What is staging laparoscopy and why is it done before gastric cancer surgery?

Staging laparoscopy is a minimally invasive operation performed before any planned gastrectomy for gastric cancer. Small tumors on the peritoneal surface (peritoneal metastases) may not be visible on CT or PET scans. A staging laparoscopy directly examines the peritoneum and obtains cytology from peritoneal washings. If peritoneal disease is found, the patient is spared a major unnecessary surgery and directed to systemic therapy instead. This is routinely performed for locally advanced (T3/T4) gastric cancers.

Is chemotherapy given before or after surgery for gastric cancer?

For most resectable gastric adenocarcinomas, perioperative chemotherapy is standard. The FLOT regimen (5-FU, leucovorin, oxaliplatin, docetaxel) is typically given for several cycles before surgery to shrink the tumor, then continued after surgery. This approach improves survival compared to surgery alone. For patients with MSI-H (microsatellite instability-high) tumors, immunotherapy is also incorporated. Neoadjuvant chemotherapy also provides an early test of tumor biology.

Gastric & Upper GI Cancer Surgery | Camilo Correa, MD

Q: What is the standard surgical treatment for gastric cancer?

The type of gastrectomy depends on tumor location. Proximal gastric cancers (near the gastroesophageal junction) and diffuse-type (signet ring cell) gastric cancers typically require total gastrectomy with D2 lymphadenectomy. Distal cancers may be treated with subtotal (partial) gastrectomy, which generally preserves better nutritional function. D2 lymphadenectomy — removing the perigastric and regional lymph nodes — is the standard of care and improves survival compared to limited lymph node removal.

Q: What is a GIST and how is it treated?

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors arising from the interstitial cells of Cajal in the GI tract wall. The stomach is the most common site (~60%). Most GISTs have a mutation in the KIT gene. For resectable GISTs, surgical excision achieving negative margins is the goal — without the need for lymphadenectomy. Large or high-risk GISTs are treated with neoadjuvant imatinib (a targeted therapy) to shrink the tumor before surgery. Tumor rupture must be avoided, as it worsens prognosis.

Overview

Gastric Cancer

Gastric cancer (stomach cancer) remains a significant global health problem. In the United States, most gastric cancers are adenocarcinomas — arising from the glandular cells lining the stomach. They are classified by location (proximal near the gastroesophageal junction, or distal near the pylorus) and by histologic type (intestinal vs. diffuse/signet ring cell).

Surgery remains the only curative treatment, but it is almost always delivered as part of a multimodal regimen that includes perioperative chemotherapy. Molecular profiling of the tumor (HER2, MSI, PD-L1) now guides treatment selection for each patient.

Dr. Correa's approach prioritizes staging laparoscopy before any major gastrectomy, to avoid unnecessary surgery in patients with occult peritoneal disease that imaging cannot detect.

Key Facts

Staging laparoscopy firstRoutine before major resection for cT3–T4 disease — rules out peritoneal spread

Perioperative FLOT + immunotherapyMATTERHORN trial results have established chemo-IO as the new standard for resectable gastric adenocarcinoma; early adopted at Mount Sinai

D2 lymphadenectomyStandard-of-care nodal dissection; improves staging accuracy and likely survival

Multidisciplinary Tumor BoardAll cases reviewed by gastric surgery, medical oncology, GI, radiology, and pathology

Symptoms & Diagnosis

Presentation & Workup

Gastric cancer is often diagnosed at an advanced stage because early disease may be asymptomatic or cause only vague symptoms.

Common Symptoms

Early satiety and bloating
Unintentional weight loss
Persistent nausea or vomiting
Epigastric (upper abdominal) pain or discomfort
Dysphagia (for proximal/GEJ tumors)
Iron-deficiency anemia from occult bleeding

Diagnostic Workup

Upper GI endoscopy with biopsy (diagnosis)
CT scan of chest, abdomen, pelvis (staging)
Endoscopic ultrasound (EUS) for T and N staging
PET scan for select patients
Staging laparoscopy before major resection
Tumor molecular profiling (HER2, MSI, PD-L1, CLDN18.2)

Surgical Options

Types of Gastrectomy

The type of gastric resection is determined by tumor location, histologic subtype, and the need for adequate surgical margins.

Total Gastrectomy

Removal of the entire stomach, used for proximal tumors (GEJ, fundus, body), diffuse-type/signet ring cell histology, or large tumors where partial removal would not achieve negative margins. Reconstruction is performed with a Roux-en-Y esophagojejunostomy.

Subtotal (Distal) Gastrectomy

Removal of the distal 75–80% of the stomach, sparing the proximal portion. Used for antral and pyloric tumors with adequate proximal margin. Preserves better nutritional absorption than total gastrectomy. Reconstruction via Roux-en-Y or Billroth II gastrojejunostomy.

      D2 Lymphadenectomy — Standard-of-care nodal dissection that removes the perigastric and regional lymph node basins along the major arterial pedicles. A minimum of 15 lymph nodes is required for accurate staging. Dr. Correa routinely performs D2 dissection for all curative-intent gastrectomies.
    

Perioperative Treatment

FLOT + Immunotherapy

Perioperative FLOT (docetaxel, oxaliplatin, leucovorin, 5-FU) has been the standard of care for resectable gastric adenocarcinoma since the FLOT4 trial. The landmark MATTERHORN trial added durvalumab (a PD-L1 checkpoint inhibitor) to perioperative FLOT, demonstrating significantly improved pathologic complete response rates and event-free survival. Perioperative chemo-IO has now become the new standard for eligible patients.

This is an area of rapid, practice-changing development. Dr. Correa works closely with the gastric oncology team to ensure patients are offered the most current regimens — including clinical trial enrollment when appropriate.

Molecular profiling of the tumor guides additional therapy selection: HER2-positive tumors receive trastuzumab; MSI-H tumors are particularly strong candidates for immunotherapy and may achieve pathologic complete response, opening the possibility to avoid surgery in some cases; CLDN18.2-positive tumors may benefit from additional treatment options.

Why Treat Before Surgery?

Neoadjuvant therapy shrinks the primary tumor to improve resectability, treats micrometastatic disease early, and provides an in vivo test of tumor biology. Patients who achieve pathologic complete response have a markedly better prognosis. Dr. Correa coordinates neoadjuvant planning with medical oncology at the first consultation — so no time is lost.

Gastrointestinal Stromal Tumor

GIST

GISTs are the most common mesenchymal tumors of the GI tract. The stomach is the most frequent site (~60%), followed by the small intestine and duodenum. Unlike adenocarcinoma, GIST does not spread to lymph nodes, and lymphadenectomy is not required.

Most GISTs harbor a mutation in the KIT gene (or less commonly PDGFRA), which is the target of imatinib and other tyrosine kinase inhibitors (TKIs). Molecular testing of the resected tumor guides decisions about adjuvant treatment.

Resectable GIST: surgical excision with negative margins, without lymphadenectomy. Minimally invasive approach when oncologically appropriate.

Large or borderline GIST: neoadjuvant imatinib for 6–12 months to shrink tumor, reduce operative morbidity, and avoid multivisceral resection.

Avoid rupture: tumor rupture during surgery upstages the disease and substantially worsens prognosis. Careful surgical technique and appropriate preoperative planning are essential.

Presenting Symptom: Bleeding

Gastric and duodenal GISTs commonly present with gastrointestinal bleeding — either as melena (dark stools), hematemesis (vomiting blood), or chronic iron-deficiency anemia. Because GISTs are submucosal tumors, they can ulcerate the overlying mucosa and bleed into the GI lumen. GI bleeding is often the first — and sometimes only — symptom that prompts endoscopy and leads to the diagnosis.

Adjuvant Therapy

High-risk GISTs — defined by large size (>5–10 cm), high mitotic index (>5/50 HPF), non-gastric location, or tumor rupture — carry a significant risk of recurrence after resection. Three years of adjuvant imatinib (400 mg/day) reduces recurrence risk and improves recurrence-free survival. Mutation type matters: KIT exon 11 mutations respond best; PDGFRA D842V mutations are resistant to imatinib.

FAQ

Frequently Asked Questions

What is the standard surgical treatment for gastric cancer?

Surgery type depends on tumor location. Proximal and diffuse-type gastric cancers require total gastrectomy with D2 lymphadenectomy. Distal cancers may allow subtotal gastrectomy. D2 lymphadenectomy — removing perigastric and regional lymph nodes — is the standard of care and improves both staging accuracy and survival.

What is staging laparoscopy and why is it done first?

Staging laparoscopy is a minimally invasive procedure that directly examines the peritoneal surfaces and obtains peritoneal washings for cytology. Small peritoneal metastases may not be visible on CT or PET scans. If found, the patient is spared an unnecessary major surgery and directed to systemic therapy. This is routinely performed for locally advanced (T3/T4) gastric cancers before any planned gastrectomy.

Is chemotherapy given before or after surgery, and what is the role of immunotherapy?

Perioperative FLOT chemotherapy has been the standard of care for resectable gastric adenocarcinoma, given before and after surgery. The MATTERHORN trial demonstrated that adding durvalumab (immunotherapy) to perioperative FLOT significantly improves pathologic complete response rates and event-free survival. Perioperative chemo-IO is now the new standard for eligible patients and has been early adopted at Mount Sinai. Tumor molecular profiling (HER2, MSI, PD-L1, CLDN18.2) guides the full regimen for each patient.

What is a GIST and how is it treated?

GISTs are mesenchymal tumors of the GI tract wall, most commonly arising in the stomach, driven by KIT or PDGFRA mutations. They often present with gastrointestinal bleeding (melena, hematemesis, or anemia) — particularly for gastric and duodenal tumors. Resectable GISTs are surgically excised without lymphadenectomy. Large or borderline GISTs are treated with neoadjuvant imatinib before surgery to reduce tumor size. Tumor rupture must be avoided as it worsens prognosis significantly. High-risk GISTs receive 3 years of adjuvant imatinib after surgery to reduce the risk of recurrence.

Expert Gastric Cancer Evaluation at Mount Sinai

Optimal gastric cancer treatment requires coordination of surgery, oncology, endoscopy, radiology, and pathology. Dr. Correa leads this process from the first consultation.

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