Meta-analysis of short-term outcomes after laparoscopy-assisted distal gastrectomy

Table 1 Trials included in the meta-analysis

			n		Level of lymph
Ref.	Yr	Country	LADG	CODG	node dissection	Participants in LADG
Prospective randomized controlled trials
6	2002	Japan	14	14	D1 + α	Patients with EGC in whom EMR was not indicated
7	2005	Korea	24	23	D2	Patients with preoperatively diagnosed mucosal or submucosal cancer
8	2005	Italy	30	29	D1, D2	Patients who presented with metastatic tumor or with tumor extension beyond the distal stomach were excluded.
9	2005	Japan	14	14	D1 + α	Patients with EGC assumed to infiltrate the mucosa or submucosa
Retrospective studies
10	2000	Japan	49	53	D1 + α	Patients with EGC assumed to infiltrate the mucosa or submucosa
11	2000	Japan	21	31	D1 + α	Patients with EGC assumed to infiltrate the mucosa
12	2001	Japan	24	35	D1 + α	Patients with preoperatively diagnosed mucosal or submucosal cancer; those with deep submucosal cancer were excluded.
13	2003	Japan	10	17	D1 + α	Patients with EGC assumed to infiltrate the mucosa or submucosa
14	2005	Japan	37	31	D2	Patients with EGC assumed to infiltrate the mucosa or submucosa, and those diagnosed with advanced cancer without lymph node metastasis
15	2005	Japan	235	200	D2	Patients with preoperatively diagnosed gastric cancer assumed to be confined to the muscular layer without lymph node metastasis
16	2005	Japan	89	60	D1 + β	Patients with preoperatively diagnosed EGC assumed to infiltrate the mucosa or submucosa without lymph node metastasis
17	2005	Japan	20	22	D1 + α, D1 + β	Patients with preoperatively diagnosed EGC assumed to infiltrate the mucosa or submucosa without lymph node metastasis
18	2005	Korea	71	76	D1 + α, D1 + β, D2	Patients with mucosal cancer indicated for EMR were excluded.
19	2005	Korea	16	16	D2	Patients with EGC assumed to infiltrate the mucosa or submucosa
20	2006	Japan	47	33	D1 + β	Patients with EGC assumed to infiltrate the mucosa
21	2006	Korea	136	120	D1 + α, D1 + β, D2	Patients with preoperatively diagnosed EGC

LADG: Laparoscopy-assisted distal gastrectomy; CODG: Conventional open distal gastrectomy; EGC: Early gastric cancer; D1: Perigastric lymph nodes; D1 + α: Perigastric lymph nodes and lymph nodes along the left gastric artery; D1 + β: Perigastric lymph nodes and lymph nodes along the left gastric artery and the celiac axis; D2: Perigastric lymph nodes and lymph nodes along the left gastric, common hepatic, proper hepatic, celiac, and splenic arteries; EMR: Endoscopic mucosal resection.

Table 2 Operative findings

Outcome	Type of studiesincluded in themeta-analysis	Trials(n)	Patients(n)	Pooled resultsWMD (95% CI)	Interpretation	Test forheterogeneity
Operating time	RCTs	4	162	83.1 (40.5, 125.6) Z = 3.83, P < 0.001	L > C	χ2 = 91.9, df = 3 P < 0.001, I2 = 96.7%
	Overall	16	1611	54.3 (38.8, 69.8) Z = 6.88, P < 0.001	L > C	χ2 = 620.9, df = 15 P < 0.001, I2 = 97.6%
Blood loss	RCTs	4	162	-104.3 (-189.0, -19.5) Z = 2.41, P = 0.02	L < C	χ2 = 13.6, df = 3 P = 0.004, I2 = 77.9%
	Overall	15	1464	-145.6 (-181.4, -109.9) Z = 7.99, P < 0.001	L < C	χ2 = 280.4, df = 14 P < 0.001, I2 = 95.0%
No. of Lymph nodes dissected	RCTs	4	162	-4.34 (-6.66, -2.02) Z = 3.66, P < 0.001	L < C	χ2 = 1.68, df = 3 P = 0.64, I2 = 0%
	Overall	14	1482	-4.35 (-5.73, -2.98) Z = 6.20, P < 0.001	L < C	χ2 = 34.8, df = 13 P = 0.001, I2= 62.7%

L: Laparoscopy-assisted distal gastrectomy; C: Conventional open distal gastrectomy; RCTs: Randomized controlled trials; WMD: Weighted mean difference; CI: Confidence intervals; df: Degree of freedom.

Table 3 Morbidity and mortality

Outcome	Type of studiesincluded in themeta-analysis	Trials(n)	LADG		CODG		Pooled resultsOR (95% CI)	Interpretation	Test forheterogeneity
			Events	Patients(n)	Events	Patients(n)
Overall complications	RCTs	4	16	82	30	80	0.41 (0.20, 0.85) Z = 2.41, P = 0.02	L < C	χ2 = 2.52, df = 3 P = 0.47, I2 = 0%
	Overall	13	58	535	97	519	0.54 (0.37, 0.77) Z = 3.37, P < 0.001	L < C	χ2 = 9.11, df = 12 P = 0.69, I2 = 0%
Anastomotic leakage	RCTs	2	0	44	3	43	0.23 (0.02, 2.18) Z = 1.28, P = 0.20	L = C	χ2 = 0.07, df = 1 P = 0.80, I2 = 0%
	Overall	7	2	385	10	365	0.38 (0.12, 1.18) Z = 1.67, P = 0.10	L = C	χ2 = 0.96, df = 6 P = 0.99, I2 = 0%
Anastomotic stenosis	RCTs	2	0	38	2	37	0.31 (0.03, 3.11) Z = 1.00, P = 0.32	L = C	χ2 = 0.00, df = 1 P = 1.00, I2 = 0%
	Overall	5	6	172	5	163	1.11 (0.35, 3.54) Z = 0.18, P = 0.86	L = C	χ2 = 2.01, df = 4 P = 0.73, I2 = 0%
Postoperative ileus	Overall	6	2	267	13	264	0.27 (0.09, 0.84) Z = 2.26, P = 0.02	L < C	χ2 = 1.40, df = 5 P = 0.92, I2 = 0%
Pulmonary complications	RCTs	4	10	82	19	80	0.47 (0.20, 1.12) Z = 1.70, P = 0.09	L = C	χ2 = 1.95, df = 3 P = 0.58, I2 = 0%
	Overall	8	12	260	22	271	0.54 (0.25, 1.15) Z = 1.59, P = 0.11	L = C	χ2 = 3.66, df = 7 P = 0.82, I2 = 0%
Wound infection	RCTs	2	3	54	3	52	0.96 (0.18, 5.01) Z = 0.05, P = 0.96	L = C	χ2 = 0.05, df = 1 P = 1.00, I2 = 0%
	Overall	9	9	448	13	421	0.69 (0.30, 1.57) Z = 0.89, P = 0.37	L = C	χ2 = 3.00, df = 8 P = 0.93, I2 = 0%
Mortality	Overall	2	2	101	3	105	0.67 (0.11, 4.24) Z = 0.43, P = 0.67	L = C	χ2 = 0.19, df = 1 P = 0.66, I2 = 0%

L: Laparoscopy-assisted distal gastrectomy; C: Conventional open distal gastrectomy; OR: Odds ratio; CI: Confidence intervals; RCTs: Randomized controlled trials; df: Degree of freedom.

Table 4 Clinical course after operation

Outcome	Type of studies includedin the meta-analysis	Trials(n)	Patients(n)	Pooled resultsWMD (95% CI)	Interpretation	Test forheterogeneity
Bowel function recovery	RCTs	3	103	-0.68 (-1.26, -0.09) Z = 2.27, P = 0.02	L < C	χ2 = 7.55, df = 2 P = 0.02, I2 = 73.5%
	Overall	12	1296	-0.68 (-0.85, -0.50) Z = 7.63, P < 0.001	L < C	χ2 = 39.6, df = 11 P < 0.001, I2 = 72.2%
Frequency of analgesic requirement	RCTs	3	103	-1.69 (-2.18, -1.21) Z = 6.82, P < 0.001	L < C	χ2 = 0.12, df = 2 P = 0.94, I2 = 0%
	Overall	6	394	-1.36 (-2.44, -0.28) Z = 2.48, P = 0.01	L < C	χ2 = 40.6, df = 5 P < 0.001, I2 = 87.7%
No. of days with temperatures more than 37°C	Overall	5	292	-1.25 (-1.69, -0.82) Z = 5.64, P < 0.001	L < C	χ2 = 2.05, df = 4 P = 0.73, I2 = 0%
Duration of hospital stay	RCTs	4	162	-3.32 (-7.69, 1.05) Z = 1.49, P = 0.14	L = C	χ2 = 33.5, df = 3 P < 0.001, I2 = 91.1%
	Overall	15	1531	-5.51 (-7.61, -3.42) Z = 5.16, P < 0.001	L < C	χ2 = 280.7, df = 14 P < 0.001, I2 = 95.0%
WBC (POD 1)	Overall	7	466	-1409.5 (-1934.6, -884.4) Z = 5.26, P < 0.001	L < C	χ2 = 5.63 , df = 6 P = 0.47, I2 = 0%
WBC (POD 3)	Overall	5	346	-1028.1 (-1578.7, -477.4) Z = 3.66, P < 0.001	L < C	χ2 = 4.18, df = 4 P = 0.38, I2 = 4.2%
WBC (POD 7)	Overall	4	319	-280.1 (-751.7, 191.5) Z = 1.16, P = 0.24	L = C	χ2 = 1.73, df = 3 P = 0.63, I2 = 0%
CRP (POD 1)	Overall	5	267	-1.33 (-2.20, -0.46) Z = 3.01, P = 0.003	L < C	χ2 = 7.24, df = 4 P = 0.12, I2 = 44.8%
CRP (POD 3)	Overall	4	199	-3.71 (-6.61, -0.80) Z = 2.50, P = 0.01	L < C	χ2 = 24.4, df = 3 P < 0.001, I2 = 87.7%
CRP (POD 7)	Overall	3	172	-1.33 (-2.90, 0.25) Z = 1.65, P = 0.10	L = C	χ2 = 8.36, df = 2 P = 0.02, I2 = 76.1%

L: Laparoscopy-assisted distal gastrectomy; C: Conventional open distal gastrectomy; RCTs: Randomized controlled trials; CRP: C-reactive protein; POD: Postoperative day; WMD: Weighted mean difference; CI: Confidence intervals; df: Degree of freedom.