Direct gastric invasion is associated with poor prognosis in esophageal squamous cell carcinoma involving the lower-third esophagus

Table 3 Demographic and clinical characteristics of 176 patients with esophageal squamous cell carcinoma involving the lower third of the esophagus, n (%)

Variable	With gastric invasion (n = 20)	Without gastric invasion (n = 156)	P value
Age in years (mean ± SD)	58.2 ± 8.7	57.3 ± 8.3	0.65
< 57.3	10 (50.0)	75 (48.1)	0.87
≥ 57.2	10 (50.0)	81 (51.9)
Sex			0.58
Male	19 (95.0)	150 (96.2)
Female	1 (5.0)	6 (3.8)
T category			0.31
T2	1 (5.0)	23 (14.7)
T3	13 (65)	94 (60.3)
T4a	2 (10.0)	5 (3.2)
T4b	4 (20.0)	34 (21.8)
N category
N0	1 (5.0)	16 (10.3)	0.11
N1	8 (40.0)	50 (32.1)
N2	4 (20.0)	64 (41.0)
N3	7 (35.0)	26 (16.7)
M category
M0	15 (75.0)	137 (87.8)	0.16
M1	5 (25.0)	19 (12.2)
Clinical stage			0.27
I	0 (0.0)	1 (0.6)
II	2 (10.0)	16 (10.3)
III	9 (45.0)	99 (63.5)
IV	9 (45.0)	40 (25.6)
Histological grade			0.41
Grade 1, well differentiated	0 (0.0)	9 (5.8)
Grade 2, moderately differentiated	14 (70.0)	105 (67.3)
Grade 3, poorly differentiated	6 (30.0)	31 (19.9)
Missing	0 (0.0)	11 (7.1)
Tumor location			0.001
Upper to lower third of the esophagus	0 (0.0)	18 (11.5)
Middle to lower third of the esophagus	3 (15.0)	74 (47.4)
Lower third of the esophagus	17 (85.0)	64 (41.0)
Tumor length, cm (median, IQR)	7.1 (6.3-10.8)	7.1 (5.0-10.0)	0.41
Baseline renal function			> 0.99
eGFR < 60 mL/minutes	3 (15.0)	28 (17.9)
eGFR ≥ 60 mL/minutes	17 (85.0)	128 (82.1)
Serum albumin, g/dL (mean ± SD)	3.9 ± 0.5	4.0 ± 0.5	0.69
ECOG performance status			0.08
0	2 (10.0)	24 (15.4)
1	15 (75.0)	127 (81.4)
2	3 (15.0)	5 (3.2)
Treatment modality			0.24
CRT	15 (75.0)	96 (61.5)
CRT followed by surgery	5 (25.0)	60 (38.5)

CRT: Chemoradiotherapy; ECOG: Eastern Cooperative Oncology Group; eGFR: Estimated glomerular filtration rate; IQR: Interquartile range.