High total Joule heat increases the risk of post-endoscopic submucosal dissection electrocoagulation syndrome after colorectal endoscopic submucosal dissection

Table 1 Characteristics of patients who underwent endoscopic submucosal dissection, n (%)

Patient features	n (%)
Number of patients	151
Male	94 (62.3)
Age (yr), mean ± SD	67.3 ± 10.9
BMI (kg/m2), mean ± SD	22.9 ± 3.0
Specimen size
< 40 mm	132 (87.4)
≥ 40 mm	19 (12.6)
Total Joule heat
< 8460 J1	75 (49.7)
≥ 8460 J	76 (50.3)
Tumor location
Right colon	59 (39.1)
Left colon	41 (27.1)
Rectum	51 (33.8)
Tumor morphology
0-Is/Ip	29 (19.2)
LST-G	75 (49.7)
LST-NG (0-IIc)	47 (31.1)
Depth of pathological invasion
Tis (M)	130 (86.1)
T1 (SM)	21 (13.9)
Histological diagnosis
Adenoma	67 (44.4)
Adenocarcinoma	80 (53.0)
Other	4 (2.6)
ECOG performance status after ESD
0	144 (95.4)
≥1	7 (4.6)
R0 resection	115 (76.2)
ESD procedure performed by trainees	52 (34.4)
Additional endoscopic therapy after ESD	2 (1.3)
Additional surgery after ESD	12 (7.9)
En bloc resection	135 (89.4)
Intraoperative perforation or penetration	7 (4.6)
Submucosal fibrosis	45 (29.8)
PECS	16 (10.6)

¹Patients exposed to more or less than the median Joule heat value (8460 J) were assigned to the high and low Joule heat groups, respectively.

BMI: Body mass index; Is: Sessile type; Ip: Pedunculated type; LST-G: Lateral spreading tumor granular type; LST-NG: Lateral spreading tumor non-granular type; IIc: Superficial depressed type; Tis (M): Carcinoma in situ or intramucosal carcinoma; T1 (SM): Tumor invades submucosa; R0: Microscopically margin-negative; ESD: Endoscopic submucosal dissection; PECS: Post-endoscopic submucosal dissection electrocoagulation syndrome; SD: Standard deviation; ECOG performance status: Eastern Cooperative Oncology Group performance status.

Table 2 Clinicopathological factors in the high and low Joule heat groups, n (%)

	High Joule heat	Low Joule heat	P value
	n = 76	n = 75
Sex			0.54
Male	45 (59.2)	49 (65.3)
Female	31 (40.8)	26 (34.7)
Age (yr), mean ± SD	69 ± 11.5	66 ± 10.2	< 0.01
BMI (kg/m2), mean ± SD	22.8 ± 2.3	23.0 ± 3.2	0.77
Specimen size			< 0.01
< 40 mm	60 (78.9)	73 (97.3)
≥ 40 mm	16 (21.1)	2 (2.7)
Tumor location			0.84
Right colon	28 (36.9)	31 (41.3)
Left colon	21 (27.6)	20 (26.7)
Rectum	27 (35.5)	24 (32.0)
Tumor morphology			0.56
0-Is/Ip	18 (23.7)	21 (28.0)
LST-G	36 (47.4)	29 (38.7)
LST-NG (0-IIc)	22 (28.9)	25 (33.3)
Depth of pathological invasion			0.66
Tis (M)	64 (84.2)	66 (88.0)
T1 (SM)	12 (15.8)	9 (12.0)
Histological diagnosis			0.12
Adenoma	34 (44.7)	33 (44.0)
Adenocarcinoma	42 (55.3)	38 (50.7)
Other	0 (0.0)	4 (5.3)
Performance status after ESD			0.45
0	71 (93.4)	73 (97.3)
≥ 1	5 (6.6)	2 (2.7)
R0 resection	50 (65.8)	65 (86.7)	< 0.01
ESD procedure performed by trainees	37 (55.3)	15 (13.3)	< 0.01
Additional endoscopic therapy after ESD	1 (1.3)	1 (1.3)	0.999
Additional surgery after ESD	8 (10.5)	4 (5.3)	0.38
En bloc resection	69 (90.8)	73 (97.3)	0.18
Submucosal fibrosis	27 (35.5)	18 (24.0)	0.17
PECS	13 (17.1)	3 (4.0)	0.02

BMI: Body mass index; Is: Sessile type; Ip: Pedunculated type; LST-G: Lateral spreading tumor granular type; LST-NG: Lateral spreading tumor non-granular type; IIc: Superficial depressed type; Tis (M): Carcinoma in situ or intramucosal carcinoma; T1 (SM): Tumor invades submucosa; R0: Microscopically margin-negative; ESD: Endoscopic submucosal dissection; PECS: Post-endoscopic submucosal dissection electrocoagulation syndrome; SD: Standard deviation.

Table 3 Multivariate analysis of risk factors associated with high Joule heat accumulation

	Odds ratio	95%CI	P value
Age	1.03	0.99-1.06	0.17
R0 resection	3.27	1.26-8.45	0.01
Specimen size	1.07	1.03-1.11	< 0.01
ESD procedure performed by trainees	5.30	2.32-12.10	< 0.01
PECS	4.83	1.08-21.50	0.03

PECS: Post-endoscopic submucosal dissection electrocoagulation syndrome; R0: Microscopically margin-negative; 95% CI: 95% confidence interval.