Colon cancer should not be confused with rectal cancer. However, the two diseases often develop simultaneously. Colon cancer is caused by the uncontrolled growth of unhealthy cells in the large intestine. Most forms of colon cancer started as small benign adenomatous polyps (noncancerous tumors) on the large intestine's inner walls. Over time, the polyps can become malignant if not removed from the lining of the intestines during a colonoscopy procedure. Malignancy occurs when damage colon cancer cells invade healthy tissue surrounding the tumor causing significant damage and complications.
Without treatment including the removal of the polyp, the malignant tumor can metastasize, causing cancerous cells to break away from the tumor and spread to other sites in the body. The cancer cell growth can invade and destroy healthy tissue. Metastasis at distant sites can be extremely difficult to treat.
- Colon Cancer Causes
- Who Gets Colon Cancer?
- Colon Cancer Symptoms
- Diagnosing through Routine Screening
- Treating Colon Cancer
Colon Cancer Causes
The lifespan of typically healthy colon tissue involves growing, dividing, and eventually dying to make way for the growth of new tissue. Cancer is often the result of uncontrollable growth and a reprogramming of apoptosis (cell death) that can break down the potential of cancer overrunning the body. When the colon cell does not die as designed, it continues to grow and divide, reproducing new cells with the same abnormality. Even though scientists have yet to determine the exact cause of why abnormal cells change their behavior they have determined potential risk factors for the development of colon cancer that includes:
- Polyps – Most colon cancer cases began with precancerous polyps in the large intestine that eventually developed into malignant (cancerous) cells like:
- Adenomas that are typically removed during a colonoscopy procedure
- Inflammatory Polyps that usually develop from colitis (colon inflammation)
- Hypoplastic Polyps that become cancerous in rare cases
- Genetic Abnormalities – If the colon cell's DNA is mutated or becomes damaged, it can cause uncontrollable growth through cell division. The mutated cells lack the ability to correct the damaged DNA by not allowing the cell to die off naturally causing uncontrollable cell growth and eventual development of the tumor.
- Genetic Predisposition – Inheriting mutated genes from parents, grandparents and ancestors often increase the individual's potential risk of developing cancer at some point in the aging process.
- Traits and Lifestyle Choices – Traits, environmental exposure, and lifestyle choices are essential risk factors for the development of colon cancer, especially in individuals who are 50 years and older. Colon cancer usually develops in older individuals living a sedentary lifestyle and those who smoke tobacco or eat excessively (obesity). Scientists have found a correlation between consuming Western diets and the increased potential of developing colon cancer.
- Medical Conditions – The risk of developing colon cancer has been associated with many conditions in diseases including diabetes, cancer radiation treatment, Crohn's disease, ulcerative colitis, and growth hormone disorder (acromegaly).
Who Gets Colon Cancer?
In the United States, more than 140,000 individuals are diagnosed with colon cancer every year, where more than 50,000 men and women die from the condition annually. Those greatest at risk for developing colon cancer tend to be split equally between women and men of the same age. However, African-American men and women have a higher potential risk for developing colon cancer and dying from the condition compared to Caucasians (white) men and women of the same age. In addition, those who are obese or overweight have increased the potential of developing colon cancer, especially in men.
Individuals with a genetic predisposition (inherited familial gene) have an increased chance of developing deadly cancer, especially those with a first-degree relative (parent, child, or sibling) and those with a secondary relative (grandparent, uncle, aunt, nephew, niece, or half-sibling) who has had colon cancer.
Also, individuals who had been diagnosed with ulcerative colitis, Crohn's disease, or precancerous polyps at a higher risk of developing colon cancer. This is because many of these conditions cause the colon to inflame. Doctors and scientists have yet to determine the most effective way of preventing the development of colon cancer. However, lifestyle choices including consuming too much fat and too little fiber along with drinking excessive alcohol, smoking and not exercising likely plays an important role in reducing the chances of avoiding the development of deadly cancer.
Colon Cancer Symptoms
The most common symptoms involving colon cancer vary greatly between patients. Most symptoms are determined by the location of the disease, areas where it has spread, and the size of the tumor. Common colon cancer symptoms in the early stages of the disease include:
- Constipation or Diarrhea
- Narrow Stools
- Inconsistent stool changes
- Bloody stools
- Rectal bleeding
- Fatigue or weakness
- Constant bowel movement urges
- Pain when defecating
- Unexplained weight loss
- Anemia (iron deficiency)
- IBS (irritable bowel syndrome)
Without proper treatment, the colon cancer can easily metastasize (spread) to other areas of the body causing additional symptoms.
Diagnosing through Routine Screening
Any individual can lower the potential risk of the disease through colon cancer screening, especially when done regularly between 50 and 75 years of age. The doctor will perform a high-sensitivity FOB (fecal occult blood) test using stool samples to detect the presence of cancerous cells. The doctor will also likely recommend a colonoscopy, an expensive procedure performed under anesthesia to detect and remove polyps when found. Some patients undergo a flexible sigmoidoscopy that identifies polyps in the intestines but does not remove them.Staging Colon Cancer
In addition to diagnosing colon cancer, the doctor will likely stage the disease through testing to determine the extent of the cancer and if it has spread throughout the intestines or to other distant sites. These stages include:
- Stage I – cancer has grown uncontrollably affecting the mucosa (superficial lining) of the large intestine but has yet to metastasize beyond the rectum or intestine wall.
- Stage II – The cancer has progressed to the point where it is spread through the wall of the rectum or colon and possibly into the neighboring lymph nodes.
- Stage III – The colon cancer has now invaded neighboring lymph nodes but has yet to metastasize to other distant sites.
- Stage IV – The cancerous cells have metastasized to other areas of the body including other organs like the lung, liver, or brain.
Treating Colon Cancer
Doctors have a variety of options when treating colon cancer and colorectal cancer. However, the recommended treatment is often dependent on the location and size of the tumor and if the cancer is spread to other areas of the body. Typical treatments for colon cancer involve radiation, chemotherapy, and dissection.
- Surgical Options – A surgeon can surgically remove a portion of the colon (colectomy) or dissect the lymph node.
- Medication Options include chemotherapy and chemotherapy protective medications. Chemotherapy destroys cancerous cells that are growing uncontrollably and developing a tumor. Chemotherapy protective medications reduce many of the side effects and adverse reactions caused by chemotherapy treatments.
These treatments are typically performed by oncologists (cancer specialists) gastroenterologists (specialists in the digestive system and G.I. tract disorders) and surgeons who operate on the affected area. Sometimes, the surgeon is required to perform a temporary or permanent colostomy to allow waste to leave the body through an incision made in the abdominal wall.