Rajen's Easytips: COLON (COLORECTAL) CANCER

COLON (COLORECTAL) CANCER

1. What is colon cancer?

The human colon is a muscular, tube-shaped organ measuring about 4 feet long.
It extends from the end of your small bowel to your anus, twisting and turning through your abdomen (belly).
The colon has 3 main functions.

To digest and absorb nutrients from food
To concentrate fecal material by absorbing fluid (and electrolytes) from it
To store and control evacuation of fecal material

The right side of your colon plays a major role in absorbing water and electrolytes, while the left side is responsible for storage and evacuation of stool.
Most colon cancers are adenocarcinomas—tumors that develop from the glands lining the colon’s inner wall.
These tumors are sometimes referred to as colorectal cancer, reflecting the fact that the rectum, the end portion of the colon, can also be affected.

2. What are the causes of colon cancer?

Most colorectal cancers arise from adenomatous polyps—clusters of abnormal cells in the glands covering the inner wall of the colon.
Over time, these abnormal growths enlarge and ultimately degenerate to become adenocarcinomas.
People with any of several conditions known as adenomatous polyposis syndromes have a greater-than-normal risk of colorectal cancer.
In these conditions, numerous adenomatous polyps develop in the colon, ultimately leading to colon cancer.
The cancer usually occurs before age 40 years.
Adenomatous polyposis syndromes tend to run in families.
Such cases are referred to as familial adenomatous polyposis (FAP).
Another group of colon cancer syndromes, termed hereditary nonpolyposis colorectal cancer (HNPCC) syndromes, also run in families.
In these syndromes, colon cancer develops without the precursor polyps.
HNPCC syndromes are associated with a genetic abnormality.
This abnormality has been identified, and a test is available.
People at risk can be identified through genetic screening.
Once identified as carriers of the abnormal gene, these people require counseling and regular screening to detect precancerous and cancerous tumors.
HNPCC syndromes are sometimes linked to tumors in other parts of the body.
Also at high risk for developing colon cancers are people with any of the following:

Ulcerative colitis or Crohn colitis (Crohn disease)
Breast, uterine, or ovarian cancer now or in the past
A family history of colon cancer

The risk of colon cancer increases 2-3 times for people with a first-degree relative (parent or sibling) with colon cancer.
The risk increases more if you have more than one affected family member, especially if the cancer was diagnosed at a young age.
Whether diet plays a role in developing colon cancer remains under debate.
The belief that a high-fiber, low-fat diet could help prevent colon cancer has been questioned.
Studies do indicate that exercise and a diet rich in fruits and vegetables can help prevent colon cancer.
Obesity has been identified as a risk factor for colon cancer.
Recent studies have suggested that estrogen replacement therapy and non-steroidal anti-inflammatory drugs such as aspirin may reduce colorectal cancer risk.
Cigarette smoking has been definitely linked to a higher risk for colon cancer.

3. What are the symptoms of colon cancer?

In its early stages, cancer usually has no symptoms, but eventually a malignant tumor will grow large enough to be detected.
As it continues to grow, it may press on nerves and produce pain, penetrate blood vessels and cause bleeding, or interfere with the function of a body organ or system.
Cancer of the colon and rectum can exhibit itself in several ways.
If you have any of these symptoms, seek immediate medical help.
You may notice bleeding from your rectum or blood mixed with your stool.
People commonly attribute all rectal bleeding to hemorrhoids, thus preventing early diagnosis owing to lack of concern over "bleeding hemorrhoids."
Rectal bleeding may be hidden and chronic and may show up as an iron deficiency anemia.
It may be associated with fatigue and pale skin.
It usually, but not always, can be detected through a fecal occult (hidden) blood test, in which samples of stool are submitted to a lab for detection of blood.
If the tumor gets large enough, it may completely or partially block your colon.
Abdominal distension: Your belly sticks out more than it did before without weight gain.
Abdominal pain: This is rare in colon cancer.
One cause is tearing (perforation) of the bowel.
Leaking of bowel contents into the pelvis can cause inflammation (peritonitis) and infection.
Unexplained, persistent nausea or vomiting
Unexplained weight loss
Change in frequency or character of stool (bowel movements)
Small-caliber (narrow) or ribbon-like stools
Sensation of incomplete evacuation after a bowel movement
Rectal pain rarely occurs with colon cancer and usually indicates a bulky tumor in the rectum that may invade surrounding tissue.
Studies suggest that the average duration of symptoms (from onset to diagnosis) is 14 weeks.
There is no association between overall duration of symptoms and the stage of your tumor.

4. When should you seek medical care for colon cancer?

Bright red blood on the toilet paper, in the toilet bowl, or in your stool when you have a bowel movement
Change in the character or frequency of your bowel movements
Sensation of incomplete evacuation after a bowel movement
Unexplained or persistent abdominal pain or distension
Unexplained weight loss
Unexplained, persistent nausea or vomiting
Copious bleeding from your rectum
Unexplained severe pain in your belly or pelvis (groin area)
Vomiting and inability to keep fluids down

5. Exams and Tests

If you are having rectal bleeding or changes in your bowel movements, you will undergo tests to determine the cause of the symptoms.
Your health care provider may insert a gloved finger into your rectum through your anus.
This test, called a digital rectal exam, is a quick screen to make sure that any bleeding is actually coming from your rectum.
This is not painful, but it is mildly uncomfortable for some people. It takes only a few seconds.
You may have a test called a colonoscopy which allows a specialist in digestive diseases (a gastroenterologist) to look at the inside of your colon.
This test looks for polyps, tumors, or other abnormalities.
Colonoscopy is an endoscopic test which means that a thin, flexible plastic tube with a tiny camera on the end will be inserted into your colon via your anus.
As the tube is advanced further into your colon, the camera sends images of the inside of your colon to a video monitor.
Colonoscopy is an uncomfortable test for most people.
You will first be given a laxative solution to drink that will clear most of the fecal matter from your bowel.
You will be allowed nothing to eat before the test.
Whenever possible, you will be given medication before the procedure to relax you and relieve the discomfort.
Flexible sigmoidoscopy is similar to colonoscopy but does not go as far into the colon.
It uses a shorter endoscope to examine the rectum, sigmoid (lower) colon, and most of the left colon.
Air-contrast barium enema is a type of x-ray that can show tumors.
Before the x-ray is taken, a liquid is introduced into your colon and rectum via your anus.
The liquid contains barium, which shows up solid on x-rays.
This test highlights tumors and certain other abnormalities in the colon and rectum.
Other types of contrast enemas are available.
Air-contrast barium enema frequently detects malignant tumors, but it is not as effective in detecting small tumors or those far up in your colon.
If a tumor is identified in the colon or rectum, you will probably undergo CT scan of your abdomen and a chest x-ray to make sure the disease has not spread.

6. Medical treatment of colon cancer

The primary treatment of colon cancer is to surgically remove part or your entire colon.
Suggestive polyps, if few in number, may be removed during colonoscopy.
Chemotherapy after surgery can prolong survival for people whose cancer has spread to nearby lymph nodes.
Radiation treatment after surgery does not help people with colon cancer, but it does prolong survival for people with rectal cancer.
Given before surgery, radiation may reduce tumor size.
This can improve the chances that the tumor will be removed successfully.
Radiation before surgery also appears to reduce the risk of the cancer coming back after treatment.

7. Surgery

Surgery is the cornerstone of treatment for colon cancer.
You may need to have the entire colon removed or only part of your colon.
How much of your colon has to be removed depends on the location and particular characteristics of your tumor.
Sometimes only a polyp is cancerous, and removal of the polyp may be all that is necessary.
Surgery may also be done to relieve symptoms when the cancer has caused a bowel obstruction.
The usual procedure is bypass for obstructions that cannot be cured.
Sometimes a colorectal tumor can be surgically removed only by creation of a permanent colostomy.
This is a small, neatly constructed opening in your belly.
As part of the surgery, the colon that is left in your body is attached to this opening.
Fecal matter will exit your body through this hole instead of through your anus.
You will wear a small appliance or bag, which attaches to your skin around the opening and collects fecal matter.
The bag is changed regularly to prevent skin irritation and odor.
Your surgeon will attempt to preserve your rectum and anus whenever possible.
Several surgical procedures have been developed that can preserve evacuation of fecal material through the anus whenever possible.
Whether you need a colostomy depends on individual circumstances.
In general, tumors on the right side of your colon or on the left side above the level of the rectum may not call for colostomy.
Tumors in the rectum may require removal of the rectum and anal sphincter and construction of a permanent colostomy to divert your bowel.

8. Follow-up

Once your cancerous colon has been removed and you receive any other treatment recommended by your cancer care team, you will see your gastroenterologist or cancer specialist (oncologist) regularly for follow-up visits.
These visits will allow your team to see if the cancer has spread and to detect newly formed cancers.
These follow-up visits should include, at minimum, the following:
Colonoscopy within 3 months after your surgery
Colonoscopy 1 year after surgery and every 3 years after that.
Test for occult (hidden) blood in your stool every year, followed by colonoscopy if the test result is positive
A screening tool—measurement of carcinoembryonic antigen (CEA) level—is available to test for cancer recurrence following cancer surgery.
CEA is a protein normally found in trace amounts in your bloodstream but is present in increased amounts in people with colon cancer.
It is referred to as a tumor marker.
Blood CEA levels should be measured before colon cancer surgery and then at intervals of 2-3 months.
Increasing levels of serum CEA may indicate that colon cancer has come back and that you should seek further evaluation.
Once you have had several blood tests with negative results, you probably don't need to continue the tests indefinitely.
However, no one is sure how long you should continue to have the tests.
You should discontinue screening tests if you have other health problems that make you unfit to undergo treatment for a recurrence of your colon cancer.

9. Recovery

Recovery from colon cancer depends on the extent of your disease before your surgery.
If your tumor is limited to the inner layers of your colon, you can expect to live 5 years or more.
If cancer has spread to your lymph nodes adjacent to the colon, the chance of living 5 years is 65%.
If the cancer has already spread to other organs, the chance of living 5 years drops to 8%.
If the cancer has reached your liver but no other organs, removing part of your liver may prolong your life.

10. Prevention

Your best prevention is to detect colon cancer and treat it early in its formation.
People, who have regular screening for colon cancer, including fecal occult blood tests, sigmoidoscopy or colonoscopy, and polyp removal, greatly reduce their risk of having a colorectal cancer.
Screening for colon cancer is recommended in people older than 50 years who have an average risk for the disease and in people aged 40 years and older who have a family history of colorectal cancer.
One of the following screening techniques is used:

Fecal occult blood testing every year combined with flexible sigmoidoscopy every 5 years
Double-contrast barium enema every 5-10 years
Colonoscopy every 10 years: Colonoscopy remains the most sensitive test for detecting colon polyps and tumors.

Once polyps have been identified, they should be removed.
After you have had polyps, even one polyp, you should begin to have more frequent colonoscopies.
Appropriate preventive screening for people with ulcerative colitis includes the following:
Colonoscopy every 1-2 years in the following cases:

If you have known you have the disease for 7-8 years
If the cancer involves the entire colon
Beginning 12-15 years after the diagnosis of left-sided colitis
Random colon biopsies taken during colonoscopy

People with ulcerative colitis in whom biopsies show premalignant changes should undergo surgical removal of their colons.

11. Food and lifestyle changes

Quit smoking as it has been clearly linked with higher risk of cancer.
Take an aspirin or baby aspirin every day.
Because of potential side effects, you should consult your doctor first.
Take a safe dose of folic acid (for example, 1 mg) every day.
Engage in physical activity every day.
Eat a variety of fruits and vegetables every day.
Curcumin, a common spice derived from turmeric, is a powerful anti-inflammatory compound that inhibits genes involved in the growth and spread of cancer.
It also creates a gastrointestinal environment favourable to colon health by reducing levels of natural secretions that contribute to colon cancer risk.
Garlic reduces carcinogenic potential of compounds such as nitrosamines and exerts anti-proliferative effects.
Aged garlic extract reduces the formation of pre-cancerous adenomas.
Key compounds in ginger limit the oxidative damage to cells caused by free radicals.
They also lower levels of cytokines that provoke an inflammatory response.
This dual action inhibits initiation of carcinogenesis and limits expansion of existing malignancies.
Red meat consumption should be avoided as it leads to a higher risk of colorectal cancer.
Green tea extract is known to have anti-cancer actions on growth, survival, angiogenesis and metastatic processes of cancer cells.
Heavy drinking increases your risk of colorectal cancer.
Exercise cuts the risk of colon cancer and polyps, and sedentary living increases it.
Cardio work speeds up gut transit, the time taken for digested food to pass through the colon, and reduces the time carcinogens are around to mutate healthy cells.