. 2021 Feb 15;13(2):131–146. doi: 10.4251/wjgo.v13.i2.131

Table 2.

Baseline characteristics of included studies (age threshold 75 Years)

Variable	Young		Old		Studies		P value
No. (% of total)	4195	84.1%	796	15.9%	8
	n	%	n	%	n	%
Gender							< 0.001
Male	3572	85.1	623	78.3
Female	520	12.4	132	16.6
Unknown	103	2.5	41	5.2	1	12.5
Charlson comorbidity index							0.058
0	202	4.8	38	4.8
1	90	2.1	28	3.5
2	65	1.5	23	2.9
3	0	0.0	0	0.0
4	0	0.0	0	0.0
5	0	0.0	0	0.0
Unknown	3838	91.5	707	88.8	7	87.5
Respiratory comorbidity							0.272
Yes	43	1.0	8	1.0
No	361	8.6	104	13.1
Unknown	3791	90.4	684	85.9	6	75.0
Cardiac/Cardiovascular comorbidity							0.244
Yes	88	2.1	28	3.5
No	316	7.5	84	10.6
Unknown	3791	90.4	684	85.9	6	75.0
Diabetes mellitus							0.005
Yes	17	0.4	10	1.3
No	316	7.5	60	7.5
Unknown	3862	92.1	726	91.2	6	75.0
Renal insufficiency							0.258
Yes	1	0.0	2	0.3
No	99	2.4	48	6.0
Unknown	4095	97.6	746	93.7	7	87.5
Liver cirrhosis							-
Yes	0	0.0	0	0.0
No	0	0.0	0	0.0
Unknown	4195	100.0	796	100.0	8	100.0
ASA							< 0.001
I	164	3.9	13	1.6
II	598	14.3	117	14.7
III	194	4.6	66	8.3
IV	6	0.1	0	0.0
V	0	0.0	0	0.0
Unknown	3233	77.1	600	75.4	5	62.5
Tumor location in the esophagus							0.239
Cervical esophagus	0	0.0	0	0.0
Upper third	25	0.7	4	0.5
Middle third	253	6.6	71	8.9
Lower third	79	2.1	14	1.8
Junction	0	0.0	0	0.0
Cardia	0	0.0	0	0.0
Unknown	0	0.0	0	0.0
Unknown¹	3838	100.0	707	88.8	7	87.5
Histological type							0.022
Adenocarcinoma	2956	70.5	597	75.0
Squamous cell carcinoma	442	10.5	89	11.2
Other	21	0.5	0	0.0
Unknown¹	1	0.0	2	0.3
Unknown	775	18.5	108	13.6	2	25.0
cTNM							0.039
0	56	1.3	4	0.5
I	234	5.6	40	5.0
II	525	12.5	94	11.8
III	547	13.0	83	10.4
IV	131	3.1	14	1.8
Unknown¹	70	1.7	3	0.4
Unknown	2632	62.7	558	70.1	4	50.0
pTNM							0.648
0	1	0.0	0	0.0
I	36	0.9	21	2.6
II	20	0.5	9	1.1
III	36	0.9	19	2.4
IV	7	0.2	1	0.1
Unknown¹	0	0.0	0	0.0
Unknown	4095	97.6	746	93.7	7	87.5
Complete pathological response							0.793
Yes	60	1.4	16	2.0
No	297	7.1	73	9.2
Unknown	3838	91.5	707	88.8	7	87.5
Neoadjuvant therapy							< 0.001
Yes	714	17.0	120	15.1
No	527	12.6	146	18.3
Unknown	2954	70.4	530	66.6	3	37.5
Resection type							-
Transthoracic	590	14.1	109	13.7
Transhiatal	0	0.0	0	0.0
Unknown	3605	85.9	687	86.3	6	75.0
Surgical technique							0.046
Ivor lewis	472	11.3	98	12.3
McKeown	17	0.4	1	0.1
Orringer	0	0.0	0	0.0
Other	101	2.4	10	1.3
Unknown	3605	85.9	687	86.3	6	75.0
Surgical approach							< 0.001
Open	705	16.8	116	14.6
Minimally invasive	525	12.5	129	16.2
Hybrid	11	0.3	21	2.6
Unknown	2954	70.4	530	66.6	3	37.5

Unknown: as stated in the included study. Only studies using an age threshold of 75 years to determine older patients are shown here. Regarding clinical and pathological tumor node metastasis stage, no particular tumor node metastasis edition was used.