ABC of the upper gastrointestinal tract: Cancer of the stomach and pancreas

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Abstract
Cancer of the stomach Gastric adenocarcinoma is rare below the age of 40 years, and its incidence peaks at about 60 years of age. Men are affected twice as often as women. Chronic atrophic pangastritis associated with H pylori infection is one of the most important risk factors for distal gastric cancer. Risk factors for gastric cancer H pylori infection and atrophic gastritis Pernicious anaemia Adenomatous gastric polyps Partial gastrectomy Abnormalities in E-cadherin gene Family history of gastric cancer Clinical presentation Symptoms may not occur until local disease is advanced. Patients may have symptoms and signs related to secondary spread (principally to the liver) and to the general effects of advanced malignancy, such as weight loss, anorexia, or nausea. Epigastric pain is present in about 80% of patients and may be similar to that from a benign gastric ulcer. If caused by obstruction of the gastric lumen, it is relieved by vomiting. Carcinoma of the gastric cardia may cause dysphagia. View this table: In this window In a new window Signs and symptoms of gastric cancer Constant abdominal pain, and particularly back pain, are sinister symptoms implying local invasion by tumour. Chronic or acute bleeding from the tumour may occur, with consequent symptoms. There is often little to be found on examination, but there may be a palpable epigastric mass. The classic Troisier's sign (left supraclavicular lymph node enlargement) is rare. Investigations and staging Endoscopy and barium meal are the principal investigations. Endoscopy allows direct visualisation and biopsy of the carcinoma. Differentiation between benign and malignant gastric ulcers at endoscopy can be difficult, and several biopsies are therefore taken (ideally six) from all parts of the ulcer. Diagnostic accuracy approaches 100% if 10 samples are taken. A benign gastric ulcer is probably not a premalignant condition. View larger version: In this window In a new window Barium meal showing large obstructing carcinoma of the body of the stomach A barium study gives a better impression of the anatomy of the tumour and the degree of obstruction. It is also helpful for diagnosis of linitis plastica, which may be missed at gastroscopy. In the presence of dysphagia it is important to request a barium swallow and meal rather than a barium meal alone. Endoscopy and barium studies are complementary. If the first investigation is negative in a patient with sinister symptoms the other test is indicated. If a diagnosis of benign ulceration is made it is essential to repeat the endoscopy and biopsies after four to eight weeks of medical treatment to confirm ulcer healing and the benign nature of the lesion. Staging of the disease by computed tomography of the thorax and abdomen, and sometimes by laparoscopy or endoscopic ultrasonography, is appropriate only in those patients who are proceeding to surgery. View larger version: In this window In a new window Light micrograph of human stomach cancer. Most of the cells seen here are cancerous, having large, irregular shapes and multiple nuclei Differential diagnosis Once a gastroscopy or barium study has been performed, there are usually few problems with the diagnosis of gastric carcinoma. The difficulty lies in deciding which patients need urgent investigation of their presenting symptoms. A good initial symptomatic response to acid suppression does not exclude malignancy. Guidelines from the British Society of Gastroenterology for the investigation of dyspepsia suggest that all patients aged over 45 years should undergo endoscopy, whereas those under 45 need endoscopy only if they have symptoms or signs that raise suspicion of malignancy. Treatment Curative treatment The decision to perform a gastrectomy depends on the patient's general state of health and nutrition and the preoperative staging of the cancer. If there is no evidence of local invasion or of metastatic spread, resection is offered as a potential cure. Overall perioperative mortality is about 2%. Long term survival depends principally on the extent of lymph node metastases. View larger version: In this window In a new window Total gastrectomy for treatment of gastric cancer (left) and subsequent reconstruction by Roux-en-Y anastomosis (right) Chemotherapy may have an increasingly important role to play in treating gastric carcinoma. Recent emphasis has been on preoperative chemotherapy in order to “downstage” the tumour. There seems to be little place for radiotherapy in the treatment of gastric carcinoma at present. Palliative treatment Patients with distal obstructing tumours may benefit from a subtotal gastrectomy or gastrojejunostomy despite the presence of metastases. Stenting of tumours of the gastric cardia relieves dysphagia. Other treatments include endoscopic laser therapy for unresectable obstruction or bleeding lesions. Blood transfusion may be appropriate for symptomatic anaemia. The management of pain from gastric carcinoma follows established palliative care practice. Coeliac plexus nerve blocks may be effective. As with any malignant condition, the management of symptoms is multidisciplinary and is often led by palliative care and hospice based teams. View larger version: In this window In a new window Early gastric cancer. Top left: endoscopic appearance of cancer before dye spraying. Top right: the same lesion after spraying with 0.2% indigo carmine dye. Bottom left: lesion outlined by burn marks before excision. Bottom right: mucosal defect after removal of the lesion with 1 cm margin (blue colour is due to indigo carmine dye) Prognosis The disease is incurable in about half of patients at presentation. With regional lymph node metastases, five year survival after gastrectomy is about 10%. In those with only perigastric lymph node involvement survival rises to 30%, and in those with gastric carcinoma confined to the stomach five year survival is about 70%. Only 10% of patients with...