Colon Cancer – Overview
A type of cancer that begins in the large intestine i.e. colon is known as colon cancer. The final part of the digestive tract is the colon.
Older adults are generally affected with colon cancer typically, though it can happen at any age. It usually starts as small, noncancerous (benign) clumps of cells known as polyps that form on the inside of the colon. Over the period of time, some of these polyps can become colon cancers.
Polyps may be small and develop few, if any, symptoms. For this reason, regular screening tests are suggested by the doctors to help prevent colon cancer by identifying and removing polyps before they turn into cancer.
If colon cancer is produced, for controlling it many treatments are available including surgery, radiation therapy and drug treatments, such as chemotherapy, targeted therapy and immunotherapy.
Colon cancer is sometimes known as colorectal cancer, which is a term that is a mixture of colon cancer, and rectal cancer, and which starts in the rectum.
Colon Cancer – Symptoms
Signs and symptoms of colon cancer may include:
- A continuous change in the bowel habits which may include diarrhea or constipation or a change in the consistency of stool
- Rectal bleeding or blood in the stool
- Continuous abdominal discomfort, such as cramps, gas or pain
- A feeling that the bowel doesn’t empty fully
- Weakness or fatigue
- Unexplained weight loss
No symptoms are experienced with many people having colon cancer in the early stages of the disease. Symptoms are likely to differ when they appear, depending on the cancer’s size and location in the large intestine.
If any persistent symptoms are noticed that are worrisome, make an appointment with the doctor should be made.
The doctor should be contacted about when to begin colon cancer screening. Generally recommended guidelines are that colon cancer screenings begin around 50. More frequent or earlier screening might be suggested by the doctor if having other risk factors, such as a family history of the disease.
Colon Cancer – Causes
What causes most colon cancers is not certain by the doctor
In general, colon cancer begins when changes are developed in healthy cells in the colon (mutations) in the DNA. A set of instructions that tell a cell what to do is contained in DNA of a cell
To keep the body to function normally the healthy cells grow and divide in an orderly way. But when a cell’s DNA is damaged and becomes cancerous, division of cells continue even when new cells aren’t needed. A tumor is formed as the cells accumulate.
With the period of time, the cancer cells can grow to invade and destroy normal tissue around them. And cancerous cells can travel to other parts of the body to form deposits there known as metastasis.
Colon Cancer – Risk factors
Risk of colon cancer may be increased due to factors which may include:
- At any age, colon cancer can be diagnosed, but a majority of people with colon cancer are aged older than 50. The percentage of colon cancer in people aged younger than 50 have been increasing, but doctors aren’t certain why.
- People who are African-Americans have a risk of colon cancer which is greater than people of other races.
- If already having a history of colon cancer or noncancerous colon polyps, a risk of colon cancer in the future is higher.
- Chronic inflammatory diseases of the colon can increase the risk of colon cancer, such as ulcerative colitis and Crohn’s disease.
- Family generations where some gene mutations passed of can increase risk of colon cancer significantly. Only a small percentage of colon cancers are connected to inherited genes. Familial adenomatous polyposis (FAP) and Lynch syndrome are the most common inherited syndromes that increase colon cancer risk, which is also called as hereditary nonpolyposis colorectal cancer (HNPCC).
- Developing a colon cancer is more likely if having a blood relative who has had the disease. The risk is greater if more than one family member has colon cancer or rectal cancer
- Colon cancer and rectal cancer may be linked with a general Western diet, which is low in fiber and high in fat and calories. Research in this area has had results which were mixed. Some studies have found that risk of colon cancer in people who eat diets high in red meat and processed meat is high
- Colon cancer is more likely to develop in people who are inactive. Getting regular physical activity may reduce your risk of colon cancer.
- Risk of colon cancer is high in people with diabetes or insulin resistance.
- People who are obese have risk of colon cancer and dying of colon cancer increased when compared with people who are considered normal weight.
- Smokers may have an increased risk of colon cancer.
- Heavy alcohol usage increases your risk of colon cancer.
- Radiation therapy aimed at the abdomen for treating previous cancers increases the risk of colon cancer.
Screening colon cancer
People with an average risk of colon cancer are recommended by the doctor to consider colon cancer screening around age 50. But people with an increased risk, who have a family history of colon cancer, should consider screening earlier.
Various screening options exist, each with its own advantages and disadvantages. Options should be discussed with the doctor, and which tests are appropriate can be decided together.
Steps can be taken to decrease the risk of colon cancer by making changes in the daily life. Steps can be taken by:
- Eating a variety of fruits, vegetables and whole grains.Vitamins, minerals, fiber and antioxidants, are contained in fruits, vegetables and whole grains which may play a role in cancer prevention. A variety of fruits and vegetables should be selected so that an array of vitamins and nutrients can be taken.
- If choosing to drink alcohol, limit the amount of alcohol to drink shoulf be limited to no more than one drink a day for women and two for men.
- Doctor should be consulted about ways to quit that may work.
- Exercising during most days of the week by trying to get at least 30 minutes of exercise on most days. If been inactive, start gradually and build up to 30 minutes. Also doctor should be contacted before starting any exercise program.
- A healthy weight should be maintained. If having a healthy weight, work to maintain weight by combining a healthy diet with daily exercise. If required to lose weight, doctor should be consulted about healthy ways to achieve the goal. Losing weight should be aimed at slowly by increasing the amount of exercise and reducing the number of calories being eaten.
For decreasing the risk of precancerous polyps or colon cancer, some medications have been found. For a matter of fact, some evidence connects a reduced risk of polyps and colon cancer to frequent use of aspirin or aspirin-like drugs. But what dose and what length of time would be needed is unclear to decrease the risk of colon cancer. Some risks are related to taking aspirin daily, including gastrointestinal bleeding and ulcers.
These options are typically reserved for people with a risk of colon cancer being high. Enough evidence is not present to recommend these medications to people who have an risk of colon cancer being average
If having an increased risk of colon cancer, risk factors should be discussed with the doctor to determine whether preventive medications are safe or not.
Screening for colon cancer
Certain screening tests are suggested by doctors for healthy people with no signs or symptoms in order to look for signs of colon cancer or noncancerous colon polyps. Colon cancer if found at its earliest stage provides the maximum chance for a cure. Screening has been shown to decrease the risk of dying of colon cancer.
People with an average risk of colon cancer may begin screening around age 50 which is usually recommended by the doctor. But people with an increased risk, such as those having a family history of colon cancer or African-American heritage, should consider screening earlier.
Various screening options exist each with its own advantages and disadvantages. Options should be discussed with the doctor, and which tests are appropriate for can be decided together. If using a colonoscopy for screening, removal of polyps can be done during the procedure before they turn into cancer.
Diagnosing colon cancer
If indication of signs and symptoms point to having colon cancer, the doctor may recommend one or more tests and procedures, including:
- A long, flexible and slender tube attached to a video camera and monitor to view the entire colon and rectum is used in colonoscopy. If any areas of doubts are found, the doctor can pass surgical tools through the tube to take tissue samples (biopsies) for analysis and removal of polyps.
- Blood test can not indicate if having a colon cancer. But blood may be tested by the doctor for clues about overall health, such as kidney and liver function tests. Blood may also be tested by the doctor for a chemical sometimes produced by colon cancers known as carcinoembryonic antigen, or CEA. Tracked over the period of time, the level of CEA in the blood may help the doctor in understanding prognosis and whether cancer is responding to treatment.
Determining the extent of the cancer
If colon cancer is diagnosed, the doctor may suggest tests to determine the extent (stage) of the cancer. Staging helps in determining what treatments are most suitable.
Imaging procedures such as abdominal, pelvic and chest CT scans may be included in staging tests. In many cases, the stage of cancer may not be completely determined until after colon cancer surgery.
Roman numerals that range from 0 to IV are used to indicate stages of colon cancer, with the lowest stages indicating cancer that is limited to the lining of the inside of the colon. The cancer is considered advanced and has spread (metastasized) to other areas of the body by the stage IV.
Treatments which are most likely to help depends on specific situation, including the location of cancer, its stage and other health concerns. Surgery is involved for treatment of colon cancer to remove the cancer. Radiation therapy and chemotherapy are other treatments that might also be recommended.
Surgery for early-stage colon cancer
Doctor may recommend a minimally invasive approach to surgery if the colon cancer is small, such as:
- If the cancer is small, localized, fully contained within a polyp and in a very early stage, the doctor may be able to remove it fully during a colonoscopy.
- During colonoscopy the larger polyps might be removed using special tools to remove the polyp and a small amount of the inner lining of the colon in a procedure known as an endoscopic mucosal resection.
- Removal of Polyps which can’t be removed during a colonoscopy may be removed using laparoscopic surgery. The surgeon performs the operation through several small incisions in the abdominal wall in this procedure, inserting instruments with attached cameras that display the colon on a video monitor. Samples might also be taken by the surgeon from lymph nodes in the area where the cancer is located.
Surgery for more advanced colon cancer
The surgeon may recommend below if the cancer has grown into or through the colon:
- During this procedure of partial colectomy, part of the colon is removed by the surgeon that contains the cancer, along with a margin of normal tissue on either side of the cancer. The healthy portions of your colon or rectum are often reconnected by the surgeon. This procedure can generally be done by a minimally invasive approach (laparoscopy).
- An ostomy may be required when it’s not possible to reconnect the healthy portions of the colon or rectum. Creating an opening in the wall of the abdomen from a portion of the remaining bowel for the elimination of stool into a bag that fits securely over the opening is involved in ostomy. Sometimes the ostomy is not permanent, allowing the colon or rectum time to heal after surgery. In certain cases, however, the colostomy may be permanent.
- During colon cancer surgery, removal of nearby lymph nodes is done and tested for cancer.
Surgery for advanced cancer
If the cancer is very advanced or overall health very poor, an operation might be recommended by the doctor to relieve a blockage of the colon or other conditions in order to improve symptoms. This surgery isn’t conducted to cure cancer, but instead for signs and symptoms to be relieved, such as a blockage, bleeding or pain.
In particular cases where the cancer has spread only to the liver or lung but overall health is otherwise good, surgery or other localized treatments might be suggested by the doctor to remove the cancer. Use of chemotherapy can be done before or after this type of procedure. A chance to be free of cancer over the long term is provided by this approach
Drugs used to destroy cancer cells are conducted in chemotherapy. Chemotherapy for colon cancer is generally given after surgery if the cancer is larger or has been spread to the lymph nodes. By this way, cancer cells might be killed by chemotherapy that remain in the body and help decrease the risk of cancer recurrence.
Before an operation also usage of chemotherapy can be done to shrink a large cancer so that it’s easier to remove with surgery.
Symptoms of colon cancer can be relieved with chemotherapy, that can’t be removed with surgery or that has spread to other areas of the body. Sometimes it’s used in combination with radiation therapy.
Powerful energy sources, such as X-rays and protons, to kill cancer cells is used un radiation therapy which might be used to shrink a large cancer before an operation so that the removal can be done more easily.
Radiation therapy might be used to relieve symptoms, such as pain when surgery might not be an option. Sometimes radiation is mixed with chemotherapy.
Targeted drug therapy
Specific abnormalities present within cancer cells is focused by targeted drug treatments. By blockage of these abnormalities, targeted drug treatments can cause cancer cells to die.
Targeted drugs are generally mixed with chemotherapy. Targeted drugs are generally reserved for people with advanced colon cancer.
A drug treatment that uses immune system to fight cancer is known as immunotherapy. The body’s disease-fighting immune system may not attack the cancer because proteins are developed by the cancer cells that blind the immune system cells from recognizing the cancer cells. By interfering with that process, immunotherapy works.
Immunotherapy is generally reserved for advanced colon cancer. Cancer cells might be tested by the doctor to see if they’re likely to respond to this treatment.
Supportive (palliative) care
A specialized medical care that focuses on providing relief from pain and other symptoms of a serious illness is known as palliative care. A team of doctors, nurses and other specially trained professionals provide palliative care that work with you, your family and your other doctors to provide an extra layer of support that complements the ongoing care.
The goal of the palliative care teams is to improve the quality of life for people with cancer and their families. This type of care is offered alongside curative or other treatments being received.
Palliative care when used along with all of the other suitable treatments, people with cancer may feel better and live longer.