Colorectal Cancer: Introduction, Prevalence, Causes, Screening, and Treatment

1. Introduction

Cancer is a general term for a group of diseases that are characterized by uncontrolled cell growth. Cancer can affect any tissue in the body and has the potential to spread to other parts of the body, a process known as metastasis. Colorectal cancer, also known as colon cancer or bowel cancer, is a type of cancer that begins in the large intestine (colon) or the rectum (end of the colon). Colorectal cancer is the third most common type of cancer in men and women in the United States. It is estimated that more than 140,000 people will be diagnosed with colorectal cancer in 2020 and more than 50,000 people will die from the disease. While colorectal cancer can occur at any age, the risk of developing the disease increases as you get older. The majority of colorectal cancers are diagnosed in people over the age of 50.

2. What is colorectal cancer?

Colorectal cancer is a type of cancer that begins in the large intestine (colon) or rectum (end of the colon). The colon and rectum are part of the digestive system, which removes waste from the body. The colon absorbs water and nutrients from food and produces stool, which is then stored in the rectum until it is ready to be eliminated from the body.

Most colorectal cancers start as noncancerous (benign) polyps on the inner lining of the colon or rectum. Over time, some of these polyps can become cancerous. When colorectal cancer starts in a polyp, it is referred to as adenocarcinoma.

There are two other less common types of colorectal cancers:
-carcinoid tumors: These tumors form in clusters of hormone-producing cells in the lining of the intestine.
-lymphomas: These tumors form in lymphocytes, a type of immune system cell.

3. Prevalence of colorectal cancer

The prevalence of colorectal cancer has been increasing over time. In 1975, the lifetime risk of developing colorectal cancer was about 6%. By 2002, this risk had increased to about 7%. The overall incidence rate for colorectal cancer has been stable over time, but there has been an increase in incidence rates among young adults (age 20-49 years). The rate of colorectal cancer deaths has been declining since its peak in 1989. However, African Americans have higher death rates from colorectal cancer than any other racial or ethnic group in the United States.

4. Causes of colorectal cancer

The exact cause of colorectal cancer is unknown, but there are several risk factors that have been identified. These include:
-Age: The risk of developing colorectal cancer increases with age. More than 90% of all cases are diagnosed in people over the age 50.
-Family history: People with a family history of colorectal cancer or Lynch syndrome (an inherited disorder that increases the risk of several types of cancers) are at increased risk for developing the disease themselves.
-Race: African Americans have the highest rates of colorectal cancer of any racial or ethnic group in the United States.
-Diet: A diet high in fat and low in fiber has been linked to an increased risk of colorectal cancer.
-Obesity: Being obese or overweight is a risk factor for developing colorectal cancer.
-Smoking: Smoking cigarettes is a risk factor for developing colorectal cancer.
-Alcohol: Drinking alcohol is a risk factor for developing colorectal cancer.
-Chronic inflammation: Conditions that cause chronic inflammation of the intestine, such as Crohn’s disease or ulcerative colitis, are risk factors for developing colorectal cancer.
-Certain types of polyps: Some types of polyps, such as adenomatous polyps, are more likely to become cancerous than others.
-Certain inherited syndromes: Inherited syndromes that increase the risk of colorectal cancer include familial adenomatous polyposis (FAP) and Lynch syndrome.

5. Screening for colorectal cancer

There are several screening tests that can be used to detect colorectal cancer. These tests can be divided into two main categories:
-Tests that look for abnormal cells in the colon or rectum: These tests include colonoscopy, sigmoidoscopy, and stool tests.
-Tests that look for signs of cancer in the blood: These tests include the CEA (carcinoembryonic antigen) test and the stool DNA test.

The most effective way to prevent colorectal cancer is to get screened for the disease. The American Cancer Society recommends that people at average risk for colorectal cancer begin screening at age 50. People at high risk for colorectal cancer may need to start screening earlier, and those at very high risk may need to be screened more often. There are several different ways to screen for colorectal cancer, and the best method for you will depend on your individual risk factors and preferences. Talk to your doctor about which screening test is right for you.

6. Risk assessment for colorectal cancer

There are several tools that can be used to assess your risk for developing colorectal cancer. The most common tool is the Fecal Occult Blood Test (FOBT), which looks for blood in the stool. Blood in the stool can be a sign of colon cancer or other digestive disorders. The FOBT is a simple test that can be done at home, and it is covered by most insurance plans. Other tools that may be used to assess your risk for colon cancer includeabdominal imaging tests (such as CT scans or MRI), genetic testing, and family history assessment. Your doctor can help you determine which tests are right for you based on your individual risk factors.

7. Treatment of colorectal cancer

The treatment of colorectal cancer depends on the stage of the disease. Stage I and II cancers can often be treated with surgery alone, while stage III and IV cancers may require additional treatments such as chemotherapy or radiation therapy. The 5-year survival rate for colorectal cancer is about 65%, but this varies depending on the stage of the disease.

8. Ethical considerations in research on colorectal cancer

Researchers who study colorectal cancer must consider the ethical implications of their work. This is because the disease affects a sensitive part of the body, and because the treatments for colorectal cancer can have serious side effects. Informed consent is a critical part of ethical research on colorectal cancer. This means that patients must be fully informed about the risks and benefits of participating in a study before they decide whether or not to participate. Informed consent forms must be written in language that is easy to understand, and patients must be given ample time to make their decision. If a patient decides to participate in a study, they should be able to change their mind at any time and withdraw from the study without penalty.

9. Conclusion

Colorectal cancer is a type of cancer that begins in the large intestine (colon) or rectum (end of the colon). The exact cause of colorectal cancer is unknown, but there are several risk factors that have been identified, including age, family history, diet, and obesity. Screening for colorectal cancer is the best way to prevent the disease. There are several different screening tests available, and the best method for you will depend on your individual risk factors and preferences. Talk to your doctor about which screening test is right for you.

FAQ

The symptoms of colorectal cancer can include bleeding from the rectum, a change in bowel habits, such as diarrhea or constipation, abdominal pain, and fatigue.

Colorectal cancer is diagnosed through a combination of tests, including a colonoscopy, CT scan, MRI, and blood tests.

The treatment options for colorectal cancer include surgery to remove the tumor, chemotherapy, radiation therapy, and targeted therapy.