Practice Essentials
Gastric cancer is the sixth most common cancer and the third most common cause of cancer-related death in the world.
Although rates are low in North America and Northern Europe—in the United States, stomach malignancy is currently the 15th most common cancer
—the disease remains difficult to cure in Western countries, primarily because most patients present with advanced disease. See the image below.
Early gastric cancer in the gastric body. Courtesy of Wikimedia Commons (author Med_Chaos).
Signs and symptoms
Early gastric cancer has no associated symptoms; however, some patients with incidental complaints are diagnosed with early gastric cancer. Most symptoms of gastric cancer reflect advanced disease. All physical signs in gastric cancer are late events. By the time they develop, the disease is almost invariably too far advanced for curative procedures.
Signs and symptoms of gastric cancer include the following:
Indigestion
Nausea or vomiting
Dysphagia
Postprandial fullness
Loss of appetite
Melena or pallor from anemia
Hematemesis
Weight loss
Palpable enlarged stomach with succussion splash
Enlarged lymph nodes such as Virchow nodes (ie, left supraclavicular) and Irish node (anterior axillary)
Late complications of gastric cancer may include the following features:
Pathologic peritoneal and pleural effusions
Obstruction of the gastric outlet, gastroesophageal junction, or small bowel
Bleeding in the stomach from esophageal varices or at the anastomosis after surgery
Intrahepatic jaundice caused by hepatomegaly
Extrahepatic jaundice
Inanition from starvation or cachexia of tumor origin
See Presentation for more detail.
Diagnosis
Testing
The goal of obtaining laboratory studies is to assist in determining optimal therapy. Potentially useful tests in patients with suspected gastric cancer include the following:
CBC: May be helpful to identify anemia, which may be caused by bleeding, liver dysfunction, or poor nutrition; approximately 30% of patients have anemia
Electrolyte panels
Liver function tests
Tumor markers such as CEA and CA 19-9: Elevated CEA in 45-50% of cases; elevated CA 19-9 in about 20% of cases
Imaging studies
Imaging studies that aid in the diagnosis of gastric cancer in patients in whom the disease is suggested clinically include the following:
Esophagogastroduodenoscopy (EGD): To evaluate gastric wall and lymph node involvement
Double-contrast upper GI series and barium swallows: May be helpful in delineating the extent of disease when obstructive symptoms are present or when bulky proximal tumors prevent passage of the endoscope to examine the stomach distal to an obstruction
Chest radiography: To evaluate for metastatic lesions
CT scanning or MRI of the chest, abdomen, and pelvis: To assess the local disease process and evaluate potential areas of spread
Endoscopic ultrasonography (EUS): Staging tool for more precise preoperative assessment of the tumor stage
Biopsy
Biopsy of any ulcerated lesion should include at least six specimens taken from around the lesion because of variable malignant transformation. In selected cases, endoscopic ultrasonography may be helpful in assessing depth of penetration of the tumor or involvement of adjacent structures.
Histologically, the frequency of different gastric malignancies is as follows
:
Adenocarcinoma – 90-95%
Lymphomas – 1-5%
Gastrointestinal stromal tumors (formerly classified as either leiomyomas or leiomyosarcomas) – 2%
Carcinoids – 1%
Adenoacanthomas – 1%
Squamous cell carcinomas – 1%
See Workup for more detail.
Management
Surgery
The surgical approach in gastric cancer depends on the location, size, and locally invasive characteristics of the tumor.
Types of surgical intervention in gastric cancer include the following:
Total gastrectomy, if required for negative margins
Esophagogastrectomy for tumors of the cardia and gastroesophageal junction
Subtotal gastrectomy for tumors of the distal stomach
Lymph node dissection: Controversy exists regarding extent of dissection; the National Comprehensive Cancer Network (NCCN) recommends D2 dissections over D1 dissections; a pancreas- and spleen-preserving D2 lymphadenectomy provides greater staging information and may provide a survival benefit while avoiding its excess morbidity when possible
Chemotherapy
Antineoplastic agents and combinations of agents used in managing gastric cancer include the following:
Platinum-based combination chemotherapy: First-line regimens include epirubicin/cisplatin/5-FU or docetaxel/cisplatin/5-FU; other regimens include irinotecan and cisplatin; other combinations include oxaliplatin and irinotecan
Trastuzumab in combination with cisplatin and capecitabine or 5-FU: For patients who have not received previous treatment for metastatic disease
Ramucirumab for the treatment of advanced stomach cancer or gastroesophageal (GE) junction adenocarcinoma in patients with unresectable or metastatic disease following therapy with a fluoropyrimidine- or platinum-containing regimen
Pembrolizumab for gastric or GE junction carcinoma in patients expressing PD-L1 with disease progression on or after 2 or more prior lines of therapy including fluoropyrimidine- and platinum-containing chemotherapy and if appropriate, HER2/neu-targeted therapy
Nivolumab in combination with fluoropyrimidine- and platinum-containing chemotherapy for first-line therapy of advanced or metastatic gastric cor GE junction cancer
Trastuzumab deruxtecan for locally advanced or metastatic HER2-positive gastric or GE junction adenocarcinoma in patients who have received a prior trastuzumab-based regimen
Neoadjuvant, adjuvant, and palliative therapies
Potentially useful therapies in gastric cancer include the following:
Neoadjuvant chemotherapy
Intraoperative radiotherapy (IORT)
Adjuvant chemotherapy (eg, 5-FU)
Adjuvant radiotherapy
Adjuvant chemoradiotherapy
Palliative radiotherapy
Palliative-intent procedures (eg, wide local excision, partial gastrectomy, total gastrectomy, simple laparotomy, gastrointestinal anastomosis, bypass)
See Treatment for more detail.