Pathophysiology Of Gastric Cancer f444

PATHOPHYSIOLOGY OF GASTRIC CANCER Etiology: Unknown

Precipitating Factors: - Diet/Nutrition: high fat, low fiber, undercooked/ charred foods - Stress - Bowel Habits - Lifestyle: smoking, alcoholism

Predisposing Factors: - Age: 40 y/o above - Heredity - Environment: exposure to carcinogens - Gender - Previous Gastric/ Colon/ Rectal Ca

Affects normal cells

proctooncogenesis

Mutation in the DNA mismatch repair genes

Activation of oncogenes

Negative effect on DNA repair

Tumor suppressors deactivates

Mutated cell multiplies Uncontrolled proliferation Cells grow and divide quickly

Polyposis collagen inactivates

DNA repair genes inactivates

Permits unchecked cellular replication

Cancer cells divide and proliferate

Increased cell division

A

B

C

A

B

Cancer cells undergo further mutation

Activation of oncogenes Prevents poptosis Increased lifespan of affected cells Replicates just like normal cells Increased number of malignant cells

C

Invades epithelia of GIT

Alters genetic make up of epithelium

Stem cell transformation

Lateral and downward spread of abnormal cells

Altered stem cell replicates

Replaces normal cells

Adenoma D

D

D

Extends to adjacent cells Adenocarcinoma

Extends downwards

Obstructs ageways

Extends to small intestines

Mass/ Tumor

Extends to anus Extends to rectum

Tumor bleeds Anorectal Mass

Affects adjacent structures

Hematochezia/ hemoptisis/ hematemesis Blood loss

Lymphatic spread Extends to vaginal wall

anemia pallor

bleeding

Foul smelling discharge

Invades/ compresses nerves Back/ pelvic pain

Bowel obstruction

Abdominal pain

Change in bowel habbits Loss/ decreased bowel movements Retention of fecal matter sepsis