Table 1

Summary of basic characteristics of selected studies for meta-analysis

Ref #	First author (year)	Comparison groups	Number of patients	Age (year)	Male (%)	Type of abdominal malignancy	Nutritional goal	Nutritional goal and duration
24	Li (2015)	EEN group	136	67.7	66%	Gastric cancer	30 kcal/kg/day	With gradual increase 3–5 days after anal exhaust
24	Li (2015)	PN group	136	67.7	66%	Gastric cancer	30 kcal/kg/day	With gradual increase 3–5 days after anal exhaust
25	Boelens (2014)	EEN group	61	64	67%	Primary or recurrent rectal carcinoma	5187.5 calories/5 days	With gradual increase from 500 mL from 2 L/day
25	Boelens (2014)	EPN group	62	65	69%	Primary or recurrent rectal carcinoma	6814.1 calories/5 days	With gradual increase from 500 mL from 2 L/day
26	Liu (2013)	TEN group	40	65.8	70%	Gastric cancer	25 kcal/kg/day	3–4 days
26	Liu (2013)	TPN group	40	64.6	60%	Gastric cancer	1920 mL nutritional fluid per day;	usually 7–10 days before proceeding to a semi-liquid diet
27	Park (2012)	EEN group	18	62.7	39%	Pancreatic carcinoma, Periampullary cancer	25 kcal/kg/day;	EN or TPN infusion continued until oral intake reached 800 kcal/day
27	Park (2012)	PN group	20	61.3	60%	Pancreatic carcinoma, Periampullary cancer	25 kcal/kg/day;
28	Kim (2011)	EEN group	17	60	71%	NA	Total daily calories: 25 kcal/kg/day Total daily protein: 1.5 g/kg/day	Total of 5 days (EN+partial parenteral nutrition given for the first 3 days)
28	Kim (2011)	TPN group	16	64.5	81%	NA		TPN was initiated on the first postoperative day, and discontinued until POD 5
4	Liu (2011)	EN group	28	59.7	57%	NA	Calories: 27 kcal/kg/day; Nitrogen: 0.2 g/kg/day	50% daily value at POD1, full volume from POD2 to POD6
4	Liu (2011)	TPN group	30	60.5	57%	NA	Calories: 27 kcal/kg/day; Nitrogen: 0.2 g/kg/day	50% daily value at POD1, full volume from POD2 to POD6
29	Dong (2010)	EN group	19	61.7	84%	Gastric cancer	20–25 kcal/kg/day	Continued until POD 7
29	Dong (2010)	PN group	19	60.2	84%	Gastric cancer	20–25 kcal/kg/day	Continued until POD 7
30	Klek (2008)	SEN group	53	61.4	74%	Gastrointestinal cancer	Starting at 25 mL/h (1.25 kcal/mL), with 25 mL increase daily until 100 mL/h	Continued until POD 7
		IMEN group	52	61.2	65%			Continued until POD 7
		SPN group	49	60	71%		Protein: 0.15 g N/kg Energy: 150 kcal/day Supplements PRN	Continued until POD 7
		IMPN group	51	61.4	71%		Protein: 0.15 g N/kg Energy: 150 kcal/day Supplements PRN	Continued until POD 7
31	Wu (2007)	EN group	215	61.7	55%	Gastrointestinal cancer	28 kcal/kg/day	Continued until POD 7; gradual transition to normal diet
31	Wu (2007)	PN group	215	62.3	57%	Gastrointestinal cancer	30 kcal/kg/day	Continued until POD 7; gradual transition to normal diet
32	Alivizatos (2005)	EIN group	15			Gastric, pancreatic, hepatocellular, or colon carcinoma	25 kcal/kg/day	Continued at least 5 days or until normal diet possible (oral diet ≧1000 kcal/day)
32	Alivizatos (2005)	Glu-TPN group	14			Gastric, pancreatic, hepatocellular, or colon carcinoma	25 kcal/kg/day
33	Ates (2004)	EEN group	22	58.3	82%	Gastric cancer, colorectal cancer	Non-protein calorie: 35 kcal/kg/day; Nitrogen: 0.26 g/kg/day; Carbohydrate/lipid ratio: 5	Initiated 5 days prior to surgery and continued until POD 7. EEN group received partial parenteral nutrition from POD 1–4 (after reaching nutritional goal: 2 mL/kg/h).
33	Ates (2004)	TPN group	20	60.1	80%	Gastric cancer, colorectal cancer
19	Bozzetti (2001)	EN group	159	64.8	59%	Stomach/esophagus cancer, hepatobiliary cancer	Total calorie: 26.75 kcal/kg/day; Nitrogen: 1.4 g amino acid/kg/day	Gradual increase of infusion rate to full regimen from POD1–4, continued until end of treatment (oral intake of 3350 kJ/day)
19	Bozzetti (2001)	PN group	158	64.1	58%	Stomach/esophagus cancer, hepatobiliary cancer
34	Braga (2001)	EEN group	126	64.1	54%	Gastric cancer, pancreatic cancer, esophageal cancer	25 kcal/kg/day	Gradual increase to full regimen on POD4, then continue until oral intake of 800 kcal/day
34	Braga (2001)	TPN group	131	62.9	54%	Gastric cancer, pancreatic cancer, esophageal cancer	25 kcal/kg/day
35	Pacelli (2001)	EN group	119	61.5	61%	Gastric, colorectal, pancreatic, and cholangiocarcinoma, other GI cancers	Nonprotein: 25 kcal/kg/day Nitrogen: 0.2 g/kg/day	EN+TPN for POD 1–3; EN continued until oral intake of ≧1000 mL fluids/day
35	Pacelli (2001)	TPN group	122	61.6	59%		Nonprotein: 25 kcal/kg/day Nitrogen: 0.2 g/kg/day	continued until oral intake of ≧1000 mL fluids/day
36	Braga (1998)	Enriched group	55	60.9	NA	NA	NA	NA
36	Braga (1998)	TPN group	56	61.7	NA	NA	NA	NA
37	Gianotti (1997)	EN group	87	64.5	55%	Pancreatic and gastric cancer	25 kcal/kg per day	EN+TPN for POD 1–3 to reach nutritional goal; EN only until POD 7; Oral intake begins POD8
37	Gianotti (1997)	PN group	86	63.8	54%	Pancreatic and gastric cancer	25 kcal/kg per day	NA
38	Braga (1996)	EEN group	20	59	60%	Gastric cancer, pancreatic cancer	Calorie: 25 kcal/kg/day Protein: 0.25 g N/kg/day	EN+TPN for POD 1–4; EN continued until POD 8
38	Braga (1996)	TPN group	20	60	60%	Gastric cancer, pancreatic cancer	Calorie: 25 kcal/kg/day Protein: 0.25 g N/kg/day	NA
39	Braga (1995)	Enriched group	26	59.3	NA	Gastric cancer, pancreatic cancer	25 kcal/kg/day 0.25 g of N/kg/day	EN+TPN for POD 1–4; EN continued until POD 8
39	Braga (1995)	Parenteral group	27	59.8	NA	Gastric cancer, pancreatic cancer	25 kcal/kg/day 0.25 g of N/kg/day

EEN, early enteral nutrition; EN; enteral nutrition; EPN, early parenteral nutrition; IMEN, immunostimulating enteral nutrition; IMPN, immunostimulating parenteral nutrition; N, nitrogen; NA, not applicable; PN, parenteral nutrition; POD, postoperative day; PRN, pro re nata (as needed); SEN standard enteral nutrition; SPN, standard parenteral nutrition; TEN, total; enteral nutrition; TPN, total parenteral nutrition.