | 13 | 3.5% (1.9 to 6.3) | 19 | 0.86 (0.49 to 1.39) | |
| ≥75 | 152 | 7 | 785 | 3 | 382 (123 to 1185) | 3 | 4.9% (1.2 to 18.4) | 3 | 0.93 (0.19 to 2.73) | |
| No of PMPs | 0.31 | |||||||||
| 1 | 171 | 8 | 1266 | 5 | 395 (164 to 949) | 4 | 3.2% (1.2 to 8.8) | 3 | 1.51 (0.49 to 3.53) | |
| 2 | 793 | 35 | 5100 | 8 | 157 (78 to 314) | 5 | 1.3% (0.5 to 3.4) | 13 | 0.63 (0.27 to 1.24) | |
| 3 | 464 | 21 | 3092 | 7 | 226 (108 to 475) | 5 | 1.9% (0.8 to 4.8) | 8 | 0.87 (0.35 to 1.79) | |
| 4 | 242 | 11 | 1576 | 1 | 63 (9 to 450) | 1 | 0.8% (0.1 to 5.2) | 4 | 0.24 (0.01 to 1.35) | |
| ≥5 | 589 | 26 | 3957 | 11 | 278 (154 to 502) | 10 | 4.1% (2.1 to 8.1) | 11 | 1.02 (0.51 to 1.83) | |
| PMP size, mm§ | 0.29 | |||||||||
| <10 | 210 | 9 | 1450 | 3 | 207 (67 to 641) | 3 | 2.6% (0.8 to 8.7) | 4 | 0.81 (0.17 to 2.37) | |
| 10–19 | 1063 | 47 | 6698 | 9 | 134 (70 to 258) | 7 | 1.1% (0.5 to 2.3) | 17 | 0.52 (0.24 to 0.99) | |
| ≥20 | 968 | 43 | 6692 | 20 | 299 (193 to 463) | 15 | 3.4% (1.9 to 5.8) | 18 | 1.14 (0.70 to 1.76) | |
| Adenoma histology¶ | 0.11 | |||||||||
| Tubular | 854 | 38 | 5704 | 8 | 140 (70 to 280) | 7 | 1.2% (0.5 to 2.6) | 15 | 0.55 (0.24 to 1.08) | |
| Tubulovillous | 1075 | 48 | 6999 | 14 | 200 (118 to 338) | 10 | 1.9% (1.0 to 3.7) | 18 | 0.77 (0.42 to 1.28) | |
| Villous | 259 | 11 | 1697 | 7 | 412 (197 to 865) | 7 | 6.9% (3.1 to 15.1) | 5 | 1.55 (0.62 to 3.19) | |
| Unknown | 71 | 3 | 589 | 3 | 509 (164 to 1578) | 1 | 2.9% (0.4 to 19.1) | 2 | 1.99 (0.41 to 5.83) | |
| Adenoma dysplasia** | 0.75 | |||||||||
| Low grade | 1681 | 74 | 11 004 | 22 | 200 (132 to 304) | 18 | 2.0% (1.2 to 3.3) | 28 | 0.78 (0.49 to 1.18) | |
| High grade | 525 | 23 | 3509 | 8 | 228 (114 to 456) | 7 | 3.5% (1.6 to 7.8) | 9 | 0.85 (0.37 to 1.67) | |
| Unknown | 53 | 2 | 477 | 2 | 419 (105 to 1675) | 0 | – | 1 | 1.50 (0.18 to 5.41) | |
| Proximal polyps†† | 0.21 | |||||||||
| No | 853 | 38 | 5758 | 9 | 156 (81 to 300) | 6 | 1.2% (0.5 to 2.8) | 15 | 0.62 (0.28 to 1.18) | |
| Yes | 1406 | 62 | 9232 | 23 | 249 (166 to 375) | 19 | 2.9% (1.8 to 4.8) | 24 | 0.94 (0.60 to 1.41) | |
High-risk patients were those with ≥2 PMPs, of which ≥1 was advanced, ≥5 PMPs or ≥1 large (≥20 mm) non-pedunculated PMP.
*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 32 such patients with no CRC cases; in the analyses with one surveillance visit, there were 22 such patients with no CRC cases; and in the analyses with two or more surveillance visits, there were 18 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.
CRC, colorectal cancer; PMP, premalignant polyp; SIR, standardised incidence ratio.