CARCINOMA OF THE STOMACH

Second commonest tumor of gastro – Intestinal tract

Etiology:

• Environment : the higher incidence of gastric cancer in urban than in rural countries suggests that a carcinogenic which may be ingested or inhaled is a probable etiological factor.

• Diet: Ingested carcinogens seem to be important:

a)3.4 benzpyrene contained in smoked meat & fish are carcinogenic

hydrocarbons explaining the highest incidence of cancer stomach in

japan.

b) Substances that cause irritative gastritis such as spirits.

• Heredity: The role of heredity is suggested by the higher incidence of the disease among the relatives of patients with gastric cancer & in subjects of blood groupA.

• Achlorhydria: About 2/3 of patients with gastric cancer have achlorhydria.

• Atrophic Gastritis.

• Pre – malignant conditions:

Adenomatous polyps.

Atrophic gastritis.

Ch GU.

Pathology:

• Site: The commonest site is the prepyloric region (64% ).

• N/E:

1. Polypoid or Fungating: This type is commonest in the body & fundus where it forms a bulky polypoid mass projecting into the lumen. It is liable to undergo ulceration & necrosis with hemorrhage & infection.

2.Malignant Ulcer: this is the most malignant type & occurs most frequently in the pyloric region & in the region of the curvatures.

3.Infiltrating: This type usually starts in the pyloric region & infiltrates all layers diffusely. "Linitis plastica" (Leather bottle stomach) is a variety of this type in which the whole stomach is converted by diffuse fibrosis into a narrow tube.

• Histopathology

1-Adenocarcinoma (95%): According to the arrangement of cells:

a) Columnar cell adenocarcinoma: the cells are arranged in acini.

b) Spheroidal cell adenocarcinoma: the cells become rounded due to mutual pressure. It is less differentiated than columnar cell adenocarcinoma.

c) Colloid carcinoma: It is an adenocarcinoma with plenty of mucin in the cells, acini & tissue spaces.

2-Squamous cell carcinoma: It is due to spread from carcinoma of the esophagus & affects the cardia & the fundus

Spread:

1)Direct:• In the wall of the stomach: Microscopical

spread is 5 cm beyond the palpable edge of tumor. Direct spread of pyloric growth infiltrates the duodenum, while the fundal growth invades the lower esophagus.

• Extragastric spread: To liver, pancreas, transverse colon, mesocolon &less often spleen. Jejunum & diaphragm.

2)Lymphatic: Both by embolization & permeation lymphatic drainage of the stomach.

3 Blood: To the liver via the portal vein is common but spread via the systemic circulation to the lungs, bones & other organs is usual & late

3) Transperitoneal: when the primary tumor reaches the serous surface, cells set free in the peritoneal cavity may produce malignant ascites with multiple nodules on the omentum, parietal peritoneum & serous surfaces of the abdominal organs

- Invasion of the pelvic cul-de-sac produces a hard metastatic mass, referred to as a rectal or Blum shelf.

- If females, the cells may implant on the ovaries, giving rise to bulky tumors (Krukenbergs tumor)

Why is the overies specilly affected?

(1) The peritoneal covering of the ovaries is partially denuded monthly during ovulation forming a raw area.

(2) Retrograde lymphatic permeation, especially from a carcinoma of the colon

Complicalions:

1-Bleeding

2-Obstruction of the pylorus or the esophagus.

3-Perforation

4-Cachexia.

Clinical Picture:

This is a very difficult disease to diagnose early not only because of the diversity of its presentation but also because of the time lag between the commencement of the growth & the appearance of symptoms

(1)Dyspepsia group: Old males with pain vomiting, loss of

periodicity & not relieved by drugs.(2) Insidious onset Weakness with the three

As Anemia, Anorexia and Asthenia.(3) The obstructive types : Carcinoma of the cardia presents

with dysphagia Carcinoma of the pylorus with

fullness, belching and then vomiting (4) Lump In 30% of cases

(5) Silent Carcinoma of the body of the stomach

may be silent but give rise to features in other organs, such as obstructive jaundice due to secondary deposits in the liver ascites from carcinomatosis of the peritoneum Krukenbergs tumor etc..

Differential Diagnosis:(I) Vague dyspeptic symptoms From other

causes of dyspepsia.(2) Obstructive type: - Pyloric obstruction due to cancer

pylorus has to be differentiated from that due to stenosing duodenal ulcer by the long duration & the hugely dilated stomach in the latter.

-Obstruction at the cardia has to be differentiated from other causes of dysphagia

(3) Mass type Cases presenting as masses in the epigastrium with minimal symptoms related to the stomach have to be differentiated from other masses in the epigastrium .

(4) Ulcer type seen by gastroscopy has to be differentiatod from chronic gastric ulcer

Investigations:A. Laborotory:

(1) Occult blood stools is always positive.

(2) Blood examination for anemia and its type e.g. pernicious.

(3)Gastric function tests: the majority have either achlorhydria or hypochlorhydria

B. Radiological :

Barium meal: 90% accuracy in expert hands.

a. Irregular filling defect in pyloric antrum or body of stomach.

b. Large ulcer niche outside the ulcer bearing area. c. Linitis Plastica: Narrowed rigid distorted

d. Pyloric obstruction, with minimal proximal dilatation

e. Carman's Meniscus: Crescentic barium shadow around the elevated edge.

C. Gastroscopy:

Mulliple biopsies are essential

Exfoliative cytology confirm the diagnosis in doubtful cases in about 70% of cases

Endoscopy can detect carcinoma in an earlier stage than the radiological methods.

Prognosis:

Cancer stomach has very bad prognosis

• 50% Of Patients are inoperable when first seen of these 50 % are inoperable at operation

• Only 5-10% of the total number survive 5 years

Operative Treatment

(A) Exploration

• The First step in the operation is to determine position & extent of the growth & the degree of fixation to surrounding structures

• The regional lymph noadesin the lesser & greater omenta of the hilum of the spleen and the lesser sac are next examined

• The liver is inspected and palpated for the presence of secondries

• The peritoneum, the retrovesical pouch & pelvic viscera are then examined for fluid & malignant deposits

(B) Procedures:

* Curable

Excision of the tumor en block with at least 3 inches of grossly normal tissure one it her side of the growth. with the draining lymph nodes

• (1) Carcinoma of the pylorus & Antrum (lower Radical (Abdominal approach) .

• Resection of 85% of the stomach• Distal cut lie I inch beyond the pyloric vein

of Mayo to remove the Supra infra & retropyloric lymph nodes

• Excision of both greater & lesscr omentum

• The operation is then completed by Billroth II anastomosis.

(2) Carcinoma of Body & Diffuse Carcinoma (middle 1/3): Total Radical gastrectomy Abdominal approach

a .Removal of all the stomach with greater & lesser omentum

b. The operation is then completed by oesophago-jejunostomy(Roux En- Y)

(3) Carcinoma of the Fundus & Cardia (upper 1/3) Radical oesophago-gastrectomy (Thoraco.abdominal approach) .

In the recent years there has been considerable emphasis on removing not only the lymph nodes adjacent the gastric wall ( R1) but also removing the retropancreatic nodes (R2 &R3 ) There is some evidence that extended form of curative resection may improve long term survival

Some surgeons have advocated splenectomy & tail pancreatectomy to remove pancreatico lineal lymph nodes if enlarged

Palliative procedures:

Whenever feasible , a limited resection should be carried out otherwise a bypass

procedure is perfomed

Criteria of inoperability :

(1) Nodules in Douglas pouch Krukenberg tumor does not itself make the case inoperable.

(2) Troisier's sign (enlarged left supraclavicular Lymph node ).

(3) Umbilical nodules.

(4) Diffuse lover secondaries.

(5) Malignant ascites.

(6) At operation unresectable tumor or lymph node due to infiltration of the portal vein or other vital structures e.g. pancreas, posterior abdominal wall & mesenteric vessels.

Pracedures :

(I) Carcinoma of the pylorus

a. Palliative subtotal gastrectomy. b.Anterior gastro-jejunostomy. To bypass obstruction.

(2) Carcinoma of Body Palliative subtotal gastrectomy

(3) Diffuse carcinoma: Feeding jejunostomy

(4) Carcinoma of the cardia:

Introduction of plastic tube.

Feeding gastrostomy.

Colon bypass.

Esophagojejunostomy.