Large Intestine Cancer, also known as Colorectal cancer (colon and rectum cancer), is an important health problem in the world and in our country. According to studies conducted in Western society, colorectal cancer is a disease that is frequently observed both in the United States and Europe and constitutes a significant portion of cancer-related deaths.
According to the Ministry of Health data, colorectal cancer ranks 4th in women and 4th in men. It is the 3rd most common type of cancer. Again, according to the list of inpatients in hospitals prepared by the Ministry of Health in 2003, colorectal cancer is the third most common after lung and breast cancer. Although these figures are quite frightening, two points about the disease should be known very well.
1- Colon cancer is a preventable disease.
2- Colon cancer has a full cure when caught at an early stage. It is a disease that can be treated.
WHAT IS CANCER?
All organs and tissues in our body work in order. Similarly, the cells that make up them grow, divide, multiply and die in a certain order. Loss of control mechanisms during the proliferation of normal cells in our body results in the formation of abnormal cells. Abnormal cell populations that proliferate out of control and spread to surrounding tissues and distant organs are generally called cancer.
Cancer Development in the Large Intestine
Large intestine cancer develops from the cells that form the layer covering the inner surface of the large intestine. Cancer cells constantly divide and multiply. For this reason, they do not have a specific program like normal cells. After performing their duties for a certain period of time, normal cells die in a programmed manner and are replaced by new cells from the same tissue. Cancer cells, on the contrary, multiply instead of dying, consume the nutritional resources that normal cells need, and may disrupt the functions of the organs they are in.
HOW DOES IT START?
Almost all colorectal cancers, There is a consensus that it starts from the base of a polyp. Polyp is the name given to a bulge and swelling that develops from the layer covering the inner surface of the intestine and grows into the intestine. Over time, cancer may occur on the basis of the polyp as a result of changes in the cells that form the polyp. Cancer cells, which are initially confined within the polyp, multiply over time and form a tumor mass, which invades the large intestine wall. Cancer cells that continue to grow uncontrollably may cause obstruction in the intestine after a certain period and spread to the surrounding and distant organs.
WHAT IS A POLYP?
Polyps are formations that develop as a result of the proliferation of cells that form the layer covering the inner surface of the large intestine and grow into the intestinal tract. Some polyps are flat, that is, sessile, and some are attached to the intestinal wall with a stalk.
Large Intestinal Polyp
Polyps are thick It is one of the most common diseases of the intestine. In a study conducted on healthy people, 15-20% polyps were detected in the large intestine of adult individuals. The probability of seeing polyps in the large intestine of an individual over the age of fifty increases and the rate reaches 40-50%. Polyps are observed mostly in the last parts of the large intestine, namely the sigmoid colon and rectum. This region is the region where large intestine cancer is most commonly seen.
COLLECTIVE CANCER AND GENETICS
The formation of large intestine cancer is related to genes. The relationship is quite complex. Simply put, genes are special units within chromosomes located in the nucleus of the cell, where all the characteristics of the living thing are carried. Each gene has different functions. They enable all our features to be determined and revealed, from the color of our hair to our finger shape and blood type. The formation and renewal of the layer covering the inner surface of the large intestine is also under the control of genes. Events occurring in the genetic structure initiate the development of changes in the layer covering the inner surface of the large intestine, which in normal health is renewed every 7-10 days. With the subsequent addition of additional genetic changes, early polyp, Then, late polyp and subsequent colon cancer development is observed. On average, the time it takes for cancer to develop from a polyp is about 8-10 years.
Cancer development from a polyp
Colorectal The importance of genes in cancer development
Multiple genetic events are needed for the development of colon cancer. These changes in the genetic structure do not happen suddenly.
We inherit some of them from our mother or father: When parents have children, they give them some of their own characteristics. For example, some cancer-causing damaged genes, such as hair and eye color, can also be passed on. These genes are necessary for the regular production of proteins, which are all the building blocks of our child. However, if the damaged genes inherited from the mother and father are passed on to the child, some normal protein production will not be possible. As a result, some diseases may occur. One of these is colon cancer.
Some of them occur during the development of the individual in the mother's womb and concern only that individual: Sometimes, there is no genetic disorder in the mother and father. However, damage may occur during the development of the offspring and disease may occur only in the child. In this way, even if hereditary colorectal cancer was not seen in previous members of the family, it can be inherited from now on and affect new family members.
Family Tree and Distribution of Large Intestine Cancer in Generations
Again, sometimes the disease is not seen even though the mother or father has a genetic disorder: Since these parents carry the genetic disorder with a recessive gene, the disease does not occur. These individuals are called carrier individuals. Even if the disease is not observed in carrier individuals, their children may have the disease. Because they can inherit the disease gene from both the mother and the father.
Some genetic disorders also develop with environmental factors during our lifetime: Some environmental agents can cause damage to the gene DNA. If the gene damage caused by these environmental agents causes cancer, then these environmental agents are called carcinogens (for example, smoking is a carcinogen). Due to these environmental factors, genes may be damaged or completely lost over time. As a result of this An important protein production and an important function in our body may be lost.
Colonal cancer occurs as a result of this genetic event, simply explained above, occurring during the renewal of the layer covering the inner surface of the large intestine.
As a result of research, it has been possible to detect some hereditary colorectal cancers with blood tests.
1.) Familial adenomatous polyposis (FAP): It is a hereditary colorectal cancer. Hundreds of polyp formations are seen in the large intestine. This disease is caused by the APC (adenomatous polyposis coli) gene located on chromosome 5. The disease occurs in 50% of children of an affected parent. The affected person can be detected with a blood test.
2.) Hereditary (hereditary) non-polyposis colorectal cancer (HNPCC): It forms another hereditary colorectal cancer. It occurs as a result of deterioration in two genes in chromosomes 2-3. The affected person can be detected with a blood test.
3.) Familial colon cancer: Although it is hereditary, no identifiable genetic disorder has yet been identified, such as the two hereditary types above. For this reason, it cannot be detected with a blood test.
4.) A genetic disorder that can help in the diagnosis of incidental colon cancer, which is the most common type of colon cancer, has not yet been identified. For this reason, it cannot be detected with a blood test.
Is there hereditary colorectal cancer in our family?
Those who have a family history of colon polyp or cancer in 3 or more relatives (especially if one of the patients was diagnosed with the disease under the age of 50), or in addition to one or more familial history of colon cancer or polyp. Those who have polyps or cancer may have hereditary or Familial Colon Cancer.
WHAT ARE THE SYMPTOMS AND SYMPTOMS?
Symptoms and findings vary depending on where the cancer is located in the large intestine. The most common symptom in cancers that develop on the right side of the large intestine (close to the area where it meets the small intestine) is hidden (unnoticed) blood loss along with the stool. Patients suffer from bleeding due to this bleeding that cannot be noticed visually. They come to the doctor complaining of hunger and fatigue. Complaints of extreme fatigue, inability to work as before, and shortness of breath may also be observed. Another important finding is a change in bowel habits. There may be occasional attacks of constipation and/or diarrhea. During this period, abdominal pain, bloating, and excessive gas may occur in addition to these findings.
In cancers located on the left side of the large intestine (close to the anus), complaints of stool mixed with blood are often observed. Patients complain of changes in defecation habits and frequent constipation. Inability to relax after defecation, abdominal pain (especially seen in the lower left side) and excessive gas and bloating are other symptoms.
These signs and symptoms can also be observed in other diseases. Therefore, a detailed examination is necessary for a definitive diagnosis. Abdominal pain and weight loss are often late findings indicating disseminated disease. Many polyps and cancers do not cause any signs or symptoms. For this reason, patients generally consult a doctor in the advanced stages of the disease.
General signs and symptoms seen in colon cancer;
- Blood from the anus discharge
- Blood in the stool
- Change in defecation habits
- Thinning of the stool
- Diarrhea and constipation attacks
- Anemia( anemia), weakness, constant fatigue
- Bloating, excessive gas
- Unexplained weight loss
IN WHICH REGION OF THE INTESTINE DOES IT DEVELOP MOST COMMON?
Large intestine cancer is most commonly seen in the last parts of the intestine, namely the sigmoid colon and rectum.
Formation Forms
1- Incidental Colon Cancer
Large Intestine Cancer A significant portion of them develop randomly, without being linked to any defined genetic disorder. This type of formation is observed in 65-85% of all colon cancers. No hereditary transmission is observed in incidental type colorectal cancer. Colon cancer can rarely be observed in more than one family member, but there is no strong familial history of colon cancer.
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