Overview

 

Colon cancer is a type of cancer that starts in the large intestine and spreads throughout the body (colon). The colon is the last section of the digestive system.

Colon cancer is more common in older people, but it can strike anyone at any age. It usually starts as polyps, which are small, noncancerous (benign) clumps of cells that form on the inside of the colon. Some of these polyps can turn into colon cancer over time.

Small polyps may produce few, if any, symptoms. As a result, doctors advise routine screening tests to help prevent colon cancer by detecting and removing polyps before they turn cancerous.

 

If colon cancer develops, a variety of treatments, including surgery, radiation therapy, and drug treatments such as chemotherapy, targeted therapy, and immunotherapy, are available to help control it. Colon cancer is also known as colorectal cancer, a term that combines colon cancer with rectal cancer, which starts in the rectum.

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Symptoms :

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The following are some of the signs and symptoms of colon cancer:

 

a) A change in your bowel habits, such as diarrhoea or constipation, or a change in the consistency of your stool, that persists.

b) Blood in your stool or rectal bleeding

c) Consistent abdominal aches and pains, such as cramps, gas, or pain

d) A feeling that your bowels aren't completely empty

e) Weakness or exhaustion

f) Weight loss that isn't explained

 

In the early stages of colon cancer, many people show no signs or symptoms. Symptoms will likely vary depending on the size and location of the cancer in your large intestine.

 

When should you see a doctor?

 

Make an appointment with your doctor if you notice any persistent symptoms that concern you. Consult your doctor about when you should start colon cancer screening. Colon cancer screenings should begin around the age of 50, according to most guidelines. If you have other risk factors, such as a family history of the disease, your doctor may recommend more frequent or earlier screening.

 

Causes:

Most colon cancers are caused by unknown factors, according to doctors. In general, colon cancer develops when the DNA of healthy colon cells undergoes mutations. The DNA of a cell contains instructions that tell it what to do.

 

Healthy cells divide and grow in a regular pattern to keep your body running smoothly. When a cell's DNA is damaged and it becomes cancerous, however, the cell continues to divide despite the fact that new cells aren't required. As the cells multiply, a  tumour develops. Cancer cells can grow large enough to invade and destroy normal tissue nearby over time. Furthermore, cancerous cells have the ability to travel to other parts of the body and form deposits there (metastasis).

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Risk Factors:

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1. Age : Colon cancer can strike anyone at any age, but the majority of those diagnosed are over 50. Colon cancer rates in people under the age of 50 have been rising, but doctors aren't sure why.

 

2. African-American ethnicity: Colon cancer is more common in African-Americans than in people of other races.

 

3. Having had colorectal cancer or polyps in the past: You have a higher risk of colon cancer in the future if you've already had colon cancer or noncancerous colon polyps.

 

4. Inflammatory bowel disease (IBD) : Colon inflammatory diseases like ulcerative colitis and Crohn's disease can raise your chances of getting colon cancer.

 

5. Inherited syndromes that increase the risk of colon cancer : Some gene mutations passed down through generations can significantly increase your risk of colon cancer. Inherited genes are linked to only a small percentage of colon cancers. Familial adenomatous polyposis (FAP) and Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, are the two most common inherited syndromes that increase colon cancer risk (HNPCC).

 

6. Colon cancer runs in the family : If you have a blood relative who has had colon cancer, you're more likely to get it. If you have a family history of colon or rectal cancer, your chances are even higher.

 

7. A high-fat, low-fiber diet: A typical Western diet, which is low in fibre and high in fat and calories, may be linked to colon and rectal cancer. The results of research in this area have been mixed. People who eat a diet high in red meat and processed meat have an increased risk of colon cancer, according to some studies.

 

8. A sedentary way of life:  Inactive people are more likely to develop colon cancer. Colon cancer risk may be reduced by engaging in regular physical activity.

 

9. Diabetes. Colon cancer is more likely in people who have diabetes or insulin resistance.

 

10. Obesity. When compared to people of normal weight, obese people have a higher risk of colon cancer and a higher risk of dying from colon cancer.

 

11. Smoking. Smokers may be at an increased risk of colon cancer.

 

12. Alcohol. Colon cancer is more likely if you drink a lot of alcohol.

 

13. Radiation therapy used to treat previous cancers in the abdomen raises the risk of colon cancer.

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Prevention:

Colon cancer screening:

Colon cancer screening is recommended for people with an average risk of colon cancer around the age of 50, according to doctors. People with a higher risk of colon cancer, such as those who have a family history of the disease, should consider screening sooner. There are several screening options available, each with its own set of advantages and disadvantages. Talk to your doctor about your options, and the two of you can decide which tests are right for you.

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A) Changes in your lifestyle to lower your risk of colon cancer- By making small changes in your daily routine, you can lower your risk of colon cancer. Take the following steps:

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• Consume a diverse selection of fruits, vegetables, and whole grains. Vitamins, minerals, fibre, and antioxidants found in fruits, vegetables, and whole grains may help to prevent cancer. To get a wide range of vitamins and nutrients, eat a variety of fruits and vegetables.

• If you must drink alcohol, do so in moderation. If you choose to drink alcohol, limit yourself to one drink per day for women and two drinks per day for men.

• Quit smoking. Consult your doctor about quitting methods that might work for you.

•  Exercise. On most days of the week , try to get at least 30 minutes of exercise. Start slowly and gradually increase to 30 minutes if you have been inactive. Also, before beginning any exercise programme, consult your doctor.

 

Maintain a healthy body mass index (BMI). If you're at a healthy weight, keep it off by combining a nutritious diet with daily exercise. If you need to lose weight, talk to your doctor about how to do so in a healthy way. Aim to lose weight gradually by increasing your physical activity and lowering your calorie intake.

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B) Colon cancer prevention for high-risk individuals

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Some drugs have been discovered to lower the risk of precancerous polyps or colon cancer. Regular use of aspirin or aspirin-like drugs, for example, has been linked to a lower risk of polyps and colon cancer. However, it is unclear what dose and duration of treatment would be required to reduce the risk of colon cancer. Aspirin use on a daily basis carries some risks, such as gastrointestinal bleeding and ulcers.

 

These options are usually only available to people who are at a high risk of colon cancer. There is insufficient evidence to recommend these drugs to people who have an average risk of colon cancer.

 

If you have a higher risk of colon cancer, talk to your doctor about your risk factors to see if you should take any preventative medications.

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Diagnosis:

Cancer screening:

In order to look for signs of colon cancer or noncancerous colon polyps, doctors recommend certain screening tests for healthy people who have no signs or symptoms. The best chance for a cure is to detect colon cancer at its earliest stage. Colon cancer screening has been shown to reduce the risk of death from the disease.

 

People with an average risk of colon cancer should start screening around the age of 50, according to doctors. People with a higher risk of colon cancer, such as those with a family history of the disease or those of African-American ancestry, should consider screening sooner.

 

There are several screening options available, each with its own set of advantages and disadvantages. Talk to your doctor about your options, and the two of you can decide which tests are right for you. If a colonoscopy is used for screening, polyps can be removed before they turn into cancer during the procedure.

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Cancer diagnosis:

 If your signs and symptoms suggest you may have colon cancer, your doctor may suggest one or more tests and procedures, such as:

 

• Examining the inside of your colon with a scope (colonoscopy). Colonoscopy is a procedure that involves viewing your entire colon and rectum through a long, flexible, and slender tube connected to a video camera and monitor. If any suspicious areas are discovered, your doctor can use surgical tools to remove polyps and take tissue samples (biopsies) for analysis.

• Tests on the blood. There is no way to tell if you have colon cancer from a blood test. Your doctor, on the other hand, may perform blood tests to determine your overall health, such as kidney and liver function tests. Your doctor may also perform a blood test to look for a chemical produced by colon cancers (carcinoembryonic antigen, or CEA). The level of CEA in your blood, when measured over time, can help your doctor determine your prognosis and whether your cancer is responding to treatment.

• Determining the cancer's extent: Your doctor may recommend tests to determine the extent (stage) of your colon cancer if you've been diagnosed with it. Staging aids in determining which treatments are best for you.

• Imaging procedures such as abdominal, pelvic, and chest CT scans or PET scan may be used as part of the staging process. The stage of your cancer may not be fully determined until after your colon cancer surgery in many cases.

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Stages of Cancer:

Colon cancer stages are denoted by Roman numerals ranging from 0 to IV, with the lowest stages indicating cancer that is limited to the lining of the colon. The cancer has spread (metastasized) to other parts of the body by the time it reaches stage IV.

 

Treatment:

The type of treatment you receive for colorectal cancer may be determined by the disease's "stage." Except for stage IV, you will have surgery to remove the tumour first. Other treatments may be available.

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A) Treatment for Colorectal Cancer in Stage 0:

Colorectal cancer in stage 0 affects only the innermost lining of the colon or rectum. It should be possible to remove it with surgery. Your treatment will be determined by the size of the cancer. Your surgeon may be able to remove the tumour as well as some surrounding tissue. This procedure is known as a polypectomy. If your tumours are larger, your surgeon may need to remove the diseased part of the colon and reattach the healthy tissue to keep your bowels working. This is referred to as an anastomosis. Radiation therapy, either externally (beamed in from the outside) or internally (beamed in from the inside), may be considered by your doctor (radioactive beads that go inside your body).

 

B) Treatment for Colorectal Cancer in Stage I:

Stage I tumors have spread to the second and third layers of the colon or rectum, as well as the inside wall. The cancer hasn't spread to the bowel's outer wall or beyond it.

 

Most people will have surgery at this point to remove the cancer and a small amount of surrounding tissue. Additional treatments are unlikely to be required.

 

Your doctor may only use radiation if the tumor is small or you are very old or sick. They may also include chemotherapy to help with the treatment.

 

C) Treatment for Colorectal Cancer in Stage II:

Colorectal cancers in stage II are larger and penetrate the bowel's muscular wall. They could have spread to other parts of the body, such as the bladder, uterus, or prostate gland. However, cancer does not exist in distant organs or lymph nodes, which are small structures that produce and store cells that fight infection and filter out harmful substances.

 

You'll almost certainly need surgery to remove the cancer and any surrounding areas, as well as any areas where it has spread. Before or after surgery, you may receive radiation and chemotherapy.

 

D) Treatment for Colorectal Cancer in Stage III:

Colorectal cancers in stage III have spread to one or more lymph nodes. Your doctor may discuss tumours in stages lIl A, B, or C with you. This is what it means: 

lIlA : Tumors affect the lymph nodes and are found in the colon or rectum wall.

 

lIlB : Tumors have spread to one to four lymph nodes after breaking through the wall.

 

lIlC : Tumors have spread to more than four lymph nodes at this stage.

 

Treatment entails:

If possible, surgery to remove the tumor and all involved lymph nodes. Chemotherapy following surgery, if the tumor is large and has spread to nearby tissue, it may be treated with radiation.

 

E) Treatment for Colorectal Cancer in Stage IV:

Colorectal cancers in stage IV have spread to other parts of the body, most commonly the liver or lungs. Your doctor may refer to the cancer as having "metastasized" or "metastatic" cancer.

 

The tumor may or may not include your lymph nodes, and it can be of any size.

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The following treatments may be used:

 

1) Chemotherapy. At this point, this is the primary treatment. You may also receive medications such as:

 

2) Bevacizumab (Avastin), cetuximab (Erbitux), or panitumumab are some of the anti-cancer drugs available (Vectibix). These medications affect your immune system. Monoclonal antibodies are what your doctor may refer to them as.

 

If your cancer has progressed or hasn't responded to other treatments, you may be prescribed Ziv-Aflibercept (Zaltrap).

 

3) Therapy that is specific to the patient. If your colorectal cancer has spread despite other treatments, your doctor may recommend regorafenib (Stivarga).

 

4) Surgery. You may need surgery to remove the cancer from your colon and other areas where it has spread. Alternatively, you could have surgery to bypass the cancer and reconnect the parts of your colon that are healthy. Surgery can often relieve or prevent rectum blockage, as well as treat difficult-to-control bleeding. Although it isn't considered a cure, it may help you live longer. Your surgeon may be able to remove one or both of your liver tumours. Other options include freezing the tumours (cryosurgery) or using microwaves or heat to destroy them (radiofrequency ablation).

 

5) Radiation therapy: Radiation therapy kills cancer cells by using high-energy sources like X-rays and protons. It could be used to shrink a large cancer before an operation, making it easier to remove. Radiation therapy may be used to relieve symptoms such as pain when surgery is not an option. Chemotherapy and radiation are sometimes used together.

 

6) Drug therapy with a specific goal:

Targeted drug treatments are designed to target specific abnormalities found in cancer cells. Targeted drug treatments can kill cancer cells by blocking these abnormalities.

 

7) Chemotherapy is frequently used in conjunction with targeted drugs. People with advanced colon cancer are usually treated with targeted drugs.

 

8) Immunotherapy: Immunotherapy is a cancer-fighting drug that activates your immune system. Because cancer cells produce proteins that prevent immune system cells from recognising cancer cells, your body's disease-fighting immune system may fail to attack your cancer. Immunotherapy works by interfering with the immune system's natural processes.

 

Immunotherapy is typically used only in the case of advanced colon cancer. Your cancer cells may be tested by your doctor to see if they're likely to respond to this treatment.

 

9) Palliative (supportive) care: Palliative care is a type of medical treatment that focuses on relieving pain and other symptoms associated with a serious illness. Palliative care is provided by a team of doctors, nurses, and other specially trained professionals who collaborate with you, your family, and your other doctors to add an extra layer of support to your ongoing care.

 

Palliative care teams are dedicated to enhancing the quality of life for cancer patients and their families. This type of treatment is provided in addition to any curative or other treatments you may be receiving. People with cancer may feel better and live longer when palliative care is used in conjunction with all other appropriate treatments.

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If Colorectal Cancer Recurs, What Should You Do?

 

If colorectal cancer returns (recurs) after treatment, doctors refer to it as “recurrent.” It can happen in the same spot or somewhere else on your body. People who had more advanced colorectal cancer the first time are more likely to have a recurrence. The following treatments may be used:

 

1) Surgical removal of the cancer. According to studies, this can help people live longer.

 

2) If all of the cancer cannot be removed during surgery, chemotherapy with or without radiation is used. This can sometimes cause the tumor to shrink to the point where surgeons can remove it later.

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