Gastric tumors

Gastric cancer is the fourth most common cancer and the second leading cause of cancer death Especially prevalent is SE Asia and South America Incidence is decreasing in developed countries In developed countries Japan and Korea have the highest rates of the disease

Epidemiology Disease of the early Twice as common in blacks Higher incidence in groups of lower socioeconomic status

Risk factors Helicobacter pylori (atrophic gastritis, intestinal metaplasia, dysplasia) Dietary factors: high salt foods, smoked or salted meat, low fruit and vegetables Hereditary risk factors (E-cadherin, FAP, Li Fraumeni syndome, HNPCC Pernicious anemia Polyps Previous gastrectomy or gastrojejunostomy Menetrier’s disease

pathology Common classifications – Borrmann’s classification – Lauren classification – WHO classification

Lauren classification

Several decades ago, the large majority of gastric cancers were in the distal stomach. Recently, there has been a proximal migration of tumors the distribution is closer to 40% distal, 30% middle, and 30% proximal

Pathology The important prognostic factors are histologic: depth of invasion and lymph node involvement Pathologic staging is by TNM stage Spread is by direct spread, lymphatic, hematogenous and transperitoneal routes

World Health Organisation Histologic Typing of Gastric Cancer

Clinical features May be asymptomatic if screen detected Most are advanced at diagnosis Weight loss Decreased food intake (anorexia, early satiety) Abdominal pain (recent onset dyspepsia) Nausea & vomiting Acute GI bleeding Chronic occult blood loss, iron deficiency anemia

Dysphagia Paraneoplastic syndromme (Trousseau’s syndrome, acanthosis nigricans, peripheral neuropathy)

Complications Bleeding Obstruction Perforation

Physical findings Usually normal Signs of weight loss Virchow’s node Sister Joseph’s nodule Abdominal mass (large tumor, liver metastasis, Krukenberg tumor) Blummer’s shelf Malignant ascites

Work up Full blood count Serum electrolytes, creatinine, blood urea nitrogen Coagulation studies Upper gastrointestinal endoscopy Endoscopic ultrasound CT/MRI Diagnostic laparoscopy

Treatment Complete resection of the gastric tumor with a wide margin of normal stomach remains the standard of care for resection with curative intent (R0, R1, R2) Distal gastrectomy with Bilroth II reconstruction Total gastrectomy with esopgagojejunostomy Proximal gastrectomy Lymph node dissection (D1, D2, D3) Bypass surgery (palliative)

Adjuvant treatment Chemotherapy and radiotherapy are useful in improving survival Agents are Cisplatin, Epirubicin, 5-Fluorouracil

Gastric Lymphomas Gastric lymphomas generally account for about 4% of gastric malignancies. Over half of patients with non-Hodgkin's lymphoma have involvement of the GI tract. The stomach is the most common site of primary GI lymphoma, and over 95% are non- Hodgkin's type. Most are B-cell type, thought to arise in MALT

About half of gastric lymphomas are histologically low grade, and about half are high grade. The normal stomach is relatively devoid of lymphoid tissue. However, in the setting of chronic gastritis, the stomach acquires MALT, which can undergo malignant degeneration. Again, H. pylori is thought to be the culprit

Remarkably, when the H. pylori is eradicated and the gastritis improves, the low-grade MALT lymphoma often disappears Fever, weight loss, and night sweats occur in about 50% of patients with gastric lymphoma High-grade gastric lymphoma require aggressive oncologic treatment for cure Present with many of the same symptoms as gastric cancer patients.

High-grade gastric lymphomas are treated with chemotherapy and radiation Palliative gastrectomy for tumor complications also has a role

Gastrointestinal stromal tumors Gastrointestinal stromal tumors (GISTs) are the most common sarcomatous tumors of the GI tract. Derived from the interstitial cells of Cajal, an intestinal pacemaker cell. usually found in the stomach (40% to 60%), small intestine (30%), and colon (15%

present at any age, although most typically present in patients older than 50 years. They generally have an equal male-to-female ratio or a slight male predominance. Most present symptomatically, typically with bleeding or vague abdominal pain or discomfort. Bleeding is generally in the form of melena or, less frequently, frank hematemesis. Tumor rupture with intra-abdominal hemorrhage

They are now frequently identified by immunohistochemical staining for the c-kit proto-oncogene (CD117), in >90% of these tumors, and for CD34, in 80% of GISTs. treatment is complete surgical resection. wide local excision, enucleation, sleeve gastrectomy, or total gastrectomy Adjuvant therapy, is with the tyrosine kinase inhibitor imatinib (Gleevec)

Gastric carcinoids Overall, carcinoid tumors are a rare malignancy (0.49% of all malignancies) that arise from neuroendocrine precursor cells can present at any site in the body. The most common location is the GI tract, encompassing almost 68% of all carcinoids. The most common sites in the GI tract are the small intestine, rectum, and appendix. The stomach is the location of almost 8% of GI carcinoids,

The treatment for localized carcinoids is complete removal Patients with multiple gastric carcinoids may require total gastrectomy. For patients with recurrent or metastatic disease, somatostatin analogues can be used to decrease the burden of disease and treat carcinoid syndrome

Benign gastric neoplasms Epithelial polyps are the most common benign tumor of the stomach There are essentially five types of benign epithelial polyps adenomatous, hyperplastic (regenerative), hamartomatous, inflammatory, and heterotopic (e.g., ectopic pancreas).

The most common gastric polyp (about 75%) is the hyperplastic or regenerative polyp, frequently occurs in the setting of gastritis and has a low malignant potential. Adenomatous polyps may undergo malignant transformation, similarly to adenomas in the colon. They constitute about 10 to 15% of gastric polyps.

Hamartomatous, inflammatory, and heterotopic polyps have negligible malignant potential (including fundic gland polyps). Polyps that are symptomatic, >2 cm, or adenomatous should be removed, usually by endoscopic snare polypectomy. Consideration should also be given to removing hyperplastic polyps, especially if large. Repeat EGD for surveillance should be done following removal of adenomatous polyps, and, perhaps, after removal of hyperplastic polyps as well.

Leiomyoma The typical leiomyoma is submucosal and firm. If ulcerated, it has an umbilicated appearance and may bleed. Lesions <2 cm are usually asymptomatic and benign. Larger lesions have greater malignant potential and a greater likelihood to cause symptoms such as bleeding, obstruction, or pain. Asymptomatic lesions <2 cm may be carefully observed or enucleated if fine-needle aspiration and immune markers confirm smooth muscle tumor; larger lesions and symptomatic lesions should be removed by wedge resection (often possible laparoscopically Lipoma