Table 2.
Baseline characteristics of individuals with low-risk adenomas as defined by UK and EU/US guidelines
| Characteristic | UK definition* n=4516 | EU/US definition† n=2477 |
|---|---|---|
| Age (years, mean±SD) | 61.7±9.5 | 62.3±9.3 |
| Male (n, %) | 3205 (71.0) | 1825 (73.7) |
| Race (n, %) | ||
| White | 4034 (89.3) | 2227 (89.9) |
| Black | 237 (5.3) | 147 (5.9) |
| Other | 245 (5.4) | 103 (4.2) |
| Family history of colorectal cancer‡ (n, %) | ||
| Yes | 1054 (23.3) | 525 (21.2) |
| No | 3174 (70.3) | 1875 (75.7) |
| Unknown | 288 (6.4) | 77 (3.1) |
| Cigarette smoking status (n, %) | ||
| Never | 1562 (34.6) | 814 (32.9) |
| Former | 2241 (49.6) | 1261 (50.9) |
| Current | 691 (15.3) | 387 (15.6) |
| Unknown | 22 (0.5) | 15 (0.6) |
| Body mass index in kg/m2 (n, %)§ | ||
| <25 | 1297 (28.7) | 679 (27.4) |
| 25 to <30 | 2049 (45.4) | 1145 (46.2) |
| ≥30 | 1161 (25.7) | 650 (26.2) |
| Previous polyp (n, %)¶ | ||
| Yes | 1313 (29.1) | 641 (25.9) |
| No | 3113 (68.9) | 1780 (71.9) |
| Unknown | 90 (2.0) | 56 (2.3) |
| Adenoma characteristics | ||
| Number of adenomas (mean±SD) | 1.3±0.4 | 1.2±0.4 |
| Location of adenomas (n, %) | ||
| Distal/rectal only | 2201 (48.7) | 1224 (49.4) |
| Proximal only | 1754 (38.8) | 982 (39.6) |
| Proximal and distal | 397 (8.8) | 218 (8.8) |
| Unknown | 164 (3.6) | 53 (2.1) |
| Size of largest adenoma (mm, mean±SD) | 4.8±1.9 | 4.7±1.9 |
| Adenoma histology (n, %) | ||
| Tubular | 3579 (79.3) | 2477 (100.0) |
| Tubulovillous/villous | 386 (8.6) | 0 (0.0) |
| Unspecified | 551 (12.2)** | 0 (0.0) |
| High-grade dysplasia (%)†† | ||
| Yes | 119 (2.6) | 0 (0.0) |
| No | 3264 (72.4) | 2477 (100.0) |
Low-risk adenomas defined by UK guidelines as 1–2 adenomas <1 cm in diameter, regardless of histology or dysplasia grade.
Low-risk adenomas defined by US guidelines as 1–2 tubular adenomas <1 cm in diameter, without villous/tubulovillous histology and without high-grade dysplasia.
Family history of colorectal cancer in at least one first-degree relative. Participants with familial syndromes such as FAP or Lynch were excluded from the parent studies.
Body mass index (BMI) data not available (n=9).
History of polyps prior to qualifying exam.
Adenoma histology data not available for a subset of UK group patients; these were included in analysis because histology beyond presence of adenoma is not required to be part of UK low risk category.
HGD data not available (n=1133).
EU, European Union; HGD, high-grade dysplasia.