Colon cancer, also known as colorectal cancer, is one of the most common cancers worldwide. It develops in the large intestine (colon) or the rectum and often starts as small, benign growths called polyps, which can become cancerous over time.
Understanding the causes, symptoms, risk factors, and screening options is crucial for early detection, as colon cancer is highly treatable when caught early. This article will cover:
The causes, symptoms, and risk factors of colon cancer
The importance of screening and when to get tested
The available treatment options for patients diagnosed with colon cancer
Colon Cancer 101: Causes, Symptoms, and Risk Factors
What Causes Colon Cancer?
Colon cancer develops when abnormal cells in the colon or rectum grow uncontrollably. While the exact cause varies, several key factors contribute to its development:
Genetic Mutations
- Some people inherit gene mutations that increase their risk of colon cancer, such as Lynch syndrome or familial adenomatous polyposis (FAP).
- These mutations affect cell growth and prevent the body from repairing damaged DNA, leading to cancer.
Uncontrolled Polyp Growth
- Most colon cancers start as polyps, which are small growths in the colon lining.
- While not all polyps turn cancerous, certain types (adenomatous polyps) have a higher risk of developing into cancer.
Chronic Inflammation
- Conditions like ulcerative colitis and Crohn’s disease increase colon cancer risk by causing chronic inflammation in the intestines.
Poor Diet and Lifestyle Choices
- A low-fiber, high-fat diet (rich in red and processed meats) increases the likelihood of colon cancer.
- Lack of fiber slows digestion, allowing harmful substances to stay in the colon longer, increasing exposure to carcinogens.
- Obesity, smoking, and heavy alcohol consumption further elevate risk.
Symptoms of Colon Cancer
Colon cancer symptoms often do not appear in the early stages, making regular screening crucial. When symptoms do develop, they may include:
- Changes in Bowel Habits: Persistent diarrhea, constipation, or narrow stools
- Rectal Bleeding: Blood in the stool, which may appear dark or bright red
- Unexplained Weight Loss: Losing weight without a change in diet or exercise
- Abdominal Discomfort: Cramping, bloating, or persistent pain
- Fatigue and Weakness: A result of anemia due to hidden blood loss in the stool
If you experience any of these persistent symptoms, consult a doctor immediately for evaluation.
Who is at Risk?
Several factors increase the likelihood of developing colon cancer:
1. Age:
- Colon cancer is more common in individuals over 45, although younger cases are rising.
2. Family History:
- Having a first-degree relative (parent, sibling, or child) with colon cancer increases the risk.
- If multiple family members have had colorectal cancer, genetic testing may be recommended.
3. Personal Medical History
- Previous colon polyps or a past diagnosis of colon cancer raises the risk of recurrence.
4. Sedentary Lifestyle
- Lack of physical activity is linked to a higher risk of colon cancer. Exercise helps regulate digestion and reduces inflammation.
5. Type 2 Diabetes and Insulin Resistance
- People with diabetes have an increased risk of developing colorectal cancer due to high insulin levels, which may promote tumor growth.
Early detection through screening is the best way to prevent colon cancer or catch it at an early stage when treatment is most effective.
Colon Cancer Screening: When and Why You Should Get Tested
Why is Screening Important?
Colon cancer screening detects precancerous polyps or early-stage cancer before symptoms appear. When caught early, colon cancer has a 5-year survival rate of over 90%.
Who Should Get Screened?
- Average Risk: Adults 45 and older should begin routine colon cancer screening.
- High Risk: Individuals with a family history, genetic predisposition, or inflammatory bowel disease (IBD) may need screening earlier and more frequently.
Types of Colon Cancer Screening Tests
1. Colonoscopy (Gold Standard)
- A thin, flexible tube with a camera is inserted into the colon to look for polyps or cancer.
- If polyps are found, they can be removed immediately to prevent cancer.
- Recommended every 10 years for those at average risk.
2. Fecal Occult Blood Test (FOBT) and Fecal Immunochemical Test (FIT)
- These tests check for hidden blood in stool, a possible sign of colon cancer.
- Should be done annually.
- A positive result requires a follow-up colonoscopy.
3. CT Colonography (Virtual Colonoscopy)
- Uses X-rays and a computer to create a 3D image of the colon.
- Less invasive but requires a follow-up colonoscopy if abnormalities are found.
4. Stool DNA Test (Cologuard®)
- Detects abnormal DNA in stool that may indicate colon cancer.
- Recommended every 3 years for those at average risk.
When to Stop Screening?
- If you are 75 or older, talk to your doctor about whether continued screening is necessary based on your overall health.
Treatment Options for Colon Cancer: What You Need to Know
If colon cancer is detected, treatment options depend on the stage of cancer, overall health, and tumor location.
1. Surgery (Primary Treatment for Early-Stage Cancer)
Surgical removal of cancerous tissue is often the first line of treatment.
- Polypectomy: If cancer is detected inside a polyp, it can be removed during a colonoscopy.
- Colectomy (Partial or Total): If the cancer is larger, part of the colon may need to be removed.
- Lymph Node Removal: Nearby lymph nodes are often removed to prevent cancer spread.
2. Chemotherapy
- Used after surgery to kill remaining cancer cells and prevent recurrence.
- Common drugs: Fluorouracil (5-FU), Oxaliplatin, Capecitabine.
- Given in cycles, often lasting several months.
3. Radiation Therapy
- High-energy rays target and destroy cancer cells.
- Typically used for rectal cancer or advanced colon cancer that cannot be fully removed surgically.
4. Targeted Therapy
- Drugs like Bevacizumab (Avastin) and Cetuximab (Erbitux) target specific cancer growth factors.
- Often used in advanced-stage colon cancer alongside chemotherapy.
5. Immunotherapy
- Checkpoint inhibitors (like Pembrolizumab) help the immune system attack cancer cells.
- Works best in patients with genetic mutations like MSI-H or Lynch syndrome.
6. Palliative Care for Advanced Cancer
- If cancer has spread to other organs (Stage IV), treatment focuses on slowing growth and relieving symptoms.
- A combination of surgery, chemotherapy, and pain management can improve quality of life.
Source: https://www.gastrodoxs.com/blog/whos-at ... lon-cancer