Colon cancer is a cancer of the large intestine (colon), the lower part of the digestive system. Cancer of the rectum is another cancer that is a few inches from the colon.
Most cases of colon cancer begin with small, non-cancerous (benign) clusters of cells called adenocarcinoma. Over time some of these polyps become colon cancer.
The polyps may be small. For this reason, doctors recommend regular screening tests to help prevent colon cancer by identifying and removing benign tumors before they become colon cancer.
Symptoms of colon cancer.
Signs and symptoms of colon cancer include:
Change in bowel function, including diarrhea or constipation or change in stool consistency, which lasts longer than four weeks
Bleeding from the rectum or blood appearing in the stool
Continued abdominal discomfort, such as cramps, gas or pain
Feeling that the intestine is not completely emptied
Weakness or fatigue
Uncertain weight loss
Many people with colon cancer do not show any symptoms in the early stages of the disease, and when symptoms appear, they are likely to vary depending on the size of the cancer and where it is located in the large intestine.
When you need to see a doctor.
If you notice any symptoms of colon cancer, such as blood in your stool or constant change in your bowel function, schedule an appointment with your doctor.
Talk to your doctor about when to start a colon cancer screening. The guidelines generally recommend that you start screening colon cancer at the age of 50. Your doctor may recommend more frequent or early screening if you have other risk factors, such as the family history of the disease.
Causes of colon cancer.
In most cases, it is not clear what causes colon cancer, and doctors know that colon cancer occurs when errors occur in the DNA of colon cells.
Healthy cells grow and divide in an organized way to keep your body functioning normally, but when the DNA of the cells becomes cancerous and cancerous, cells continue to divide – even when new cells are not needed, and when cells accumulate, they form a tumor.
Over time, cancer cells can grow to invade and destroy nearby natural tissues. Cancer cells can move to other parts of the body.
Genetic mutations increase the risk of colon cancer. Genetic mutations that increase the risk of colorectal cancer can be transmitted across generations. But these inherited genes are associated with only a small percentage of colon cancer and inherited genetic mutations do not make cancer unavoidable, but they can increase the risk of an individual becoming seriously ill.
The most common forms of inherited colon cancer syndromes are :
Hereditary nonpolyposis colorectal cancer.
Also called Lynch syndrome, it increases the risk of colon cancer and other cancers. People with this type of cancer tend to develop colon cancer before the age of 50 years.
Family glandular disease.
It is a rare disorder that causes the development of thousands of polyps in the lining of the colon and rectum, and people with this untreated type have a significant increase in the risk of colon cancer before the age of 40.
Congenital colon cancer syndrome can be detected by genetic testing. If you are concerned about your family’s history of colon cancer, talk with your doctor about whether your family history indicates that you have a risk of injury or not.
The relationship between diet and increased risk of colon cancer.
Studies conducted on large groups of people have shown that there is a correlation between diet and an increased risk of colon cancer. Especially the western model diet, high in fat and low in fiber.
When people move from areas where the typical diet is low in fat and high in fiber to areas where the typical western diet is more common, the risk of colorectal cancer in these people increases significantly.
It is not clear why this happens, but researchers are studying whether a high-fat diet, low fiber affects the microbes that live in the colon. Or causes underlying infections that may contribute to the risk of cancer. This is an area of active investigation, and research is underway.
Diagnosis of colon cancer.
Doctors recommend some screening tests for healthy people who have no signs or symptoms to look for early signs of colorectal cancer. Early colon cancer diagnosis offers the greatest chance of treatment and has been shown to reduce the risk of dying from colon cancer.
People with the risk of colon cancer may start screening at the age of 50, but people with increased risk, such as those with a family history, should be screened sooner, and African Americans and American Indians should examine the colon at the age of 45 years.
There are many diagnostic options and each has its own benefits and disadvantages. You should talk about diagnostic options with your doctor, and together you can decide which tests are right for you.
If your signs and symptoms indicate that you may have colon cancer, your doctor may recommend one or more tests, including:
Use a telescope to examine the inside of the colon. The colonoscopy uses a long, flexible, thin tube attached to a video camera and the entire colon and rectum monitor, and all suspicious areas. The doctor can pass surgical instruments through a tube to take tissue samples (biopsies) for analysis.
No blood test can tell us if you have this cancer. But your doctor may test your blood for evidence about your overall health.
Your doctor may also test your blood to make sure there is a chemical that sometimes produces this disease. Follow it may help your doctor understand the diagnosis and if the cancer responds to the treatment.
Stages of colon cancer.
If diagnosed with colon cancer, the doctor will order tests to determine the extent of the cancer. Staging helps determine which treatments are most appropriate for the condition.
Stage-setting tests may include imaging procedures such as a CT scan and in many cases, the cancer stage may not be determined even after colorectal cancer surgery.
Stages of cancer are:
The first stage.
Cancer growth through superficial lining (mucosa) of the colon or rectum. But, it did not spread outside the wall of the colon or rectum.
The second phase.
Cancer growth through the wall of the colon or rectum but has not spread to nearby lymph nodes.
Cancer may invade nearby lymph nodes but does not affect other parts of your body.
The fourth stage.
Cancer spread to distant sites, such as other organs – for example, to the liver or lung.