June 23, 2024

Colorectal cancer (CRC) or cancer of the large intestines and the rectum is the third most commonly diagnosed cancer in males and the second in females worldwide. CRCs are currently also the third leading malignancies in the Philippines. It has a high mortality rate when diagnosed late in its course but it can be prevented or cured when detected at an early stage. 

Colorectal cancer may present with:

1. No signs or symptoms. The illness is diagnosed during a regular or routine checkup.

2. Signs and symptoms like change in bowel habits, constipation, diarrhea, weight loss, loss of appetite.

3. Nausea, vomiting, abdominal pain, abdominal distention and other signs or symptoms of intestinal obstruction.

4. Blood in the stools – termed melena (dark stools) or hematochezia (bloody stools).  Low blood pressure due to sudden tumor bleed. 

5. Unexplained anemia

6. Mass in the rectum or abdomen

7. Other signs and symptoms may be related to adjacent organs invaded by the tumor. For example when the tumor invades the urinary bladder then the patient may present with an unusual sign like bloody urine. 

Screening tests help identify CRCs at an early stage. Abnormal or precancerous new growths can also be identified and removed before they become cancerous. Current guidelines state that CRC screening should be done at age 50 years old, but if a person has a strong family history for cancer and is at high risk, then screening may be started at age 45 years.

Screening tests include simple stool examination to test for occult blood (not easily visible to the eye), colonoscopy or sigmoidoscopy. CT scan (CT colonography) is also done in other centers. Precancerous lesions – adenomas or adenomatous polyps can be detected and removed with these tests especially colonoscopic examinations. In most cases, adenomas or adenomatous polyps can progress to cancer in at least 10 years. The risk for CRC can be reduced by 90 percent with regular screening and removal of polyps if present. 

Risk factors include: 

Hereditary or genetic familial syndromes like familial adenomatous polyposis, Lynch syndrome, Peutz-Jeghers syndrome, and hamartomatous polyposis.

Positive family history for CRC in a parent, sibling, or child. History of adenomatous polyps or adenomas in other relatives especially if many are affected, and if lesions occurred at younger age. 

Ulcerative colitis and Chrohn Disease – these are inflammatory diseases.

Lifestyle factors that increase risk: cigarette smoking, obesity, low fiber high fat, high red meat diet; lack of exercise; alcohol consumption.

Preventive measures include lifestyle modifications. Aspirin has been shown to help prevent CRC but since it has side effects like stomach irritation and increased risk for bleeding, its use should be supervised by a physician. 

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