Definition
A.A malignant tumor of the stomach.
B.Most cancers of the stomach are adenocarcinomas: Malignant tumors that develop from the cells in the lining of the stomach.
Incidence
A.Gastric cancer is the third most common cause of cancer-related mortality worldwide.
B.In the United States, approximately 22,220 patients are diagnosed annually, 10,990 of whom are expected to die from gastric cancer.
C.The worldwide incidence of gastric cancer has declined over the past few decades, partly due to the recognition of risk factors such as Helicobacter pylori and dietary risks.
D.The overall 5-year relative survival rate of all people with stomach cancer in the United States is about 30%.
Pathogenesis
A.Gastric cancer is a malignant neoplasm that arises anywhere between the gastroesophageal junction and pylorus.
B.Most tumors are epithelial in origin and classified as adenocarcinomas.
C.H. pylori infection is strongly associated with the presence of precancerous lesions that manifest into cancer proliferation. Over 80% of gastric cancers are thought to be attributed to H. pylori infection.
Predisposing Factors
A.Chronic gastritis caused by:
1.Chronic H. pylori infection.
2.Pernicious anemia.
3.Diet.
a.Diet high in salt and salt-preserved foods, nitrates, nitrites, fried foods, processed meats, alcohol.
b.Diets low in vegetables (diets high in fruits, vegetables, and fiber are protective against gastric cancer).
B.Obesity.
C.Smoking.
D.Prior gastric surgery.
E.Prior abdominal radiation.
F.Male gender.
G.African American race.
H.Inherited germline mutations in TP53, BRCA2, and CDH1.
Subjective Data
A.Common complaints/symptoms.
1.Unintentional weight loss secondary to insufficient caloric intake caused by tumor related anorexia, nausea, abdominal pain, early satiet-, and/or dysphagia.
2.Bowel changes: Melena or black tarry stools, constipation if treating pain, nausea, anemia, change in nature or pattern of bowel habits if an obstructing tumor.
3.Persistent vague, epigastric abdominal pain.
4.Dysphagia, especially for tumors in the proximal stomach or gastroesophageal junction.
5.Fatigue secondary to anemia from bleeding tumors.
Physical Examination
A.Focused areas of the physical examination for suspected gastric cancer should include:
1.Vital signs.
a.Evaluate weight and recent trends for unintentional weight loss.
b.Heart rate: Tachycardia suggestive of dehydration secondary to poor oral intake.
2.Head, ear, eyes, nose, and throat (HEENT).
a.Evaluate oral mucosa for paleness suggestive of anemia.
b.Evaluate tongue for evidence of thrush.
c.Quality of dentition.
3.Palpate neck and cervical nodal chains for adenopathy suggestive of metastasis.
4.Abdominal examination.
a.Observe for contour of the abdomen and distention, evidence of cachexia.
b.Evaluate the skin, subcutaneous tissue, and umbilicus.
c.Auscultate abdomen noting the frequency and character of bowel sounds, normally 5 to 30 gurgling sounds per minute.
d.Palpation: Prior to palpation, ask about any tender areas and palpate this area last; commonly tender in the epigastric region secondary to reflux.
e.Evaluate for abdominal firmness suggesting carcinomatosis and ascites.
f.Evaluate for nodularity in the umbilical area suggestive of a Sister Mary Joseph nodule demonstrating umbilical metastasis.
g.Palpate for hepatosplenomegaly suggestive of metastasis.
Diagnostic Tests
A.Complete history and physical examination.
B.Laboratory tests including complete blood count (CBC) with differential and comprehensive metabolic panel (CMP).
C.Upper gastrointestinal (GI) series with barium swallow as initial screening for patients with dysphagia.
D.CT of the chest, abdomen, and pelvis.
E.Esophagogastroduodenoscopy (EGD) for tissue diagnosis and anatomic location.
F.Endoscopic ultrasound (EUS) if no evidence of distant metastatic disease.
G.Diagnostic laparoscopy with biopsy and peritoneal lavage to evaluate for radiographically occult metastatic disease and carcinomatosis.
H.Diagnosis: Tissue diagnosis and anatomic localization of the primary tumor are best obtained by upper GI endoscopy.
I.Staging.
1.Gastric cancers that are 5 cm or more from the gastroesophageal junction are staged using the
tumor, node, metastasis (TNM) system as gastric cancers.
2.Gastric cancers that are less than 5 cm from the gastroesophageal junction are staged using the TNM system as esophageal cancers.
Differential Diagnosis
A.Gastritis.
B.Gastroenteritis.
C.Esophagitis.
D.Esophageal cancer.
E.Peptic ulcer disease.
F.Neoplasm.
Evaluation and Management Plan
A.General plan and treatment.
1.Tissue diagnosis and staging evaluation are required for treatment planning.
2.Surgical resection is required for cure of gastric cancer.
3.Surgery followed by chemotherapy +/− radiation is the mainstay of treatment.
4.Surgery.
5.Advanced metastatic disease (stage IV) is treated with palliative chemotherapy or on a clinical trial.
B.Acute care issues in gastric cancer.
1.Gastric cancer patients are often only admitted for surgical resection.
2.Postoperative gastric surgery patients without complications will spend 7 to 10 days in the hospital after surgery.
3.The primary focus in the postoperative inpatient setting is nutrition, pain control, monitoring lab work, wound care, and early ambulation.
a.Routine blood work including CBC with differential, electrolyte panel, blood urea nitrogen (BUN), and creatinine must be monitored for anemia, infection, electrolyte imbalance/need for replacement, and kidney function.
b.The incision site will be monitored daily for signs of infection and proper healing.
c.The postgastrectomy patient will have a nasogastric tube in place. Once there is no evidence of anastomotic leak, the nasogastric tube may be removed.
d.Supplemental jejunostomy tube feedings will be initiated on postoperative day one and will continue until oral intake is adequate.
e.Oral feeding is started 4 to 7 days postoperatively.
f.Upper GI studies are done as indicated (fever, tachycardia, tachypnea, leukocytosis).
g.Early ambulation reduces risk of postoperative pneumonia, ileus, and thrombosis. The goal is to have the patient out of bed the day after the procedure as tolerated.
h.Postoperative cancer patients have a hypercoagulable state; prophylactic enoxaparin is initiated postoperatively and continued for 28 days.
Follow-Up
A.Postgastrectomy complications.
1.Duodenal stump or anastomotic leak.
a.Anastomotic leak: Arises from any of the suture/staple lines of the anastomosis.
b.Duodenal stump leak: Most feared complication of gastrectomy.
c.Symptoms: Severe abdominal pain, fever, tachycardia, hypotension.
d.CT abdomen is indicated.
i.Findings: Pneumoperitoneum, extraluminal contrast, fluid collection, and/or abscess.
e.Upper GI series (with Gastrografin) may also be performed to assess leak.
f.Treatment.
i.Broad-spectrum antibiotics.
ii.Consider percutaneous drainage of fluid collection/abscess by interventional radiology.
iii.If leak persists or patient is hemodynamically unstable, patient should be taken to the operating room for exploration, drainage, and repair.
2.Dumping syndrome.
a.Postgastrectomy patients commonly have rapid transit and report diarrhea.
b.Dumping syndrome is characterized by diaphoresis, abdominal cramps, and watery diarrhea shortly after intake of concentrated sweets and hyperosmolar liquids.
c.Diagnosis is based on clinical symptoms.
i.Gastric emptying studies or upper GI series may be performed.
d.Treatment.
i.Primary goal includes dietary changes with frequent small meals that are high in fiber and low in carbohydrates. Avoid food triggers (e.g., simple sugar).
ii.Octreotide may help but is not typically required.
Consultation/Referral
A.In patients with suspected gastric cancer, consults should be made to gastroenterology, radiation oncology, medical oncology, and surgery.
Special/Geriatric Considerations
A.Most cases of gastric cancer affect the elderly.
B.Aggressive treatment and surgery should not be withheld from patients solely due to chronological age.
C.Life expectancy, quality of life, and patient’s functional status need to be taken into consideration in conjunction with patient wishes.
Bibliography
National Cancer Institute. (2016, September 12). Surveillance, epidemiology, and end results program. Retrieved from https://seer.cancer.gov/faststats/selections.php?series=cancer
Siegel, R., Ma, J., Zou, Z., & Jemal, A. (2014). Cancer statistics, 2014. CA: A Cancer Journal for Clinicians, 64(1), 9–29.
Zhu, A. L., & Sonnenberg, A. (2012). Is gastric cancer again rising? Journal of Clinical Gastroenterology, 46, 804–806.