Colon (Bowel) Cancer: Symptoms and Treatment

Colon, or colorectal cancer, is the third most common cancer and ranks third among cancer-related causes of death in both men and women. However, it is one of the most treatable cancers when diagnosed and treated in its early stages. The five-year survival rate for those diagnosed and treated at an early stage is 90%. In some cases, regular screening can detect potential precancerous formations, thus preventing cancer from developing in the first place.

The colon is a tube-shaped organ that makes up approximately 1.5 to 2 meters of the intestine. The colon and rectum together comprise the entire large intestine. The rectum is a short area that forms the last part of the intestine, where stool is stored. The digested food from the small intestine enters the colon, where any remaining nutrients are absorbed. The waste material then moves to the rectum, where it waits to be expelled. Colon cancer begins in the cells of the colon and can sometimes develop into polyps. If detected early and without spreading, it is a treatable condition; however, in cases where early diagnosis is not made, it typically manifests as a disease that shows spread in the colon wall. Once the spread within the colon is complete, metastasis, or the spread to different organs and tissues, can occur. Colon cancer can particularly progress to vital organs such as the lungs and liver through lymph nodes and blood vessels.

What are the Symptoms of Colon (Bowel) Cancer?

In colon cancer, changes in bowel habits are commonly observed. Because it presents symptoms, it can be easier to notice than many other types of cancer. Although the symptoms are related to bowel movements, the colon is a long organ, and conditions affecting its left and right portions can present different symptoms. The colon narrows further on the left side, which can lead to thinner stools, bleeding during bowel movements, changes in bowel habits, etc. The right side, being relatively wider, may present symptoms later, making early diagnosis more challenging. However, common symptoms include:

• A feeling that the bowel has not completely emptied, even after a bowel movement
• Changes in bowel habits (diarrhea, constipation)
• Bleeding or seeing blood in the stool
• Pain during bowel movements
• Presence of a clear discharge in the stool
• Abdominal pain and bloating

These symptoms can be observed early on and are easily noticed by the patient. Following these symptoms, indirect signs such as weight loss, decreased blood values and anemia, formation of abdominal masses, and increased pain due to possible bowel obstruction in advanced stages can also be seen. For early diagnosis, patients need to be aware of their bowel habits and monitor their normal patterns.

What Causes Colon (Bowel) Cancer?

Genetic factors are a significant cause of colon cancer, as with many other types of cancer. If there is a family history of colon cancer, the risk increases. Age is also a contributing factor, particularly in men aged 50-60, where more cases of involvement have been observed. Polyps that initially form benignly in a person’s bowel can sometimes develop into cancer. Polyps are tiny protrusions that form within the intestine. If these protrusions are detected, it is beneficial to monitor them.

Changes in genes are also known to increase the risk of developing this cancer. In some cases, the patient may have an underlying chronic bowel disease. Conditions like inflammatory bowel disease and ulcerative colitis can affect the inner lining of the colon and may act as triggers for colon cancer in certain instances. Lifestyle factors, such as smoking and unhealthy eating habits, can also be counted among the causes of colon cancer.

What are the Stages of Colon (Bowel) Cancer?

Although the stages of colon cancer are not distinctly separated, they are generally divided into about five stages to determine the treatment. Symptoms vary at these stages and provide information about the extent of the spread.

• Stage 0: This is the earliest stage of colon cancer. In this stage, polyps that have been diagnosed early can be removed and monitored, allowing the disease to be managed. No cancer treatment, such as chemotherapy, is required at this stage.
• Stage 1: In this stage, colon involvement is evident. A portion of the colon may need to be removed. Since there may be a spread to lymphatic tissues, these may also be removed in some cases.
• Stage 2: This stage indicates that there is spread outside the colon, but no distant tissue involvement is visible yet. In this stage, a significant portion of the colon and lymph nodes are removed. Chemotherapy is recommended for patients at high risk of recurrence.
• Stage 3: In the third stage, cancer has spread to the lymph nodes. The spread is rapid at this stage. The involved tissues are surgically removed, and chemotherapy is administered.
• Stage 4: In the final stage of cancer, spread is observed in distant tissues and organs, and the patient’s condition worsens. Surgical operation is generally not preferred, and treatments such as chemotherapy and radiation therapy are tried. After these treatments, a reduction in cancerous cells is expected. If a desired level of reduction is achieved and it is determined that the patient can withstand surgery, an operation may be planned.

How is Colon (Bowel) Cancer Diagnosed?

Colonoscopy, an endoscopic method, is most commonly used in cancer diagnosis. It is generally easier compared to other methods. During a colonoscopy, if polyps have formed, they can also be removed, providing a form of treatment. A stool sample is usually requested from the patient, and necessary examinations are conducted on the stool. Samples taken during the endoscopy are examined pathologically. In some cases, a computerized tomography scan may also be requested. MR-PET scans can also be requested at this time.

How is Colon (Bowel) Cancer Treated?

The treatment protocol for colon cancer generally aims to enhance the patient's lifespan and quality of life. Polyps with the potential to develop into cancer are usually removed during the initial colonoscopy. Surgical treatment is mandatory in the early stages. Tumorous parts are excised. If cancer has metastasized through lymphatic and vascular pathways, treatments such as chemotherapy are expected to reduce the tumor. In recent years, advances in technology have increased the life expectancy for patients with colon cancer and improved treatment opportunities. Some treatment methods used to enhance quality of life include:

• Invasive surgical method: This refers to the procedure of removing a specific portion of the colon, known as colectomy. It is generally an effective radical treatment.
• Stoma for defecation: When the terminal section of the colon is removed, this procedure is often preferred. Sometimes, to ensure the bowel functions as expected post-surgery, a section of the small intestine may be temporarily opened to the abdominal area for stool elimination. If it is close to the anus, the patient will defecate into a bag.
• In colon cancer, simply removing the tumor in the colon may not be sufficient. Some tissues and organs in areas where cancer has spread may need to be partially removed. This is because if only the cancerous tissues are removed, the remaining tissues may still harbor the disease, leading to a recurrence. Taking these precautions can prevent potential future complications.

What Precautions Can Be Taken to Prevent Colon (Bowel) Cancer?

To prevent colon cancer, it is essential to pay attention to dietary habits. Fiber-rich foods are healthy for the digestive system. A diet high in fiber content is beneficial. Excessively fatty or spicy foods can burden the intestines, so it is advisable not to consume these foods frequently. Adequate intake of calcium and vitamin D is crucial. Since being overweight can be a risk factor, individuals should engage in age-appropriate exercise. Patients at risk, particularly those aged 50 and above, should participate in regular screening tests for early diagnosis. If a person has a family history of colon cancer, they are expected to be more cautious. If possible, individuals should routinely monitor their bowel habits. If any symptoms are encountered, the individual should seek medical attention for evaluation.