Colon cancer is the growth of cancer in the large intestine.
Cancer occurs when cells in the body divide without control or order. If cells keep dividing, a mass of tissue forms, called a growth or tumor. The term cancer refers to malignant tumors. They can invade nearby tissue and spread to other parts of the body.
The cause of colon cancer is unknown.
Factors that may increase your risk of colon cancer include:
Age: 50 or older
Diets high in fat, low in
fiber
History of
polyps
, which are non-cancerous growths in the colon and rectum
Hereditary conditions such as
familial polyposis
or Lynch syndromePersonal history of colorectal cancerFamily history of colon or rectal cancer, especially a parent, sibling, or child
History of
ulcerative colitis
or
Crohn’s disease
Other risk factors include:
ObesityHigh body mass index
(BMI)Physical inactivityDiabetesSmokingHeavy alcohol intakeDiet high in red meats and low in fishColon cancer often does not have any symptoms. However, some symptoms associated with colon cancer include:
A change in bowel habits such as
diarrhea,
constipation, or feeling that the bowel does not empty completely—Lasting for more than a few days in people aged 50 and olderBright red or very dark blood in the stoolStools that are narrower than usualAbdominal discomfort, such as frequent gas pains, bloating, fullness, and/or crampsUnexplained weight lossFeeling tired frequentlyThese may also be caused by other, less serious health conditions. Anyone experiencing these symptoms should see a doctor.
The doctor will ask about your symptoms and medical history. A physical exam will be done.
Tests to screen for cancer or precancerous polyps include:
Your rectum may need to be checked for lumps or growths. This can be done with a digital rectal exam.
Your waste products may need to be checked. This can be done with a fecal occult blood test.Your rectum and colon may need to be examined. This can be done with:
ColonoscopySigmoidoscopy
You may need to have pictures taken of your bodily structures. This may include: A barium enema to create a better imageComputed tomography (CT) colonography
Additional tests may be done to confirm the presence of cancer, determine what stage the cancer is in, and/or determine if the cancer has spread:
You may need to have your bodily fluid tested to check for anemia and markers of cancer in the blood. This can be done with blood tests.You may need to have tissue samples or polyps removed. This can be done with: Biopsy—The removal of colon or rectal tissue to be tested for cancerPolypectomy—The removal of a polyp during a sigmoidoscopy or colonoscopyYou may need to have additional pictures taken of your bodily structures. This can be done with: CT scanPositron emission tomography (PET)/CT scanTransrectal ultrasoundTreatment depends on the stage of the cancer but may include:
Surgery is the main treatment. It requires
removal
of the cancerous tumor and nearby colon tissue. Depending on the size and location of the tumor, the surgery may be done by:
Laparoscopy—Removal of early-stage cancer.Open surgery—To remove tumors, colon tissue, and sometimes nearby lymph nodes. The surgeon will also look for additional cancer in the colon during the surgery.
In some cases, the tumor and nearby healthy colon tissue will be removed. Healthy tissue is removed in case the cancer has begun to spread. The removal of a part of the colon is called a
hemicolectomy. In most cases, the remaining healthy portions of the colon are reconnected. Sometimes, the end of the healthy colon is temporarily or permanently attached to an
opening in the abdomen. This is called a
colostomy.
It allows body waste to pass out of the body if the colon cannot do so.
Radiation therapy is the use of
radiation
to kill cancer cells and shrink tumors. It is directed at the site of the tumor from a source outside the body.
This therapy is aimed at the immediate area of the cancer.
This
therapy
uses drugs to kill cancer cells. It may be given in many forms, including pill, injection, and catheter. The drugs enter the bloodstream and travel through the body killing mostly cancer cells. They can also kill some healthy cells.
This therapy is systemic, meaning it affects your entire body.
If you are diagnosed with colon cancer, follow your doctor's
instructions.
The causes of most cancers are not known. However, it is possible to prevent many colon and rectal cancers by finding and removing polyps that could become cancerous. Beginning at age 50, both men and women at average risk should follow one of five screening options:
Yearly fecal occult blood test or fecal immunochemical testColonoscopy every 10 yearsFlexible sigmoidoscopy every five yearsX-rays of the colon and rectum with double-contrast barium enema every five yearsCT colonography every five yearsBe sure to discuss these cancer screening tools with your doctor to see which option is best for you.
People with any of the following risk factors should begin colon and rectal cancer screening at age 40 or earlier and/or undergo screening more often:
Strong family history of colon or rectal cancer or polypsKnown family history of hereditary colon or rectal cancer syndromesPersonal history of colon and rectal cancer or adenomatous polypsPersonal history of chronic inflammatory bowel diseaseThere are also lifestyle changes that may reduce your risk of colon cancer, such as:
Not smokingBeing physically active, including, exercising at least 30 minutes on most days of the weekMaintaining a healthy weight
Eating a
high-fiber diet containing fruits, vegetables, grains, and legumes Making other changes to your diet, like eating plenty of fruits and vegetables, not eating a lot of red meat, and not abusing alcoholLast reviewed September 2012 by Mohei Abouzied, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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