Perioperative management - Laparoscopic total gastrectomy with D2 lymphadenectomy

Surgical therapy is the only curative option and standard treatment for all potentially resectable gastric carcinomas. It generally consists of radical resection of the primary tumor with clear margins (R0 resection in all planes: oral, aboral, and circumferential) and systematic regional lymphadenectomy (LAD). To achieve tumor-free resection margins (R0), except for mucosal carcinomas (T1a N0 M0), a proximal safety margin of 5 cm (intestinal type according to Laurén) or 8 cm (diffuse type according to Laurén) in situ is usually required. The lymph node dissection of compartments I and II is referred to as D2-LAD and represents the standard lymphadenectomy for gastric carcinoma. It can be regarded as the gold standard.

The extent of resection (total versus subtotal gastrectomy) is determined by tumor location/spread and the safety margin required by the histological type.

Indications for total gastrectomy with D2-LAD include:

• All potentially resectable gastric carcinomas except mucosal carcinomas that can be treated with endoscopic resection.
• Gastric stump carcinoma

Endoscopic Therapy for Early Gastric Cancer
As early as 1962, the Japanese Research Society for Gastric Cancer defined early gastric cancer as a tumor confined to the mucosa and submucosa of the gastric wall, regardless of lymph node status, surface area, and distant metastasis. The muscularis propria of the stomach is, by definition, tumor-free.

In line with the Japanese Research Society for Gastric Cancer, early gastric cancers are macroscopically classified into tumors with polypoid growth (Type I), flat growth (Type IIa–c), or excavated growth (Type III).

Differences are observed in early cancers with the frequency of potential lymph node metastasis. There is evidence that Type I and Type II tumors more frequently than Type III tumors have already infiltrated the submucosa and are therefore not considered for endoscopic therapy. Lymph node metastases are detected in about 0–3% of cases for the mucosal type and about 4–20% for the submucosal type, in contrast to 80% in locally advanced gastric carcinomas.

Approximately 5% of patients show early gastric cancer of the mucosal type (pT1m), where a curative treatment approach through endoscopic resection is possible, as the likelihood of lymph node metastasis is extremely low. Affected patients have an excellent prognosis with a five-year survival rate of > 90%.

For minimally invasive diagnosis and simultaneous treatment of early cancer, endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), or laparoscopic partial resection of the gastric wall are available, allowing precise pathohistological processing. If histologically a submucosal carcinoma is confirmed, surgical resection and systematic lymphadenectomy must be performed, as the risk of lymph node metastasis significantly increases.

Indications for Endoscopic Resection
Superficial gastric carcinomas confined to the mucosa can be treated with endoscopic resection considering the following criteria (based on the Japanese classification of gastric carcinomas):

• Lesions < 2 cm in size in elevated types
• Lesions 1 cm in size in flat types
• Histological grade of differentiation: well or moderately differentiated (G1/G2)
• No macroscopic ulceration
• Invasion limited to the mucosa

• relevant comorbidities with inability to undergo surgery or anesthesia
• unresectable tumor, e.g., with broad infiltration of the dorsal peritoneum and infiltration of large vessels such as the hepatic artery, celiac trunk, abdominal aorta
• Any form of metastasis, except when the metastasis can be completely resolved as an R0 resection (e.g., locally limited peritoneal carcinomatosis, solitary liver metastasis, solitary distant lymph node metastasis)

In case of obstruction or endoscopically uncontrollable tumor bleeding, gastrectomy may be indicated as a palliative procedure.

Mandatory:

• Esophagogastroduodenoscopy with step biopsies (at least 5 samples)
• Ultrasound of the abdomen including the pelvis; according to S3 guidelines, the first imaging procedure for assessing liver metastases
• Endosonography for assessing the T-stage, particularly for evaluating early gastric cancer (mucosal/submucosal type). Assessment of lymph nodes in category N1 – 2 is possible, albeit with limited sensitivity and specificity.
• Thoracic and abdominal CT (with intravenous contrast)

Optional:

• Staging laparoscopy in advanced gastric carcinomas for the detection of distant metastases and peritoneal carcinomatosis. A peritoneal lavage with cytology should be additionally performed during each staging laparoscopy.
• MRI should be reserved for patients who cannot undergo CT.
• Bone scintigraphy as part of staging is not indicated without corresponding clinical symptoms.
• PET-CT is not routinely recommended for staging gastric carcinomas.
• Barium swallow studies are not suitable for staging tumors of the stomach or esophagogastric junction. The questions of tumor localization can be adequately answered by endoscopy and CT reconstruction techniques.
• There is no evidence for the benefit of determining tumor markers (e.g., CEA, Ca19-9, and Ca72-4). For all these markers, sensitivity and specificity are insufficient for primary diagnostics. Various molecular markers correlate with the prognosis of gastric cancer disease, but have not yet gained clinical relevance for therapy decisions.

Perioperative Chemotherapy
In the diagnosis of gastric carcinomas of category uT3 and resectable uT4a tumors, perioperative chemotherapy "should" be performed according to the current guideline. This is classically started preoperatively (neoadjuvant) and continued postoperatively (adjuvant).

Possibly initiate preoperative nutritional therapy in patients who have lost significant weight preoperatively.

Blood group determination, provision of erythrocyte concentrates

General Surgical Risks:

• Thromboembolism
• Pneumonia
• Urinary tract infection
• Heparin intolerance, HIT

Specific Surgical Risks:

• Final decision on the resection procedure only intraoperatively
• Injury to internal vessels and organs, e.g., spleen, bile duct
• Anastomotic insufficiency
• Duodenal stump insufficiency
• Endoluminal/intra-abdominal bleeding
• Intra-abdominal abscess, peritonitis
• Pancreatitis or pancreatic fistulas
• Wound healing disorder
• Incisional hernia

Possibly Required Extension of the Procedure:

• Cholecystectomy
• Resection of liver metastases
• Splenectomy

Indications of:

• Temporary weight loss
• Changed eating habits
• Drains, gastric tube, urinary diversion
• Possibly blood transfusion