Table 5

Cumulative incidence of colorectal cancer and age-sex-standardised incidence ratios in high-risk patients (n=6239)

n%No of person-yearsNo of CRCsIncidence rate per 100 000 person-years (95% CI)At 10 yearsP value†Standardisation
No of CRCsCumulative incidence (95% CI)*No of expected CRCs‡SIR (95% CI)
After baseline (without surveillance, censored at any first surveillance visit)
Total623910025 79678302 (242 to 377)703.3% (2.5 to 4.3)601.30 (1.03 to 1.62)
Sex0.60
 Women222636995833331 (236 to 466)293.5% (2.3 to 5.3)181.79 (1.23 to 2.51)
 Men40136415 83945284 (212 to 381)413.2% (2.2 to 4.5)421.08 (0.79 to 1.45)
Age at baseline, years<0.001
 <558291339835126 (52 to 302)51.4% (0.6 to 3.6)22.27 (0.74 to 5.29)
 55–64176328708512169 (96 to 298)102.6% (1.3 to 5.2)111.08 (0.56 to 1.89)
 65–74230537890530337 (236 to 482)283.4% (2.2 to 5.3)251.20 (0.81 to 1.71)
 ≥75134222582331532 (374 to 757)275.2% (3.4 to 7.9)221.44 (0.97 to 2.04)
No of PMPs0.70
 1498819904201 (75 to 536)31.9% (0.6 to 6.2)50.83 (0.23 to 2.13)
 225304111 63835301 (216 to 419)313.1% (2.1 to 4.6)271.30 (0.90 to 1.81)
 3120819496713262 (152 to 451)112.9% (1.4 to 5.7)121.12 (0.59 to 1.91)
 46161023719380 (197 to 729)96.0% (2.9 to 12.2)61.60 (0.73 to 3.04)
 ≥5138722483017352 (219 to 566)163.7% (2.0 to 6.5)111.56 (0.91 to 2.49)
PMP size, mm§0.35
 <10568924757283 (135 to 593)73.2% (1.4 to 7.3)51.32 (0.53 to 2.72)
 10–1931005013 75736262 (189 to 363)322.9% (2.0 to 4.3)311.15 (0.81 to 1.59)
 ≥20253941945135370 (266 to 516)314.0% (2.6 to 6.0)231.52 (1.06 to 2.11)
Adenoma histology¶0.31
 Tubular24103910 70929271 (188 to 390)243.1% (2.0 to 4.7)241.21 (0.81 to 1.74)
 Tubulovillous29634711 75334289 (207 to 405)323.0% (2.0 to 4.5)281.21 (0.84 to 1.69)
 Villous68611265211415 (230 to 749)114.8% (2.3 to 9.8)71.64 (0.82 to 2.94)
 Unknown18036824587 (220 to 1563)37.0% (1.6 to 27.9)12.96 (0.81 to 7.57)
Adenoma dysplasia**<0.001
 Low grade47047520 15748238 (179 to 316)422.3% (1.6 to 3.2)461.04 (0.77 to 1.38)
 High grade140823505229574 (399 to 826)277.4% (4.9 to 11.1)132.28 (1.52 to 3.27)
 Unknown12725871170 (24 to 1208)15.6% (0.8 to 33.4)10.93 (0.02 to 5.19)
Proximal polyps††0.03
 No24754011 20725223 (151 to 330)232.4% (1.5 to 3.7)251.00 (0.64 to 1.47)
 Yes37646014 59053363 (278 to 476)474.1% (2.9 to 5.7)351.52 (1.14 to 1.99)
After first surveillance (with one surveillance visit, censored at any second surveillance visit)
Total396310017 53152297 (226 to 389)464.0% (2.8 to 5.8)431.22 (0.91 to 1.60)
Sex0.82
 Women136734637719298 (190 to 467)184.8% (2.7 to 8.6)111.67 (1.00 to 2.61)
 Men25966611 15433296 (210 to 416)283.4% (2.1 to 5.5)311.05 (0.73 to 1.48)
Age at baseline, years0.08
 <556161628468281 (141 to 562)72.5% (1.1 to 5.9)24.26 (1.84 to 8.39)
 55–6412993356099160 (83 to 308)93.0% (1.2 to 7.7)110.85 (0.39 to 1.61)
 65–74152939668423344 (229 to 518)193.6% (2.1 to 6.1)211.10 (0.70 to 1.65)
 ≥7551913239212502 (285 to 883)117.9% (4.0 to 15.3)91.29 (0.67 to 2.25)
No of PMPs0.89
 1295713083229 (74 to 711)34.4% (1.2 to 15.0)30.90 (0.19 to 2.63)
 2152138713022309 (203 to 469)194.3% (2.4 to 7.6)171.29 (0.81 to 1.95)
 37671933148241 (121 to 483)83.3% (1.4 to 7.6)81.00 (0.43 to 1.97)
 44021018066332 (149 to 739)41.6% (0.5 to 4.8)51.33 (0.49 to 2.89)
 ≥597825397313327 (190 to 564)125.5% (2.5 to 11.9)101.33 (0.71 to 2.28)
PMP size, mm§0.86
 <10375916376367 (165 to 816)65.6% (2.0 to 15.2)41.54 (0.57 to 3.36)
 10–19191748875724274 (184 to 409)223.4% (2.0 to 5.8)211.15 (0.74 to 1.71)
 ≥20164942706822311 (205 to 473)184.3% (2.4 to 7.7)181.24 (0.78 to 1.88)
Adenoma histology¶0.22
 Tubular151038682013191 (111 to 328)122.2% (1.0 to 4.4)160.81 (0.43 to 1.39)
 Tubulovillous189348829329350 (243 to 503)265.9% (3.6 to 9.5)201.42 (0.95 to 2.04)
 Villous4431118968422 (211 to 844)73.6% (1.7 to 7.7)51.56 (0.67 to 3.07)
 Unknown11735222383 (96 to 1533)11.1% (0.2 to 7.8)11.77 (0.21 to 6.38)
Adenoma dysplasia**0.12
 Low grade29457413 07932245 (173 to 346)283.7% (2.3 to 5.9)311.03 (0.70 to 1.45)
 High grade92723397117428 (266 to 689)165.3% (2.7 to 10.3)101.63 (0.95 to 2.61)
 Unknown9124813623 (201 to 1933)23.8% (0.9 to 15.3)12.75 (0.57 to 8.04)
Proximal polyps††0.10
 No154639715716224 (137 to 365)153.0% (1.5 to 5.7)170.96 (0.55 to 1.55)
 Yes24176110 37436347 (250 to 481)314.7% (3.0 to 7.4)261.39 (0.97 to 1.92)
After second surveillance (with two or more surveillance visits, censored at end of follow-up)
Total225910014 99032213 (151 to 302)252.3% (1.5 to 3.5)390.82 (0.56 to 1.16)
Sex0.57
 Women74133506710197 (106 to 367)82.1% (1.0 to 4.3)91.07 (0.51 to 1.97)
 Men151867992322222 (146 to 337)172.4% (1.4 to 4.1)300.74 (0.47 to 1.12)
Age at baseline, years0.05
 <55402183036399 (32 to 306)31.6% (0.5 to 5.1)30.96 (0.20 to 2.79)
 55–6483437571910175 (94 to 325)61.2% (0.5 to 3.0)140.72 (0.35 to 1.32)
 65–7487139545016294 (180 to 479)133.5% (1.9 to 6.3)190.86 (0.49 to 1.39)
 ≥7515277853382 (123 to 1185)34.9% (1.2 to 18.4)30.93 (0.19 to 2.73)
No of PMPs0.31
 1171812665395 (164 to 949)43.2% (1.2 to 8.8)31.51 (0.49 to 3.53)
 27933551008157 (78 to 314)51.3% (0.5 to 3.4)130.63 (0.27 to 1.24)
 34642130927226 (108 to 475)51.9% (0.8 to 4.8)80.87 (0.35 to 1.79)
 4242111576163 (9 to 450)10.8% (0.1 to 5.2)40.24 (0.01 to 1.35)
 ≥558926395711278 (154 to 502)104.1% (2.1 to 8.1)111.02 (0.51 to 1.83)
PMP size, mm§0.29
 <10210914503207 (67 to 641)32.6% (0.8 to 8.7)40.81 (0.17 to 2.37)
 10–1910634766989134 (70 to 258)71.1% (0.5 to 2.3)170.52 (0.24 to 0.99)
 ≥2096843669220299 (193 to 463)153.4% (1.9 to 5.8)181.14 (0.70 to 1.76)
Adenoma histology¶0.11
 Tubular8543857048140 (70 to 280)71.2% (0.5 to 2.6)150.55 (0.24 to 1.08)
 Tubulovillous107548699914200 (118 to 338)101.9% (1.0 to 3.7)180.77 (0.42 to 1.28)
 Villous2591116977412 (197 to 865)76.9% (3.1 to 15.1)51.55 (0.62 to 3.19)
 Unknown7135893509 (164 to 1578)12.9% (0.4 to 19.1)21.99 (0.41 to 5.83)
Adenoma dysplasia**0.75
 Low grade16817411 00422200 (132 to 304)182.0% (1.2 to 3.3)280.78 (0.49 to 1.18)
 High grade5252335098228 (114 to 456)73.5% (1.6 to 7.8)90.85 (0.37 to 1.67)
 Unknown5324772419 (105 to 1675)011.50 (0.18 to 5.41)
Proximal polyps††0.21
 No8533857589156 (81 to 300)61.2% (0.5 to 2.8)150.62 (0.28 to 1.18)
 Yes140662923223249 (166 to 375)192.9% (1.8 to 4.8)240.94 (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.