Oncological outcomes
In a proximal gastrectomy, the cardia and upper portions of the gastric corpus are resected; more than half of the stomach remains. The extent of an appropriate lymphadenectomy in a function-preserving gastrectomy has been defined by the Japanese guidelines; the D1 lymphadenectomy stations for a proximal gastrectomy include 1, 2, 3a, 4sa, 4sb, and 7 (Table
1, Table
2). If a D1+ lymphadenectomy is performed, stations 8a, 9, and 11p must also be removed [
4]. For tumours that affect the oesophagus, the lymphadenectomy also includes station 110 (Table
2). Due to the lower extent of the D1+ lymphadenectomy in proximal gastrectomy, the vagal branches to the liver and pylorus can be preserved.
Table 1
Numbering of lymph node stations according to the current classification of the Japanese Research Society for Gastric Cancer. Reprinted with permission from: Japanese Gastric Cancer Association, Japanese Classification of Gastric Carcinoma: 3rd English edition, Gastric Cancer (2011) 14: 101-112
1 | Right paracardial nodes |
2 | Left paracardial nodes |
3 | Nodes along the lesser curvature |
4 | Nodes along the greater curvature |
4sa: along short gastrics |
4sb: left greater curvature lymph nodes along the left gastroepiploic artery |
4d: right greater curvature lymph nodes |
5 | Suprapyloric lymph nodes |
6 | Infrapyloric lymph nodes |
7 | Nodes along the left gastric artery |
8 | Nodes along the common hepatic artery |
9 | Nodes around the celiac axis |
10 | Splenic hilar nodes |
11 | Nodes along the splenic artery |
12 | Nodes in the hepatoduodenal ligament, in the caudal half between the confluence of the right and left hepatic ducts and the upper border of the pancreas |
12a: Nodes along the proper hepatic artery |
12b: Nodes along the bile duct |
12p: Nodes along the portal vein |
13 | Lymph nodes at the posterior aspect of the pancreatic head |
14 | Lymph nodes at the root of the mesentery |
14v: Nodes along superior mesenteric vein |
14a: Nodes along superior mesenteric artery |
15 | Lymph nodes in the mesocolon of the colon transversum |
16 | Para-aortic lymph nodes |
17 | Lymph nodes on the anterior surface of the pancreatic head |
18 | Lymph nodes along the inferior border of the pancreatic body |
19 | Infradiaphragmatic lymph nodes predominantly along the subphrenic artery |
20 | Hiatal paraesophageal lymph nodes |
110 | Paraesophageal lymph nodes in the lower mediastinum |
111 | Supradiaphragmatic lymph nodes distant from the oesophagus |
112 | Posterior mediastinal lymph nodes distant from the oesophagus and the hiatus |
Table 2
Lymph node dissection in gastrectomy for gastric cancer [
4]
Total gastrectomy | D1 | No. 1–7 |
D1+ | D1 + No. 8a, 9, 11p + No. 110 for tumours invading the oesophagus |
D2 | D1 + No. 8a, 9, 11p, 11d, 12a + No. 19, 20, 110, 111 for tumours invading the oesophagus |
Distal gastrectomy | D1 | No. 1, 3, 4sb, 4d, 5, 6, 7 |
D1+ | D1 + No. 8a, 9 |
D2 | D1 + No. 8a, 9, 11p, 12a |
Pylorus-preserving gastrectomy | D1 | No. 1, 3, 4sb, 4d, 6, 7 |
D1+ | D1 + No. 8a, 9 |
Proximal gastrectomy | D1 | No. 1, 2, 3a, 4sa, 4sb, 7 |
D1+ | D1 + No. 8a, 9, 11p + No. 110 for tumours invading the oesophagus |
The concept of less extensive lymphadenectomy for proximal gastric cancer was also supported by data from patients diagnosed with more advanced tumours. A retrospective analysis of 202 patients diagnosed with T2/T3 tumours limited to the proximal stomach did not demonstrate a single lymph node metastasis in the supra- or infrapyloric lymph nodes. The lymph nodes along the right gastroepiploic artery and the proper hepatic artery were involved in < 1% of cases [
14].
There are numerous retrospective studies and meta-analyses showing no difference in the overall 5-year survival between T1 tumour patients who underwent a proximal gastrectomy and T1 tumour patients who underwent a total gastrectomy [
15‐
19]. A Japanese prospective non-randomised study and a Chinese prospective randomised study have additionally confirmed the oncological equivalence of both methods for early gastric cancer [
20,
21].
Previous literature indicates that a proximal gastrectomy with a D1+ lymphadenectomy represents an oncologically adequate operation for proximal gastric carcinomas, particularly for T1 carcinomas, without evidence of lymph node metastases. There is retrospective data that reveals significantly higher recurrence rates in cases of more advanced carcinomas [
22]. The available data may vary in usefulness due to the predominantly retrospective nature of the studies.
Functional outcomes following proximal gastrectomy
One potential benefit of the proximal gastrectomy is that nutritional status may deteriorate less compared to the total gastrectomy [
20,
23]. However, this advantage is accompanied by higher reflux rates and anastomotic stenosis [
19,
20,
24]. The exact extent of the reflux symptoms depends on which reconstruction is chosen.
There are several potential options for reconstruction after proximal gastrectomy. The commonly chosen options are oesophagogastrostomy, jejunal interposition, and double-tract reconstruction. Double-tract reconstruction has become more common in the past few years.
Oesophagogastrostomy is the simplest method and offers the advantage of a physiological reconstruction. The method has a low risk of technical failure since only one anastomosis is necessary. Another advantage is the straightforward surveillance of the gastric remnant due to the direct endoscopic access from the oesophagus. A propensity score-matched analysis showed better nutritional status after proximal gastrectomy compared to total gastrectomy, but the benefit was offset by higher rates of reflux symptoms and anastomotic stenosis [
25].
A method to improve reflux symptoms after a proximal gastrectomy is to form a tube from the residual stomach. A Chinese prospective cohort study, which included 66 consecutive patients, indicated that the formation of a gastric tube led to a reduction in reflux symptoms and in endoscopically confirmed reflux esophagitis [
26].
In addition to gastric tube reconstruction, anti-reflux procedures that can be used in addition to oesophagogastrostomy have been developed. The double-flap reconstruction is an anti-reflux measure that is frequently implemented in Asian countries. During the double-flap reconstruction, an H-shaped seromuscular flap is formed from the anterior wall of the residual stomach, which is placed around the oesophagogastrostomy after suturing the anastomosis [
27]. Retrospective studies and a recent meta-analysis highlighted an improvement in reflux oesophagitis rates, which decreased from an average of 19 to 9% by adding the double-flap reconstruction to the oesophagogastrostomy [
24,
28,
29].
Another measure to minimise postoperative reflux is the side overlap oesophagogastrostomy with fundoplication by Yamashita (SOFY) method; the initial results from this method were presented in 2017 [
30]. In this procedure, a linear stapler is used to create a slit-shaped anastomosis between the right side of the oesophagus and the anterior wall of the residual stomach. The oesophagus, stomach and diaphragm are then fixed against each other with sutures. This construction serves as a backflow prevention mechanism and has been modified since its introduction [
30]. Preliminary results revealed reflux rates of 2.8% when applying the modified SOFY method [
31]. However, studies with high case numbers are not available for this method.
Another strategy to avoid postoperative reflux is the creation of an oesophagojejunostomy. Jejunal interposition, jejunal pouch interposition and double-tract reconstruction are procedures that can be used for this purpose.
Jejunal interposition consists of an 8–15 cm long pedicled loop of proximal jejunum being interposed between the oesophagus and the gastric remnant. The jejunal interposition serves as a substitute for the gastroesophageal junction by preventing reflux [
32]. When compared to oesophagogastrostomy, a meta-analysis of six studies demonstrated that jejunal interposition has the disadvantages of inconvenient operating time, intraoperative blood loss and a longer hospital stay. These effects demonstrate the relatively more convenient reconstruction in oesophagogastrostomy. However, there was a trend towards better reflux control in the jejunal interposition group [
33].
An additional retrospective study with 301 patients examined the functional outcome after jejunal interposition compared to reconstruction with a gastric tube. Although the operation time for jejunal interposition is longer, there were fewer cases of reflux esophagitis and fewer post-gastrectomy syndromes [
34].
However, residual food is a prevalent issue in jejunal interposition. It becomes even more prevalent when a jejunal pouch is used [
24].
To overcome the high technical requirements for jejunal interposition, double-tract reconstruction was developed. When laparoscopic techniques are used, double-tract reconstruction is less prone to technical failure. During double-tract reconstruction, the jejunum is divided approximately 15-cm distal from the ligament of Treitz. The distal limb is anastomosed to the oesophagus. A side-to-side jejunogastrostomy is performed 15 cm below the oesophagojejunostomy. A jejunogastrostomy is performed approximately 40 cm below the oesophagojejunostomy. A meta-analysis of seven retrospective studies comparing double-tract reconstruction to total gastrectomy demonstrated that double-tract reconstruction is superior in maintaining adequate B12 levels. This superior effect does not come at the expense of reflux or anastomotic strictures [
35]. In addition, an analysis of the postoperative outcomes of nine studies revealed low rates of reflux oesophagitis (9.6%) following double-tract reconstruction. In that study, remnants of food also caused an issue in the reconstruction [
24]. The Korean KLASS05 study randomised laparoscopic proximal gastrectomy with double-tract reconstruction versus laparoscopic total gastrectomy. The short-term results of this study indicate no disadvantage of a proximal resection in terms of perioperative morbidity [
36]. The long-term results regarding the nutritional status and the oncological outcomes are still pending.