Gastric Neoplasms its different types ,causes,diagnosis,its newest treatment

 

               Most neoplasms of the stomach are malignant, and most of those are adenocarcinoma.  The minority are lymphoma, leiomyosarcoma, and liposarcoma.  Benign neoplasms include adenomatous, hyperplastic, and hamartomatous polyps; leiomyomas; and lipomas.  Rarely, gastrinomas, carcinoids, vascular tumors, linetes plastica, fibromas, and squamous cell carcinomas occur in the stomach.            

                                    Adenocarcinoma of the stomach is the second most frequent cause of cancer death worldwide. 

• Gastric Adenocarcinoma
• Pathogenesis
• Pathology

Early gastric cancer (EGC) is gastric cancer that has not penetrated the major muscle layer of the stomach wall.  EGC can be divided into three types based on macroscopic appearance

Is gastric cancer that has penetrated the muscle layer of the stomach.  This condition also has been divided into three types: 

                                                                                                                                                                                                                                                                                                                                            i.            Polyoid.

                                                                                                                                                                                                                                                 ii.            Diffuse infiltrating or signer ring type.

                                                                                                                                                                                                                                                                                                                                 iii.            Ulcerating.

Risk factors

1. Some population groups Appear to be higher risk than others for development of gastric adenocarcinoma.

Several dietary factors have been implicated.  Increased consumption of salt appears to be a consistent finding.  Dietary nitrates also may be important.  Cigarette smoking increases risk.  However, a diet, rich in fresh fruits and vegetables, daily aspirin use, and COX-II antagonist reduce the risk.

1. Pernicious anemia and atrophic gastritis, carry a higher than average risk of gastric cancer.  Whether this is because the reduced acid allows bacteria that have the capacity to nitrosate dietary amines to carcinogenic nitrosamines to grow within the stomach or because of other effects is not clear.
3. Partial gastrectomy 15 or more years in the past was thought to be associated with a higher risk of development of adenocarcinoma
    within the gastric remnant.  Gastritis become hypo- or achlorhydric, which, as indicated may increase the risk of development of cancer.

5. Helicobacter pylori infection has been associated with gastric adenocarcinoma.  The cancer is thought to arise from gastric intestinal metaplasia that arises in patients who develop chronic atrophic gastritis with chronic infection with H. Pylori.  Especially those strains that are CagA+ appear to be more carcinogenic than CagA – strains.
   daignosis

1.. Clinical presentation

a. EGC

b. Asymptomatic but when occur, vague symptoms advanced gastric cancer.

                      i.            Symptoms are primarily abdominal pain and weight loss, which may be accompanied by anorexia, weakness, gastrointestinal bleeding, and signs of gastric obstruction, such as early satiety or vomiting.

2. Physical examination.  An epigastric mass, an enlarged liver due to metastases, or ascites may be evident.  An umbilical mass, known as a Sister Joseph's nodule, is unusual.  Metastasis to the ovaries has been called a Krukenberg's tumor, although this eponym also has been applied to colonic and other gastrointestinal tumors that metastasize to the ovaries.
   
   Upper gastrointestinal x-ray series versus endoscopy.
3. At endoscopy, six to eight biopsies of the ulcer edges.
4. Endocopic ultrasound.
5. Serum carcinoembryonic antigen (CEA).
6. Hematocrit and hemoglobin levels may be normal but typically are decreased in advanced gastric cancer due chornic disease.
7. An elevated alkaline phosphatase level liver. An elevated 5' –nucleotidase level confirms that the liver is affected .
8. Computed tomography (CT) of the abdomen should be performed to survey for liver 
9. metastases
10. Surgery currently is the only hope of cure.  About 20% of patients are deemed inoperable because of the extent of disease or high operative risk. Of the remaining 80% who undergo surgery, about half undergo a curative resection, and the other half are given palliative treatment for bleeding or ob struction.  However, only about 20% of patients who have had a curative resection survive 5 years.  Results might be better with extensive lymph node dissection and lymphadenectomy.

3. Chemotherapy and radiotherapy.  Both chemotherapy and radiotherapy alone for gastric cancer have been disappointing.  If the patient's condition is operable, the initial resection of as much tumor mass as possible seems to improve the efficacy of chemotherapy and radiotherapy.adjuvant chemotherapy using 5-fluororacil, mitomycin, doxorubicin, Cisplatin, and irinotecan seems to improve survival.  Adjuvant radiotherapy alone has no effect on longterm survival.  Combined chemotherapy and radiation in the adjuvant setting improves overall survival.
4. Other treatment measures. Patients with gastric cancer require careful attention to nutritional needs.  Partial or complete gastric resection imposes additional nutritional consequences supplemental vitamins, particularly vitamin B12, and minerals such as calcium and iron.

1. . Other Gastric Tumors
   
   Malignant tumors:

                Other malignant tumors include lymphoma, leiomyosarcoma, liposarcoma, and carcinoid.  Of these, primary gastric lymphomas account for most of the noncarcinomatous gastric malignancies.  The stomach can also be involved secondarily by disseminated lymphoma or by metastatic cancer from other sites.

1. 
   Clinical presentation and diagnosis:

                present clinically with abdominal pain, weight loss, anorexia, and vomiting, signs and symptoms that are similar to those observed in patients with adenocarcmoma of the stomach.  The methods of diagnosis are also similar.

2. Prognosis and treatment: 

                Because lymphoma responds better than adenocarcinoma to radiation and chemotherapy, the prognosis is better.

B. MALT Lymphoma: 

                Low-grade B-cell lymphomas of mucosa associated lymphoid tissue (MALT) are thought to arise within organized lymphoid tissue in the gastric mucosa that is most frequently acquired in response to H. pylori infection.  Longterm remissions can be induced in the low-grade MALT lymphomas in 70% to 80% of cases by the successful eradication of the H. pylori infection.  The lymphomas that are most likely to respond to the H. pylori eradication are those that are located superficially within the gastric mucosa.  Recurrences of low-grade lymphoma are encountered in patients treated by H. pylori eradication.  Deeper and higher grade lesions need to be treated as B-cell lymphomas.

C. Polypoid lesions and benign tumors.  Into the lumen of a viscus and thus does not necessarily connote benign or malignant histopathology.  In common medical usage, however, the term polyp.

1.     Histologic types. Gastric polyps are adenomatous, hyperplastic or hamartomatous.  Of these, only adenomatous polyps and carcinoids appear to have malignant potential.

2.     Diagnosis.  Often, benign polypoid lesions are discovered incidentally during upper GI x-ray series or endoscopy.

3.     Treatment.  The diagnosis of frank carcinoma, lymphoma, or other malignancy leads to appropriate treatment of that condition.  Removal of an adenomatous polyp removes the risk of malignant degeneration.  The diagnosis of a benign, nonadenomatous polypoid lesion is reassuring in that the lesion is not cancerous and will not become cancerous.