Risk factors for local recurrence and appropriate surveillance interval after endoscopic resection

Table 1 Univariate analysis of risk factors for local recurrence

Factors	Recurrence	Odds ratio	95%CI	P value
Age
< 60 yr	2/60	1
≥ 60 yr	29/300	3.07	0.73-12.8	0.12
Sex
Male	24/228	1
Female	7/132	0.48	0.21-1.11	0.09
History of CRC
-	31/341	1
+	0/19	0.046	0-50.0	0.38
Diabetes
-	29/338	1
+	2/22	1.07	0.25-4.49	0.92
Growth type
LST-G	8/58	1
LST-NG	9/47	1.395	0.53-3.61	0.49
II a, II c	1/45	0.693	0.34-1.38	0.30
Ip, Is	13/210	0.655	0.42-1.01	0.06
Size
< 2 cm	11/239	1
≥ 2 cm	20/121	3.77	1.80-7.88	< 0.001
Location
Rectum	4/67	1
Colon	27/293	0.626	0.21-1,79	0.38
Resection methods
En bloc	6/297	1
Piecemeal	25/63	23.7	9.72-57.8	< 0.001
No of adenoma
< 3	19/227	1
≥ 3	12/133	1.09	0.53-2.26	0.79
Histology
Low grade adenoma	18/159	1
High grade adenoma	12/163	0.65	0.31-1.36	0.26
T1 carcinoma or deeper	1/38	0.46	0.17-1.27	0.13
Histology villous type
-	25/333	1
+	6/27	2.09	1.10-3.97	0.023

CI: Confidence interval; CRC: Colorectal cancer; LST-G: Laterally spreading tumor granular type; LST-NG: Laterally spreading tumor non granular type; Ip: Pedunculated; Is: Sessile.

Table 2 Multivariate analysis of risk factors for local recurrence

Factors	Odds ratio	95%CI	P value
Size ≥ 2 cm	0.93	0.41-2.11	0.87
Histology villous type	1.03	0.51-2.07	1.03
Piecemeal resection	24.3	9.07-65.4	< 0.001

CI: Confidence interval.

Table 3 Recurrence rate for the different types of techniques

Therapy	Recurrence rate (recurrence/total)
Polypectomy	0% (0/29)
En bloc EMR	2.4% (5/209)
Piecemeal EMR	36.6% (15/41)
En bloc ESD	1.7% (1/60)
Piecemeal ESD	52.4% (11/21)

EMR: Endoscopic mucosal resection; ESD: Endoscopic submucosal dissection.

Table 4 Number of pieces and time to recurrence

No of pieces	Time to recurrence (average months)
1 piece but unclear margin (6 cases)	6.0 ± 1.4
2 pieces (5 cases)	9.0 ± 3.8
3 pieces (7 cases)	10.1 ± 6.3
4 pieces (1 case)	5
≥ 5 pieces (12 cases)	3.8 ± 1.9

Table 5 Recommendation of interval before repeat colonoscopy

Interval before a repeat colonoscopy
1-3 mo after piecemeal resection ≥ 5 pieces (high risk for recurrence)
4-6 mo after piecemeal resection ≤ 4 pieces (moderate risk for recurrence)
6 mo after en bloc resection for cancer (low risk for recurrence)
≥ 12 mo after en bloc resection for adenoma (very low risk for recurrence)