Characteristics of the patients
The baseline characteristics of the patients are shown in Table 1, Table 2 and Table 3. There were 196 (78.7%) males and 53 (21.3%) females in the population. The median age of all enrolled patients was 64 years, ranging from 31-82 years. The details of the pathological outcomes showed that most patients (72.3%) had pure adenocarcinoma, and the remaining patients had mixed adenocarcinoma with signet ring or mucinous tumors. There were 165 (66.3%) patients with tumor diameters larger than 4 cm and 84 (33.7%) patients with tumor diameters less than or equal to 4 cm. Among them, 127 (51.0%) patients had lymphovascular invasion, and 154 (61.8%) patients had perineural invasion. Pathological differentiation showed that only 2 patients were classified as G1, 92 (36.9%) were classified as G2, and 155 (62.2%) were classified as G3.
Table 1 Clinical characteristics of 249 patients
Characteristics
|
Case No. (%)
|
Gender
|
|
Male
|
196 (78.7)
|
Female
|
53 (21.3)
|
Age
|
|
Range
|
31-82
|
Median
|
64
|
Table 2 Surgery characteristics of 249 patients
Characteristics
|
Case No. (%)
|
Type of gastric resection
Total gastrectomy
Proximal gastrectomy
Surgical approach
Left thoracotomy
Ivor Lewis
Transhiatal
Intraoperative blood transfusion
Yes
No
|
115 (46.2)
134 (53.8)
73 (29.3)
1(0.4)
175 (70.3)
231 (92.8)
18 (7.2)
|
Table 3 Pathology and postoperative characteristics of 249 patients
Characteristics
|
Case No. (%)
|
Type of pathology
|
|
Adenocarcinoma
|
180 (72.3)
|
Adenocarcinoma with partial signet
ring or mucinous
|
69 (27.7)
|
Tumor size
>4 cm
≤4 cm
N stage
N0
N1
N2
N3
pTNM stage
|
165 (66.3)
84 (33.7)
71(28.5)
42(16.9)
49(19.7)
87(34.9)
|
I
II
III
IV
Differentiation
G1
G2
G3
Lymphovascular invasion
Yes
No
Perineuronal invasion
Yes
No
Adjuvant chemotherapy
Yes
No
Number of metastatic lymph nodes
Median (range)
PNLNR
>1
=0
≤ 1
Postoperative hospital stays
>10 d
≤ 10 d
|
23 (9.2)
45 (18.1)
94 (37.8)
87 (34.9)
2 (0.8)
92 (36.9)
155 (62.2)
127 (51)
122 (49)
154 (61.8)
95 (38.2)
100 (40.2)
149 (59.8)
3 (0-38)
32 (12.9)
70 (28.1)
147 (59)
133 (53.4)
116 (46.6)
|
PNLNR; positive lymph nodes/ negative lymph nodes rate
Among the patients who underwent lymph node dissection, 70 (28.1%) patients had no positive lymph nodes, 32 (12.9%) patients had a PNLNR greater than 1, and 147 (59.0%) had a PNLNR less than 1. According to TNM staging, 23 (9.2%) patients were defined as stage I, 45 (18.1%) as stage II, 94 (37.8%) as stage III and 87 (34.9%) as stage IV.
In terms of surgery, there were a total of 3 types of surgical approaches, including 73 (29.3%) cases of left thoracotomy, 1 (0.4%) case of Ivor-Lewis surgery, and 175 (70.3%) cases of transhiatal surgery. Because only one patient underwent Ivor-Lewis surgery, we excluded this patient in the univariate and multivariate analyses. Total gastrectomy was performed in 115 (46.2%) patients, and proximal gastrectomy was performed in 134 (53.8%) patients. During surgery, a small portion of patients (n=18) received intraoperative blood transfusions. After surgery, 53.4% patients stayed in the hospital for longer than 10 days, and 46.6% patients stayed for less than or equal to 10 days. Long hospital stays were mainly due to postoperative complications, postoperative nutritional status and several other reasons. Regarding adjuvant chemotherapy, 100 (40.2%) patients received adjuvant chemotherapy, and the main chemotherapy regimens were SOX (S-1 and oxaliplatin) and XELOX (capecitabine and oxaliplatin).
Survival data and prognostic factors
We conducted our last follow-up in October 2019 by telephone interview or outpatient or inpatient department visits. The median follow-up time was approximately 75 months. At the last follow-up, 111 (44.6%) patients were still alive. The 1-year, 3-year and 5-year survival rates of all enrolled patients were 72%, 59%, and 49%, respectively. The median survival time (mOS) of these patients was 70.1 m (95% CI 53.6-86.6 m). Female patients had a significantly longer survival time than male patients (NA vs. 62.4 m, P=0.039). Patients with pure adenocarcinoma had a significantly longer survival time than mixed pathology patients (85.4 vs. 42.5 m, P=0.011). Patients with perineural invasion (NA vs. 48.1, P<0.001) or lymphovascular invasion (NA vs. 40.9, P<0.001) had shorter survival times, received fewer blood transfusions (12.4 vs. 81.8, P<0.001) had a shorter survival time (Figure 1). Patients who received adjuvant chemotherapy (61.7 vs. 93.4, P=0.027) had a longer survival time. The median survival time of patients without lymph node metastasis was not reached, while the median survival time of N2 and N3 patients was 64.5 m and 24.0 m, respectively. Regarding the PNLNR, the mOS of patients with a PNLNR≤ 1 was 67.2 m and that of patients with a PNLNR>1 was 11.8 m (Figure 2). The mOS of patients with a tumor size greater than 4 cm was also not reached, while the mOS of those with a tumor size less than or equal to 4 cm was 43.8 m (Figure 3). pTNM stage was also significantly related to survival time. Patients with elevated CA199, CEA, CA242 and AFP levels had shorter survival times (Table 4). Only 1 of 249 patients died within 30 days after surgery.
Table4 Univariate analysis of survival after surgery
Variables
|
MST (month)
|
Univariate analysis
|
P-value
|
|
|
HR
|
95% CI
|
|
Gender (male vs. female)
|
62.4 vs. NA
|
1.608
|
1.019-2.539
|
0.039
|
Pathology (adeno vs. mix)
Blood transfusion (no vs. yes)
Surgical approaches (left thoracotomy vs. transhiatal)
Tumor size (≤4cm vs. >4cm)
Adjuvant chemotherapy (no vs. yes)
Postoperative hospital stays (≤10d vs. >10d)
Type of gastric resection (total vs. proximal)
PNLNR
=0
≤ 1
>1
Perineuronal invasion (no vs. yes)
Lymphovascular invasion (no vs. yes)
Differentiation
pTNM stage
I
II
III
IV
Serum CA199 (U/ml) (<37 vs. ≥37
)
Serum CEA (ng/ml) (<5 vs. ≥5
)
Serum CA242 (U/ml) (<20 vs. ≥20
)
Serum CA125 (U/ml) (<35 vs. ≥35
)
Serum AFP (ng/ml) (<10 vs. ≥10
)
Serum CA724 (U/ml) (<6.9 vs. ≥6.9
)
Serum ferritin (ng/ml) (<274.66 vs. ≥274.66
)
|
85.4 vs. 42.5
12.4 vs. 81.8
42.5 vs. 87.6
NA vs. 43.8
61.7 vs. 93.4
59.9 vs. 99.7
73.5 vs. 64.5
NA
67.2
11.8
NA vs. 48.1
NA vs. 40.9
80 vs. 73 vs. 63
97.4
99.7
119.56
24.5
93.4 vs. 31.7
80.0 vs. 26.3
73.0 vs. 12.0
71.4 vs. 70.1
80.3 vs. 51.1
70.1 vs. 80.0
|
0.632
0.262
1.569
0.410
1.477
0.806
0.960
0.403
0.772
1
0.454
0.448
0.253
0.265
0.364
1
0.784
0.740
0.746
0.605
1.067
0.862
0.952
|
0.442-0.903
0.156-0.440
1.110-2.218
0.274-0.616
1.042-2.094
0.680-0.956
0.811-1.135
0.298-0.543
0.613-0.972
1
0.310-0.664
0.317-0.634
0.121-0.526
0.155-0.451
0.248-0.533
1
0.654-0.939
0.623-0.878
0.596-0.934
0.423-0.866
0.761-1.496
0.715-1.039
0.708-1.280
|
0.011
<0.001
<0.001
<0.001
0.027
0.012
0.630
<0.001
<0.001
<0.001
0.851
<0.001
0.008
<0.001
0.010
0.004
0.706
0.117
0.745
|
The prognostic factors included age, sex, pathological type, tumor size, type of surgical approach, serum tumor biomarkers, and blood transfusion. Both univariate and multivariate analyses were applied (Table 4 and Table 5). Among the factors related to survival in univariate analyses, 16 factors had significance, including sex, pathological type, intraoperative blood transfusion, surgical approach, and several serum tumor biomarkers. Factors including type of gastric resection, tumor differentiation, elevated serum AFP and serum ferritin had no significance. Then, multivariate analysis was conducted to identify the predictive indicators for a good prognosis using the parameters with a P value less than 0.5 in univariate analysis. Multivariate analysis showed that intraoperative blood transfusion, tumor size larger than 4 cm, no adjuvant chemotherapy, higher positive/negative lymph node ratio, perineural invasion, elevated serum CEA before surgery, and length of stay in the hospital greater than 10 days after surgery were independent risk factors for survival in resected Siewert type II AEG patients.