Malignant Tumors of the Colon
Carcinoma of Colon
-Most common CA of the GIT
-Older age grp; peak incidence 80 years
-male ( > rectum) ; female ( > colon)
Etiology:
1. Unknown
2. Hereditary
3. Diet --> low fiber diet and high animal fat
-Distribution --> shifting to the right side
Risk Factors for Colorectal CA
1. Aging is the dominant risk factor w/ rising incidence after 50 y/o.
2. Hereditary risk factor:
80% colorectal are sporadic
20% w/ known family hx.
3. Dietary factors:
High animal fat(saturated or polyunsaturated fats), but oleic acid (coconut & fish
oil does not).
Vegetable fiber, Ca, selenium, Vits. A, C, & E are protective
Alcohol increase colonic CA
4. Obesity and sedentary lifestyle contributory
5. Smoking increased the incidence
Premalignant Diseases of Colon & Rectum
1. Adenoma
2. Familial adenomatous polyposis syndrome
3. Gardner’s syndrome
1
, 4. Hamartomas(familial juvenile polyposiscoli & Peutz-Jegher polyp)
5. Inflammatory bowel disease
a. Ulcerative colitis
b. Crohn’s disease
6. Schistosomiasis (Billharziasis) –S. mansoni & S. japonicum
Genetic Defects for Colorectal CA
Mutation may cause:
1. Activation of: K-ras (an oncogene)
2. Inactivation of tumor-suppressor gene:
-APC
-DCC (deleted in colorectal carcinoma)
-p53
Adenoma to Carcinoma Pathway
2
Carcinoma of Colon
-Most common CA of the GIT
-Older age grp; peak incidence 80 years
-male ( > rectum) ; female ( > colon)
Etiology:
1. Unknown
2. Hereditary
3. Diet --> low fiber diet and high animal fat
-Distribution --> shifting to the right side
Risk Factors for Colorectal CA
1. Aging is the dominant risk factor w/ rising incidence after 50 y/o.
2. Hereditary risk factor:
80% colorectal are sporadic
20% w/ known family hx.
3. Dietary factors:
High animal fat(saturated or polyunsaturated fats), but oleic acid (coconut & fish
oil does not).
Vegetable fiber, Ca, selenium, Vits. A, C, & E are protective
Alcohol increase colonic CA
4. Obesity and sedentary lifestyle contributory
5. Smoking increased the incidence
Premalignant Diseases of Colon & Rectum
1. Adenoma
2. Familial adenomatous polyposis syndrome
3. Gardner’s syndrome
1
, 4. Hamartomas(familial juvenile polyposiscoli & Peutz-Jegher polyp)
5. Inflammatory bowel disease
a. Ulcerative colitis
b. Crohn’s disease
6. Schistosomiasis (Billharziasis) –S. mansoni & S. japonicum
Genetic Defects for Colorectal CA
Mutation may cause:
1. Activation of: K-ras (an oncogene)
2. Inactivation of tumor-suppressor gene:
-APC
-DCC (deleted in colorectal carcinoma)
-p53
Adenoma to Carcinoma Pathway
2
