Stomach cancer surgery

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Parminder Dhingra, M.D. [2] Mohammed Abdelwahed M.D[3]

Surgery is the mainstay of treatment for stomach cancer. Endoscopic resection is suggested for early gastric cancer. There are criteria for endoscopic resection of ealry gastric cancer. Methods for endoscopic resection include endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Side effects of endoscopy includes bleeding and perforation. For T1 tumors, a 2cm macroscopic resection of tumor margin should be performed. Proximal margin of at least 3 cm is recommended for T2 or deeper tumors with an expansive growth pattern and 5 cm for those with an infiltrative growth pattern. For tumors invading the esophagus, a 5-cm margin is not necessarily required, but frozen section examination of the resection line is desirable to ensure a R0 resection. There is a debate about optimal lymph node removal. D1 lymphadenectomy refers to a dissection of only the perigastric lymph nodes. D2 lymphadenectomy is an extended lymph node dissection, includes removal of nodes along the hepatic, left gastric, celiac, and splenic arteries, as well as those in the splenic hilum. D3 dissection is a super-extended lymphadenectomy. The surgery includes D2 lymphadenectomy plus the removal of nodes within the porta hepatis and periaortic regions.

• Early gastric cancer is an invasive gastric cancer that invades no more than the submucosa whatever the lymph node metastasis condition (T1 and any N)
• Endoscopic resection is suggested for:
  • Patients without suspected lymph node involvement
  • Tumor size <20 mm in diameter
  • Differentiated intestinal histology
• In most trials, there are no differences in outcome between the surgical and the endoscopic treatment.^[1]

The standard criteria for lesions qualifying for endoscopic resection are the following:^[2][3]

1) Confined to the mucosa

2) Smaller than 2 cm for superficially elevated type lesions

3) Smaller than 1 cm for the flat and depressed type lesions

4) No ulcer or ulcer scar

5) No venous or lymphatic involvement

Expansion of the criteria to involve more tumors eligible for endoscopic resection was suggested by Japanese centers and these criteria include:^[4]

• Differentiated type without ulceration, and mucosal tumors of any size
• Differentiated type, with ulceration, and mucosal tumors less than 30 mm
• Undifferentiated type, without ulceration, and mucosal tumors 20 mm in size or smaller

The following are the different types of endoscopic resection techniques for gastric cancer:^[5]

• Endoscopic mucosal resection (EMR):
  • The lesion and the surrounding mucosa are lifted by submucosal injection of saline and removed using a steel snare.

• Endoscopic submucosal dissection (ESD):
  • The mucosa surrounding the lesion is incised using a high-frequency electric knife.
  • ESD is more likely to result in complete resection of early gastric cancer but requires more time and endoscopic skills.

• Bleeding^[6]
• A tumor size of more than 4 cm is a risk factor for acute bleeding
• Antithrombotic drug therapy is a risk factor for delayed bleeding
• Bleeding treatment is injection therapy, electrocoagulation, ligation with a detectable snare, and endoscopic clipping.

• Perforation rate for ESD is 4.5 percent, compared with 1.0 percent for EMR.^[7]
• Tumor location in the upper stomach and size more than 2 cm have been associated with an increased risk of perforation with ESD.
• Treatment of a perforation is endoscopic clipping, open or laparoscopic surgery in case of failed clipping.

The following criteria need to be fulfilled to consider endoscopic resection curative:^[8]

• Enbloc resection
• Tumor size < 2 cm
• Histologically of differentiated type
• Staging of tumor < T1a
• Negative horizontal margin
• Negative vertical margin
• No lymphatic or vascular infiltration

Any resection that does not satisfy any of the above criteria is considered non-curative.

• There is no standard approach for managing patients with non-curative resection. Gastrectomy has been recommended especially for tumors associated with a higher risk for lymph node metastases.
• Gastrectomy with removal of perigastric lymph nodes is recommended.^[9]
• Seven percent of patients who had gastrectomy and lymph node dissection after non-curative endoscopic resection for early gastric cancer had lymph node metastasis after the procedure.

• Patients with only positive lateral margins can be managed with endoscopic therapy rather than surgery.
• Almost 90 percent of lateral postitve margins were followed endoscopically with no recurrences.
• Patients with positive vertical margins, submucosal invasion, or lymphovascular invasion, are treated by surgery.

Local mucosal recurrence after EMR/ESD for tumors that had fulfilled the criteria for indication for endoscopic resection may be treated by another ESD.^[11]

• Annual endoscopy with abdominal ultrasonography or CT scan follow-up is recommended.
• Helicobacter pylori should be tested and treated if found.

• Surgical treatment should be performed after non-curative resection such as endoscopic coagulation using a laser or argon-plasma coagulator.

Surgical management of a gastric tumor with resection of adjacent lymph nodes presents the best chance for long-term survival.

• Standard gastrectomy: In the standard gastrectomy, two-thirds of the stomach is resected. It is the principal surgical procedure used.
• Non-standard gastrectomy: In non-standard gastrectomy, the extent of gastric resection and lymphadenectomy is altered according to the stage of tumor.

• Modified surgery: The extent of gastric resection and lymphadenectomy is reduced if compared to standard surgery.

• Extended surgery

• Gastrectomy with resection of adjacent involved organs

• Gastrectomy with extended lymphadenectomy

• Palliative surgery: Palliative gastrectomy or gastrojejunostomy is selected depending on the resectability of the primary tumor and surgical risks to relieve symptoms such as bleeding or obstruction.
• Reduction surgery: Reduction surgery aim is to prolong survival by reducing tumor volume.

• Total gastrectomy: Total resection of the stomach including the cardia and pylorus
• Distal gastrectomy: Stomach resection including the pylorus. The cardia is preserved
• Pylorus-preserving gastrectomy: Stomach resection preserving the upper third of the stomach and the pylorus with a portion of the antrum
• Proximal gastrectomy: Stomach resection including the cardia. The pylorus is preserved
• Segmental gastrectomy: Circumferential resection of the stomach preserving the cardia and pylorus
• Local resection
• Non-resectional surgery (bypass surgery, gastrostomy, and jejunostomy)

• For T1 tumors, a gross resection margin of 2 cm should be obtained.
• Proximal margin of at least 3 cm is recommended for T2 or deeper tumors with an expansive growth pattern and 5 cm for those with an infiltrative growth pattern.
• For tumors invading the esophagus, a 5-cm margin is not necessarily required, but frozen section examination of the resection line is desirable to ensure a R0 resection.
• When the tumor border is unclear, preoperative endoscopic marking by clips of the tumor border based on biopsy results will be helpful for decision making regarding the resection line.

• The standard surgical procedure is total or distal gastrectomy.
• Pancreaticosplenectomy
  • Pancreatic invasion by tumor requires total gastrectomy regardless of the tumor location.
• Total gastrectomy with splenectomy
  • It should be considered for tumors that are located along the greater curvature with metastasis to no. 4 lymph nodes.
• Esophagectomy and proximal gastrectomy
  • It should be considered for adenocarcinoma located on the proximal side of the esophagogastric junction.
• Pylorus-preserving gastrectomy
  • For tumors in the middle portion of the stomach with the distal tumor border at least 4 cm proximal to the pylorus.

• Vagal nerve preservation
  • It is reported that preservation of the hepatic branch of the anterior vagus and the celiac branch of the posterior vagus contributes to improving postoperative quality of life through reducing post-gastrectomy gallstone formation, diarrhea and weight loss. In case of PPG, the hepatic branch should be preserved to maintain the pyloric function.
• Omentectomy
  • Removal of the greater omentum is usually integrated into the standard gastrectomy for T3 or deeper tumors.

For T1/T2 tumors, the omentum more than 3 cm away from the gastroepiploic arcade may be preserved.

• Bursectomy^[14]
  • Bursectomy is removal of the inner peritoneal surface of the bursa omentalis.
  • It should be avoided in T1/T2 tumors to prevent injury to the pancreas and adjacent blood vessels.
  • There are some survival benefits for bursectomy in T3/T4a tumors.

• One of the most controversial areas in the surgical management of gastric cancer is the optimal extent of lymph node dissection.^[15]
• The draining lymph nodes for the stomach have been meticulously divided into 16 stations by Japanese surgeons; stations 1 to 6 are perigastric, and the remaining 10 are located adjacent to major vessels, behind the pancreas, and along the aorta.^[16]

D1 lymphadenectomy

• It refers to a dissection of only the perigastric lymph nodes.
• A D1 lymphadenectomy is indicated for T1a tumors that do not meet the criteria for EMR/ ESD and for T1bN0 tumors that are histologically of differentiated type and 1.5 cm or smaller in diameter.

D2 lymphadenectomy

• It is an extended lymph node dissection, includes removal of nodes along the hepatic, left gastric, celiac, and splenic arteries, as well as those in the splenic hilum.
• It is indicated for potentially curable T2-T4 tumors.
• A D2 lymphadenectomy should be performed whenever nodal involvement is suspected.

D3 dissection

• It is a superextended lymphadenectomy. The surgery includes D2 lymphadenectomy plus the removal of nodes within the porta hepatis and periaortic regions.^[17]

• Therapeutic options to control symptoms of local disease progression, such as nausea, pain, bleeding, and obstruction, include palliative surgical resection, surgical bypass (gastrojejunostomy), radiation therapy (RT), and endoscopic techniques.

• Palliative resection
  • Palliative gastrectomy should be reserved for extreme, highly symptomatic cases where less invasive methods cannot be used.^[18]
  • Two-year survival for chemotherapy alone versus gastrectomy plus chemotherapy was 32 versus 25 percent.
  • Patients undergoing gastrectomy had a significantly higher incidence of several serious adverse events related to chemotherapy, including leucopenia, nausea, anorexia, and hyponatremia.

• Gastrojejunostomy
  • Palliative gastrojejunostomy for gastric outlet obstruction associated with unresectable advanced gastric cancer can improve food intake.^[19]
  • Palliative gastrojejunostomy for patients with metastatic gastric cancer is reserved for cases where less invasive methods cannot be used.

• Endoscopic stent placement^[20][21]
  • For palliation of obstructive symptoms, endoscopic placement of a stent provides a less invasive alternative to surgery for symptom palliation and may possibly be more effective in symptom relief.
  • Stenting may achieve a better quality of life compared with other forms of palliation.
  • In a review of two randomized trials of endoscopic stenting versus palliative gastrojejunostomy, there were no statistically significant differences between the two procedures in terms of efficacy or complications.

• Endoscopic laser therapy^[22]
  • Laser photocoagulation can be effective, particularly for large tumors with diffuse bleeding.
  • An alternative that is being used increasingly is argon plasma coagulation.

Total gastrectomy

• Roux-en-Y esophagojejunostomy^[23]
• Jejunal interposition
• Double tract method

Distal gastrectomy

• Billroth I gastroduodenostomy^[24]
• Billroth II gastrojejunostomy
• Roux-en-Y gastrojejunostomy
• Jejunal interposition

Pylorus-preserving gastrectomy^[25]

• Gastro-gastrostomy
• Proximal gastrectomy
• Esophagogastrostomy
• Jejunal interposition
• Double tract method

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