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.

Prevalence of Colorectal Cancers

Colorectal cancer ranks as the third most prevalent cancer across all types. While colorectal cancers, which are more common in men worldwide, are in third place after lung and prostate cancer in men, it comes after breast cancer in terms of prevalence 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:

Age

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

Polyps, whose prevalence 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 become cancerous.

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 ten 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 two 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 ten 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 cancer development. At the same time, patients with type 2 diabetes are also more likely to develop colorectal cancer than other people.

Symptoms of Colorectal Cancers

If a tumor grows in the colon, severe disorders such as bowel obstruction and associated bowel entanglement can be observed. The most common symptoms of colorectal cancer are as follows:
• Blood in the stool
• Diarrhea or constipation, sudden and unexpected changes in bowel movements
• Unexplained weight loss
• Stomachache
• Feeling tired
• Weakness
• Iron deficiency anemia
• Thinning of 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, for an early diagnosis, it is essential that people who still have one or more symptoms consult a doctor without delay.

Stages of Colorectal Cancer

Colon cancer, like other cancers, progresses gradually. After a cancer diagnosis is made, the stage of the cancer is determined, and a treatment plan is made accordingly.
•Stage 1: The cancer has spread to the intestinal wall. However, cancer cells have not yet reached the outer side of the colon.
•Stage 2: The cancer has spread to all layers of the intestine. There is no spread to the lymph nodes.
•Stage 3: The cancer has spread only to nearby lymph nodes and has not metastasized to other organs or lymph nodes.
•Stage 4: The cancer has spread to distant organs and tissues such as the lungs and liver.

Diagnosis of Colorectal Cancer

Colorectal cancers, like many cancers, progress without showing many symptoms until the tumor grows. For this reason, polyps should be diagnosed with regular checks, which should be removed by early intervention. In addition to routine examinations, some tests should be done to diagnose cancer in people who show symptoms. Tests can diagnose cancer and determine its stage.

Physical Examination

First, the family history, changes in bowel movements and defecation, weight loss, and bleeding of people who report to the doctor with certain complaints are questioned. Other diseases of the patients are also examined, and 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

A complete blood count is an essential diagnostic test. It can also determine whether the level of red blood cells has changed in people with bleeding, which is a sign of anemia.

Fecal Occult Blood Test

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

Rectosigmoidoscopy

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

Colonoscopy

In the colonoscopy method, the inner surface of the colon is examined using a device from the anus. This procedure differs from rectosigmoidoscopy because the entire colon can be viewed in colonoscopy. Tissue samples can be taken for biopsy during colonoscopy, or polyps can be removed from the body. In addition, cases of cancer that are diagnosed early and have not progressed can be treated with colonoscopy.

Other Imaging Methods

With imaging tests such as MRI (magnetic resonance imaging), 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 cancer may metastasize, and whether the treatment is effective.

Treatment of Colorectal (Large Intestine) Cancer

The primary treatment for colorectal cancer is surgery. Chemotherapy and radiotherapy are other options depending on the stage of the tumor. Before starting 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 may be seen after surgery.

It should be noted 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 to treat colon cancer, the cancerous area and part of the intestine on both sides of the tumor are removed. After removing the tumor area, both ends of the intestine are tied together. However, in some cases, the remaining part may need to be attached to the anterior abdominal wall after removing the diseased part of the colon. As a result of this intervention, called colostomy, the stool exits through bags placed on the abdominal wall instead of the anus.

This may be temporary or, in some cases, permanent. Chemotherapy applied to patients with colon cancer can be performed together with surgical methods in cases of second-stage cancer. Chemotherapy is applied after surgery in the third stage. In contrast, in the fourth stage, it is impossible to resort to surgical methods; in this case, only chemotherapy is used. 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 cancer cells are seen only in the last part of the colon. In this case, part of the rectum can be removed, or the entire rectum can be removed.

A temporary colostomy is also a method applied after rectal cancer surgery. However, suppose the tumor is close to the anus. In that case, the defecation muscles are also removed with cancer, and it should not be forgotten that the colostomy procedure is permanent in this case. Chemotherapy and radiotherapy are applied together with surgical intervention in cases of second and third stage cancer.

Treatments can be applied before, during, and after surgery. In the fourth stage of rectal cancer, chemotherapy is primarily applied. In addition to chemotherapy, radiotherapy and surgery can be used in some patients.

Thanks to the experience accumulated over many years in the treatment of colon and rectal cancer, 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, have reached the present point.

At this point, we perform less painful surgeries and offer better cosmetic results to our patients. With the help of advanced HD high-definition camera systems, less bleeding, urination, and better nerve protection for performing sexual sensory functions are ensured thanks to surgical anatomy, which is seen much more clearly compared to open surgery.

In addition, in the last ten years, 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, in individualized treatments and targeted therapies, treatment can be tailored, and specific treatments for the person and the disease can be planned.

If colorectal cancers are treated with an integrative approach in centers where tumor boards function well, including radiation oncology, surgery, gastroenterology, medical oncology, nuclear medicine, pathology, radiology/interventional radiology, and tomotherapy units, and the use of modern guidelines is mandatory, the most successful reasonable survival rates specific to the stage will be achieved.