Colon cancer — symptoms, diagnosis, treatment

Colorectal cancer is one of the most commonly diagnosed cancers in the entire world population. According to the statistics of the Global Cancer Observatory (part of the World Health Organization), in 2030 the incidence of this type of cancer will increase to 1.51 million cases worldwide.

What is the colon responsible for?

The large intestine is part of the digestive system where the final stage of absorbing water, electrolytes and minerals takes place, which results in stool formation. Additionally symbiotic bacteria living in the colonic lumen produce vitamin K (playing a vital role in blood clotting) and some B vitamins.

Unlike the small intestine, the large intestine is not lined with intestinal villi. The mucosa of the large intestine is strongly folded, which increases its surface area. The structure of the large intestine consists of the following parts:

• Cecum (caecum), from which the appendix comes out;
• Colon, which is divided into:
  • Ascending (left) colon;
  • Transverse colon;
  • Descending (right) colon;
  • Sigmoid colon.
• Rectum.

What are the symptoms of colon cancer?

Symptoms accompanying colorectal cancer depend on its location and stage. Moreover, the disease may not manifest itself for many years. When symptoms characteristic of colorectal cancer appear, the disease is usually at an advanced stage.

The most common symptoms include:

• Bleeding from the gastrointestinal tract — presence of blood in the stool occurs in approximately 80% of patients with rectal cancer, 45% of patients with cancer of the left half of the colon and 20% of patients with cancer of the right half of the colon; presence of blood in the stool appears with tumors located further in the intestines; and occult blood is detected in 80% of colorectal cancer patients;
• Anemia — occurs as a consequence of bleeding that results in iron deficiency; it is accompanied by fatigue, weakness, shortness of breath, increased heart rate, decreased hemoglobin level;
• Change in bowel habits and stool consistency — your stools may become tarry when bleeding occurs; the bowel cycle is also disturbed, which is manifested by alternating diarrhea and constipation.

Moreover, the development of cancer may be accompanied by pain and discomfort in the abdomen and the feeling of incomplete bowel movement. You should see a doctor as soon as possible after noticing symptoms characteristic of colorectal cancer.

Colon cancer — causes

The main factors that increase your risk of developing colorectal cancer are lifestyle related:

• Diet — lack of a balanced diet, low in vegetables and fruits, eating a lot of red meat, especially after heat treatment (fried, grilled), a large amount of saturated fat.
• Being overweight, obesity;
• Low or no physical activity;
• Smoking;
• Excessive alcohol consumption;
• Diabetes.

Moreover, increased morbidity may be due to genetic factors. Colorectal cancer can occur in people with a family history of this disease. People with adenomatous polyposis, Lynch syndrome, Peutz-Jeghers syndrome, MYH mutation polyposis, and acromegaly are also at risk. The risk of developing colorectal cancer is also higher if you have inflammatory bowel disease.

Colorectal cancer — diagnosis

The main test used in the diagnosis of colorectal cancer is colonoscopy. It allows not only a detailed examination of the tumor, but also obtaining tissue samples. Such a sample is sent to a laboratory for histopathological analysis, the result of which gives information about the degree of malignancy of the tumor. In order to determine the stage of the disease, imaging diagnostics are performed — e.g., computed tomography. Blood tumor markers are also tested.

Colorectal cancer-— treatment

The choice of the appropriate treatment method is determined by the results of diagnostic tests. Thanks to them, it is possible to determine the location of the tumor, the degree of advancement and the general condition of the patient. Surgery, chemotherapy, and radiation therapy are among the most frequently chosen treatments. When the cancer is in its early stages, the operations performed are usually minimally invasive. On the other hand, in the case of more advanced stages, it may be necessary to perform a partial or total colectomy, i.e., a procedure to remove the large intestine. This procedure is associated with the risk of not being able to connect the remaining sections. In such cases, a stoma is included in the treatment, which allows the contents of the intestines to be emptied into a special bag. After the procedure, chemotherapy is often used. Its aim is to stop the development of cancer and minimize the risk of relapse.

Diet for colorectal cancer

A key factor in treatment is following a healthy and well-balanced diet, that meets nutritional requirements of the patient. The symptoms associated with the disease can cause loss of appetite and anorexia, which can lead to weight loss and weakness of the body. A diet of a person suffering from colorectal cancer should provide them with all the nutrients, while being easily digestible. A very important element of the diet of cancer patients is to provide the right amount of calories and protein. Thanks to this, it is possible, it is possible to maintain the immune system in good condition. Before implementing modifications to the diet, it is worth seeking advice from a dietitian, who will create a nutrition plan tailored to the needs of a given patient.

Colon cancer — prognosis

The prognosis for colorectal cancer is closely related to the stage of the disease. According to the American Cancer Society, the 5-year survival rate for the primary tumor is 91%, for lymph node metastases 72%, and for distant metastases 14%.

Colon cancer — prevention

The prevention of colorectal cancer mainly involves changing the habits to healthy ones. Most often, this requires introducing changes in the diet and incorporating activity into the daily routine. It is recommended to limit alcohol consumption and to quit smoking. In addition, regular tests (like a colonoscopy) should be performed to detect possible neoplastic changes at an early stage.