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04-24-2008, 08:51 AM
@ PREDISPOSING FACTORS
m Age: Commonest between 40 & 60 years.
mSex: male > female
m Site: 60% in the pyloric antrum. 30% in the body.
5% in the cardia. 5% diffuse.
m Precancerous Conditions:
1) Gastric polyps.
2) Chronic gastritis (Atrophic gastritis)
3) Chronic gastric ulcer.
4) Pernicious anaemia.
5) Achlorhydra. 6) Blood group A.
The molecular pathology of gastric cancer showed that:
H-ras onchogen mutation occurs at an early stage of gastric carcinogenesis but its role in tumour progression is not clear.
c-erb B2 may be important in tumour progression.
@PATHOLOGY
ŒMacroscopic appearance:
There are several classifications of gastric carcinoma.
a) According to Lauren (DIO) classification:
Three types of cancer stomach are encountered
1) Intestinal type: on top of intestinal metaplasia of gastric mucosa. It gives ulcer or mass.
2) Diffuse type: Infiltrate gastric wall and arise from apparently normal mucosa.
3) Other: 10% of cases are mixed of both above types.
b) According to extension in wall:
·The gastric cancer can be divided into early and advanced cancer according to invasion of the wall.
·The early gastric cancer is defined as cancer limited to mucosa and submucosa and of three endoscopic appearances: Type I (Protruding), Type II (Superficial) andType III (excavated). The superficial type shows 3 varieties. (See the figure)
·The advanced gastric cancer has 4 types (see the figure).
Ä Type I (Nodular invading musculosa), Type II (Excavating invading musculosa), Type III (Resting on serosa) & Type IV (Invading Serosa).



Protruding

Type I




Elevated

IIa
Flat Superficial



depressed

Type II IIb


IIc

Excavated



Type III




Morphological types of early gastric cancer


Type 1
Nadular
Invading
Musculosa

Type 2
Excavating
Invading musculosa

Type 3
Resting
on serosa

Type 4
Invading
Serosa Morphological types of
advanced gastric cancer

Microscopic appearance:
q Adenocarcinoma, with different grades of differentiation.
q Mucoid (Colloid) carcinoma = mucoid degeneration in cells of any type of carcinoma. The mucoid material in the cells pushes the nucleus to one side ® Signet-ring appearance
ŽStaging of gastric cancer:
There are several staging systems. Recently, an international staging system has been agreed. (TNM Categories).
 Prognosis:
The important prognostic factors in patients without distant metastases are:
1. Depth of invasion of the stomach wall by the tumour and lymph node spread.
2. Type of cancer (Intestinal or Diffuse)
3. Site of cancer (Cardia has the worst prognosis)
4. Degree of differentiation.
mSpread:
1- Direct spread: submucous 1 inch beyond the visible margin.
2- Lymphatic spread: Extensive in most cases. According to location of the tumor the tumor pass to the nearest group of lymph nodes.
TNM staging classify nodal involvement to:
N0 No lymph node metastases.
N1 Metastases in epigastric nodes.
N2 Metastases in nodes along main arterial trunks.
3- Blood spread: mainly to the liver, lung, bones and brain rarely have metastasis.
4- Spread through the peritoneal cavity: ®Krukenburg's tumor in the ovary, deposits in rectovesical pouch. (P/R examination ® rectal shelf), and malignant ascitis.
m Cl. picture:
Clinical groups:
a- The "New dyspepsia", after 40 years old, vague but persistent occurring in a patient who has never previously had "stomach trouble".
b- Insidious onset- 3A ® Anorexia ® Athenia® Anaemia
c- The obstructive type: At the cardia ® dysphagia.


At the pylorus ® pyloric obstruction.

d- Lump in the epigastrium is sometimes the cause of the patient seeking advice & In 30% of cases can be palpated.
e- Silent: Discovered after distant metastases e.g.
- liver 2rise or L.N. in porta hepatis with obstructive jaundice .
- Kruckenberg's tumor.
- Trousseau's sign (phlebitis migrans ).
- Troisier's sign .( Left supraclavicular L.N. enlargement.)
m Investigations:
Any patient above 45 years who develops anorexia should be considered to have cancer stomach until diagnosed otherwise."
1- Fiberoptic gastroscopy: Detect small early lesions and biopsy can confirm diagnosis.
2- Exfoliative cytology: make correct diagnosis in 90% of cases.
3- Barium meal: may show:
a- Irregular filling defect. b- Narrowing of the pyloric antrum.
c- Big ulcer outside ulcer bearing area.
4- Gastric function tests: Achlarohydra.


m Treatment:
The Japanese Research Society for Gastric Cancer has issued a classification of gastric resection for cancer based on the radicality (R) of the procedure.
R1: The lymph node clearance is confined to the primary groups i.e. around gastric wall (Practically this can be acheived by removal of omenta)
R2: Necessiates clearance of the lymph nodes around coeliac trunk and its branches and their branches.
R3: Extends the node clearance to the nodes present in porta hepatis, behind the pancreas in the root of the mesentery, around the middle colic vessels and para-aortic lymph nodes. On occasions this will involve partial colectomy, hepatic lobectomy, subtotal pancreatectomy and even pancreaticoduodenectomy.
A gastrectomy does not need to be total to be curative. 2 cm margin for early cancer or 5 cm for advanced cancer is adequate.
Total gastrectomy is necessary for the following:
1. Tumours of the cardia.
2. When the tumour involve two or all three sectors of the stomach.
3. In diffuse carcinoma irrespective of size.
An absolute curative resection for cancer stomach may be deemed to have been performed when:
1. There is no peritoneal or hepatic deposits.
2. There is no serosal involvement.
3. R (Resection level) exceeds the level of nodal involvement (N).
i.e. R > N.
When R level = N value the resection is classified as relative curative.
When R<N it is considered as incurable case & managed as follow:
1- If resectable: do palliative gastrectomy.
2- If irresectable:
A- Non obstructive: Radio-therapy and chemotherapy to relive the pain
B- Obstructive:
Pyloric obstruction Cardiac obstruction
SOURCE: DR. AYMAN SALEM'S BOOK
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