Colorectal Cancer

What are Colorectal Cancers?

In the upper part of the large intestine, which is one of the organs of the digestive system, approximately 150-180 cm is the colon, 15-17 cm in the lower part is the region called the rectum and below it is the anal canal. Cancer seen in the colon and rectum is called colorectal cancer. Polyps in the colon and rectum constitute 90% of colorectal cancers. Recognizing at an early stage and removing these polyps, which are likely to turn into cancer in about 5-10 years, significantly reduces the risk of colorectal cancer.

Prevelance of Colorectal Cancers

Colorectal cancer is the third most common cancer among all cancers. While colorectal cancers, which are more common in men worldwide, are in the third place after lung and prostate cancer in men, it comes after breast cancer in terms of prevelance in women. Early diagnosis of colorectal cancer, which is a lethal type of cancer, and the use of new treatment methods with the development of technology are among the factors that reduce the death rate.

Causes and Risk Factors of Colorectal Cancers

Among the causes of colorectal cancer are changeable factors such as unhealthy nutrition, as well as unchangeable gender, aging and genetic factors. In general terms, the causes and risk factors of colorectal cancer can be listed as follows:


Colorectal cancer is a type of cancer that can occur at any age. However, studies show that 90% of patients diagnosed with colorectal cancer are in the group over the age of 40.


Polyps, whose prevelance is higher in people aged 50 and over, may be benign, but in some cases they may turn into cancer over time. For this reason, polyp formation should be detected early with regular screenings and these polyps should be removed from the body before they turn into cancer.

Family history of colorectal cancer

It can be said that if there is a history of colorectal cancer in first degree relatives such as mother, father and sibling, the probability of developing colorectal cancer in that person will increase. People with a family history of colorectal cancer should start screening tests 10 years before the age at which a family member is diagnosed with the disease.

Genetic Disorders

Hereditary cancer syndromes such as familial adenomatous polyps are among the factors that increase the risk of colorectal cancer. People with these and similar disorders should have genetic testing and be followed up with colonoscopy from a young age.

Previous Colorectal Cancers

It should also be kept in mind that patients who have had colorectal cancer before are more likely to develop this disease again. At the same time, breast, uterine and ovarian cancers increase the incidence of colorectal cancer approximately 2 times.

Ulcerative Colitis or Crohn's Disease

Inflammatory intestinal diseases (ulcerative colitis and Crohn's disease) are triggers for colorectal cancer. People with these diseases are 10 times more likely to develop colorectal cancer than other people.

Unhealthy Lifestyle

Excessive consumption of red meat and processed meat, animal fats and carbohydrate-rich foods, not including enough fiber in the nutrition, and low consumption of fruits and vegetables are among the factors that increase the risk of colorectal cancer. Inactive (sedentary) life, smoking and alcohol use and obesity are also factors that increase the risk of cancer. Vitamins A, C, and E may help reduce the development of cancer. At the same time, patients with type 2 diabetes are also more likely to develop colorectal cancer than other people.

Symptoms of Colorectal Cancers

In colorectal cancers, as in all types of cancer, there are some common symptoms that help to diagnose. These symptoms can be minor ailments such as hemorrhoids. However, it should be kept in mind that in most cases, colorectal cancer does not show any symptoms or severe pain-like symptoms occur in advanced stages. In case the tumor grows in the large intestine, serious disorders such as intestinal obstruction and related intestinal entanglement can also be seen. The most common symptoms of colorectal cancer are as follows:
• Blood in the stool
• Diarrhea or constipation, sudden and unexpected changes in intestinal movements
• unexplained weight loss
• Stomachache
• feeling tired
• Weakness
• Anemia due to iron deficiency
• thinning in the stool
• Vomiting
• Frequent gas pains, cramps
• Feeling of fullness in the abdomen
These symptoms alone are not sufficient for a diagnosis of colorectal cancer. However, it is of great importance for early diagnosis for people who still have one or more of the symptoms to consult a doctor without delay.

Stages of Colorectal Cancers

Colorectal cancer, like other cancers, progresses gradually. After the diagnosis of cancer is made, it is determined to what stage the cancer has progressed and a treatment plan is drawn up accordingly.
•Stage 1: The cancer has spread to the intestinal wall. However, cancerous cells have not yet reached the outside of the colon.
•Stage 2: Cancer has spread to all intestinal folds. There is no spread to lymph nodes.
•Stage 3: Cancer has spread only to nearby lymph nodes and has not metastasized to other organs or lymph nodes.
•Stage 4: Cancer has spread to distant organs and tissues such as the lung and liver.

Diagnosis of Colorectal Cancers

Colorectal cancers, like many cancers, progress without showing many symptoms until the tumor grows. For this reason, polyps should be diagnosed by making regular checks and these polyps should be removed with early intervention.  In addition to routine check-ups, there are some tests that should be done to diagnose cancer in people who show symptoms. As a result of the tests, cancer can be diagnosed and the stage of the cancer can be determined.

Physical Examination

First of all, family history, changes in intestinal movements and defecation, weight loss and bleeding of people who apply to the doctor with certain complaints are questioned. Other diseases of the patient are also examined, and then a rectal touch examination is performed. Rectal touch, on the other hand can be defined as an anus examination performed by the doctor through the finger.

Complete Blood Count

Complete blood count is an important test for diagnosis. In addition, the change in the level of red blood cells of people with bleeding can be determined by this test. This is a sign of anemia.

Examination of occult blood in stool

This test, which determines whether there is occult blood in the stool sample that the patient will give, is also among the tests that help diagnose.


The last 60-70 cm of the large intestine, including the anus, rectum and sigmoid colon, is examined by an instrument with a camera at the end. During this procedure, called rectosigmoidoscopy, polyps and abnormal areas are examined.


In the colonoscopy method, the inner surface of the large intestine is examined through a device from the anus. The difference of this procedure from rectosigmoidoscopy is that the entire large intestine can be examined in colonoscopy. Tissue samples can be taken for biopsy during colonoscopy, or polyps can be taken from the body. In addition, cancer cases that are diagnosed early and have not progressed can be treated with colonoscopy.

Other Imaging Methods

With imaging tests such as MR (magnetic resonance), US (ultrasound), CT (computed tomography) and PET (positron emission tomography), it is possible to detect how far the cancer has spread, other suspicious areas where the cancer may metastasize, and whether the treatment is effective.

Treatment of Colorectal (Large Intestine) Cancers

It can be said that the primary treatment method in colorectal cancers is surgical methods. Chemotherapy and radiotherapy are other treatment methods used depending on the stage of the cancer. Before starting the treatment, the stage of the cancer should be determined and the patient should be informed about the treatment options, the side effects of these treatment options and the changes that can be seen after the surgery.

It should be not forgotten that the treatment of colon and rectal cancer is done differently. Therefore, whether surgery or chemotherapy/radiotherapy is preferred in these two types of cancer may vary from patient to patient.

In the surgical method used in the treatment of colon cancer, the cancerous area and part of the intestine on both sides of the tumor are removed. After the tumorous area is removed, both ends of the intestine are tied together. However, in some cases, after removing the diseased part of the colon, the remaining part may need to be attached to the anterior abdominal wall. As a result of this intervention, called a colostomy, stool comes out of the bags placed on the abdominal wall, not from the anus. This may be temporary, or in some cases it may be permanent. Chemotherapy applied to colon cancer patients can be carried out together with surgical methods in cases of second-stage cancer. In the third stage, chemotherapy is applied after the surgery, while in the fourth stage it is not possible to resort to surgical methods and in this case only chemotherapy is applied. In some patients, it may not be possible to apply surgical methods after chemotherapy.
In rectal cancer, on the other hand, surgical methods can be applied in cases where cancerous cells are seen only in the last part of the large intestine. In this case, part of the rectum can be removed or the whole can be removed. Temporary colostomy is also a method applied after rectal cancer surgery. However, if the tumor is close to the anus, the muscle controlling defecation is also removed with the tumor, and it should be not forgotten that the colostomy procedure is permanent in this case. Chemotherapy and radiotherapy are applied together with surgical intervention in second and third stage cancer cases. Therapies can be administered before, during and after surgery. In the fourth stage rectal cancer, chemotherapy is applied primarily. In some patients, radiotherapy and surgery may be used in addition to chemotherapy.

Thanks to the experience accumulated for many years in the treatment of colon and rectal cancers, laparoscopic surgeries performed with the help of camera systems and elongated hand tools through small holes drilled in the abdominal wall, and Davinci robotic surgery, which is a more advanced method, has reached today's point. At this point, we perform surgeries that are less painful and offer better cosmetic results to our patients.
With the help of advanced high-definition HD camera systems, less bleeding, urination and better protection of the nerves for performing sexual sensory functions are provided thanks to the surgical anatomy, which is seen in much more detail compared to open surgery.

In addition, in the last 10 years, the early stages of rectal cancer can be successfully treated and the anus can be protected, with long non-surgical chemotherapy and radiotherapy applications called NOM.  In addition to this progress, especially in rectal cancer, with individualized treatments and targeted therapies, treatment tailoring can be done and specific treatments can be planned for the person and the disease. If the treatment of colorectal cancers is carried out in an integrative approach in centers where tumor boards work well, radiation oncology, surgery, gastroenterology, medical oncology, nuclear medicine, pathology, radiology/interventional radiology and stomotherapy units are gathered and the use of contemporary guidelines is mandatory, the most successful stage-specific good survival rates will be achieved.

Created at 11.10.2023 06:20
Updated at 29.10.2023 06:57
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