Findings at follow-up colonoscopy after randomisation (per-protocol analysis)
| Finding | 2-examination group | 1-examination group | P value | |
| First follow-up examination | Second follow-up examination | Follow-up examination | ||
| (n=701) | (n=763) | |||
| N (%) of patients | ||||
| Polyps | 295 (42.1) | 246 (35.1) | 331 (43.4) | <0.001 |
| Any neoplasia detected | 244 (34.8) | 218 (31.1) | 289 (37.9) | <0.001 |
| 351 (50.1) | ||||
| Size of largest neoplasia | ||||
| Small (≤5 mm) | 205 (29.2) | 168 (24.0) | 208 (27.3) | <0.001 |
| Medium (6–9 mm) | 34 (4.9) | 44 (6.3) | 67 (8.8) | 0.135 |
| Large (≥10 mm) | 5 (0.7) | 6 (0.9) | 14 (1.8) | 0.703 |
| Morphology* | ||||
| Polypoid (≥10 mm) | 2 (0.3) | 2 (0.3) | 3 (0.4) | 0.646 |
| Flat (<10 mm) | 143 (20.4) | 138 (19.7) | 170 (22.3) | <0.001 |
| Depressed | 2 (0.3) | 3 (0.4) | 8 (1.0) | 0.514 |
| LST-G | 0 (0) | 1 (0.1) | 1 (0.1) | 1.000 |
| LST-NG | 3 (0.4) | 2 (0.3) | 10 (1.3) | 0.272 |
| Villous component† | ||||
| Present | 0 (0) | 0 (0) | 1 (0.1) | 1.000 |
| Large serrated lesion (≥10 mm, Rt-sided‡) | ||||
| Present | 3 (0.4) | 4 (0.6) | 12 (1.6) | 0.345 |
| Dysplasia and invasive cancer§ | ||||
| Low-grade dysplasia | 240 (34.2) | 215 (30.7) | 279 (36.6) | <0.001 |
| High-grade dysplasia | 3 (0.4) | 2 (0.3) | 8 (1.0) | 0.514 |
| Invasive cancer | 0 (0) | 1 (0.1)¶ | 0 (0) | 0.958 |
| Others | 1 (0.1)** | 0 (0) | 2 (0.3)†† | 1.000 |
| Advanced neoplasia‡‡ | ||||
| No of lesions | 6 | 6 | 17 | 0.599 |
| No of patients | 12 (1.7) | 16 (2.1) | ||
*Polypoid; 0-Ip, 0-Isp, 0-Is type, Flat; 0-IIa type, Depressed; 0-IIa+IIc, 0-IIc type.
†Tubulovillous adenoma.
‡Caecum, ascending colon, transverse colon.
§Histology of worst lesion.
¶T2N0M0 (Duke’s stage B1) (online supplemental figure 1).
**1 Carcinoid tumour.
††1 Carcinoid tumour, 1 Malignant lymphoma.
‡‡Any lesion with low-grade dysplasia ≥10 mm, high-grade dysplasia or invasive cancer.
LST-G, laterally spreading tumour, granular type; LST-NG, laterally spreading tumour, non-granular type.