Adenocarcinoma Of The Stomach

Adenocarcinoma of the Stomach SENG Jingjing M.D. Department of General Surgery

Introduction • Tumours of the stomach Malignant ---great majority Benign -------rare

Malignant tumours

primary

• Gastric carcinoma • Lymphomas • Carcinoid tumour • Sarcoma

secondary

• Invasion from adjacent tumours(pancreas or colon)

Benign tumours • Gastric polyps • Leiomyomas

Gastric anatomy

• Cardia and pylori • Fundus ,body, antrum • Lesser curvature and greater curvature

The Blood Supply of the Stomach • • • • •

left gastric artery and vein right gastric artery and vein left gastroepiploic artery and vein right gastroepiploic artery and vein Short gastric artery and vein

EPIDEMIOLOGY

• Gastric cancer is the second most common cancer in the world ,surpassed only by lung cancer.

• Cancer of the stomach is rare before the age of 50 and increases in frequency thereafter.

• Males have one and a half times the risk of females.

• The disease is more common in low socio-economic groups.

Death Rate • • • • • • •

Costa rica Russia Japan Chile England Canada United states

RELATED FACTORS • • • • • •

Environmental factors Diet Helicobacter pylori and chronic gastritis Adenomatous polyps Previous gastric operation Other

Environmental Factors • The incidence of gastric cancer varies from country to country as well as regionally within countries.

• Studies of migrants from Japan to the United States ,the offspring appear to have the same risk as other Americans.

• In much of the western world, the incidence and death rates have steadily decreased in recent years.

• It suggests that environmental factors play an important role.

Diet

• Gastric cancer appears to be correlated with a high intake of preserved foods, (such as foods containing high levels of salt,nitrates,and nitrites ),pickled vegetables ,and salt

• Ascorbic acid and betacarotene in fresh fruits and vegetables act as antioxidants.---------Benefit foods ,they can decrease the incidence of gastric cancer.

Helicobacter Pylori and Chronic Gastritis • There is growing evidence that HP infection plays a role in the development of gastric cancer.

• The link between HP and gastric cancer is strengthened by the fact that HP infection causes more than 80% of chronic gastritis cases.

• In addition ,chronic HP infection, if untreated , usually leads to chronic atrophic gastritis with metaplasia ,with an associated high risk of gastric cancer.

Adenomatous Polyps • Adenomatous gastric polyps are rare but carry a distinct potential for the development of malignancy.

• Patients with multiple polyposis or multiple recurrent adenomas should be considered for subtotal or total gastrectomy.

Previous Gastric Operation

• There is considerable evidence that gastric surgery for benign conditions increases the risk of gastric cancer by twofold to sixfold.

• Most cases have occured after Billroth 2 anastomosis ,15 to 20 years after the original surgical procedure.

Molecular Genetics • The molecular and chromosomal alterations leading to the development of gastric adenocarcinoma

• Blood group A • Hereditary non-polyposis colon cancer syndrome (HNPCC) ,associated with an increased incidence of gastric as well as colon cancer

Pathology • Microscopic appearances In 1965, Lauren divided gastric cancers into intestinal and diffuse subtypes.

Pathology • This classification is still used internationally and has prognositic importance

Lauren’s Type

• Intestinal type• Diffuse type Cells grow in Cells are singular clumps and has and arranged in files and are histological features similar surrounded by a marked stromal to intestinal reaction. epithelium.

Macroscopic Pathology

• In 1926, Borrman proposed a gross classification of gastric cancer .

• The system is still used descriptively in the United Stated and is a more formal component of tumor staging in Japan.

Borrman’s Classification • Group 1 circumscribed ,solitary ,polypoid carcinomas without ulceration

Borrman’s Classification • Group 2 ulcerated carcinomas with walllike marginal elevation and sharply defined borders

Borrman’s Classification • Group 3 partially ulcerated carcinomas with marginal elevation and partial diffuse spread

Borrman’s Classification • Group 4 diffuse carcinoma

Morphological forms

• Fungating tumours • Malignant ulcers • Infiltrating carcinomas

• Linitis plastica the leather-bottle stomach

• Infiltrating carcinomas spreads widely beneath the mucosa and diffusely invades the muscular wall,this causes marked wall thickening and rigidity and the whole stomach contracts to a very small capacity ,and its appearance is likened to a leather bottle.

Staging • TNM Classification

Early Gastric Cancer Early gastric cancer is defined as disease involving the mucosa or submucosa,and as such may be fairly large .

Advanced Gastric Cancer • Advanced gastric cancer suggests invasion of the muscularis or beyond.

Symptoms and Diagnosis Symptoms are minimal until late in the course of the disease and patients most commonly present with advanced local and distant disease

• Symptoms may be produced by the local effects of the tumour ,by secondary deposits or by the general features of malignant disease.

Local symptoms

• Epigastric pain • Pain radiating into the back(suggesting pancreatic involvement)

Local symptoms • Vomiting,especially with a pyloric or antral tumour producing pyloric obstruction • Dysphagia in tumours of the cardia

Symptoms from secondaries

• The patient may first report with jaundice due to liver involvement or abdominal distension due to ascites

General features

Examination

• Local examination : a mass in the upper abdomen

• A search for secondaries : enlargement of the liver Virchow node palpable mass on pelvic examination

Virchow’s node

Enlarged ,hard left supraclavicular nodes

Invasion and Metastasis • Direct spread • Lymph node metastasis • Blood duct metastasis • Plant metastasis

Direct spread

Local spread is often well beyond the naked-eye limits of the tumour and the oesophagus or the first part of the duodenum may be infiltrated.Adjacent organs (pancreas,abdominal wall,liver,transverse mesocolon and transverse colon )may be directly invaded.A gastrocolic fistula may develop.

Lymphatic

• Lymph nodes along the lesser and greater curves are commonly involved.Lymph drainage from the cardiac end of the stomach may invade the mediastinal nodes and thence the supraclavicular nodes of Virchow on the left side .at the pyloric end ,involvement of the subpyloric and hepatic nodes may occur.

Blood stream

• Dissemination occurs via the portal vein to the liver and thence occasionally to the lungs and the skeletal system.

Trans-coelomic spread

• May produce peritoneal seedlings and bilateral Krukenberg Tumours due to implantation in both ovaries.

Krukenberg tumour • Gastric cancer sometimes spreads across the peritoneal cavity, particularly to the surface of the ovaries

Investigation

• Barium meal • Endoscopy and biopsy • CT scanning

• For metastatic disease, CT scanning is used most widely to assess the site and extent of metastases before embarking upon surgery

• It is useful for showing local tumour invasion , lymph node involvement and heptic metastase.

Differential diagnosis

• Carcinoma of the caecum • Carcinoma of the pancreas • Pernicious anaemia • uraemia

Treatment • Radical surgery offers the only prospect of cure even when the tumor is small.

Treatment

• The cure rate is determined by the stage of the disease at presentation.

Survival Rate • Survival results strongly support the view that early detection dramatically increases the chance of curative surgery.

Radical gastrectomy

• Early cancer 5-year survival 90%

• Advanced cancer 5-year survival <50%

Radical gastrectomy • Tumour • Resection margin:4-6cm • Lymph nodes :R0-R4 resection

Adjuvant therapy • Radiotherapy • Chemotherapy

Summary • Gastric cancer remains a devastating disease. • The 5-year survival in patients with resection of all gross disease and clear margins ranged from 20-38%.

Summary • The extended resection (R2)can be performed safely.

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