What is colon cancer?
Colorectal cancer (CRC) occurs when malignant cells develop inside your colon or rectum. These cells produce abnormal growths called polyps, which may become cancerous over time. Polyps may not cause any symptoms, however if they become cancerous, then they can lead to bleeding problems, pain, and other symptoms. Depending on where these cancer cells arise, they may move through your body and spread to other parts of the body. Colon Cancer can occur at any age. People who have had polyps removed because of previous polyp removal from their colon, or have a family history of CRC, are more likely to get this type of cancer than someone who does not fit those criteria.
How do people get colon cancer?
Most cases of colon cancer start off as polyps, small growths of tissue, covered by normal colon mucosa. As long as the polyps remain small and don’t change in size, they’re unlikely to ever turn into cancer. However, if you have several polyps, they may eventually begin to grow larger and spread throughout your colon. Sometimes they may bleed, causing blood loss and diarrhea. If you notice changes in your stool, and if you have severe abdominal cramps, you should contact your doctor immediately. You may think that you have just eaten something unusual, like broccoli or cauliflower. But it’s possible that you ate food that contains pieces of polyps or cancer cells that passed into your intestinal tract.
If you are diagnosed with colorectal cancer, your doctors will obtain tumor samples as well as lymph node samples to see if the cancer has spread outside of your colon. Your cancer treatment plan will depend on your stage of disease, how advanced it is, and how much of your colon is involved.
Treatment for colon cancer
There are different types of treatment for colon cancer you could receive, depending upon the stage of the disease. One option is surgery or removing the entire area of colon affected by the tumor. Another option is chemotherapy, which involves using drugs to kill cancer cells. Chemotherapy may be combined with radiation therapy, which uses high doses of ionizing radiation to destroy damaged DNA in cancer cells. Radiation therapy can either be external beam radiation, using a machine outside your body that focuses beams of X-rays onto the surface of the tumor, or brachytherapy, which delivers radioactive seeds directly to the tumor site via catheterization.
Another option is immunotherapy, which attempts to make your immune system recognize and attack cancer cells rather than leave them alone.
Apar from chemotherapy, other treatments methods are:
Surgery is mostly used for colon cancer treatment. Surgery removes the entire tumor and nearby lymph nodes. Depending on how much surrounding tissue is involved, surgery may require removal of part or all of the affected organs, depending on the size and location of the tumor. The surgeon makes small incisions at the top of the abdomen to view the inside of the abdominal cavity and remove the tumor. Most people have a single surgery to completely remove the cancer.
After surgery, if the cancer was located near the large intestine, the surgeon will make an opening through the wall of the colon (colonoscopy) and use special tools inserted through the opening to look for any remaining cancer cells or precancerous polyps.
If cancer cells were found near the rectum, additional process may be required to completely remove them. These procedures may include removing some or all of the lining of the rectal tube and cutting away any abnormal tissue.
Second type of surgery
A second type of surgery, called an abdominoperineal resection, removes the whole bowel along with a section of skin from the bottom of the pelvis.
If the cancer involves only part of the colon or if the cancer has spread to the colon from somewhere else, the doctor may recommend chemotherapy. Chemotherapy uses drugs to kill cancer cells. The types of chemotherapy depend on what type of cancer the person has. Different chemotherapy medications work best on different types of cancer. To reduce the risk of side effects from chemotherapy, the doctor gives the medications in cycles separated by short breaks.
In some cases, especially if the colon cancer is early, the doctor may suggest radiation therapy instead of chemotherapy. Radiation works by damaging the DNA of the cancer cells. In addition to killing the cancer cells, this damage also kills normal cells, such as colon or nearby organs.
After first operation, it is possible that cancer might come back. There is some evidence that chemotherapy and radiation therapy have long-term benefits.
Radiotherapy delivers high doses of radiation directly to the tumor, aiming to destroy cancer cells without affecting healthy tissue.
The goal of radiotherapy is to stop the growth of new cells while minimizing damage to the adjacent healthy tissue. Because the high energy x-rays used in radiotherapy travel faster than visible light, they can penetrate deeply into the body and damage the soft tissue. If the radiation dose is too strong, the damage may cause severe pain, nausea, vomiting, diarrhea, hair loss, fatigue etc. However, many people tolerate radiotherapy well.
Uses of Radiation Therapy
Radiotherapy is a treatment method which is used to treat cancers of the lung, breast, prostate etc. Before surgery also, radiotherapy is used to reduce the size of tumor. Often, the treatment begins in one area, and then moves to other places that are close to the first area.
There are two basic forms of external beam radiotherapy. IMRT is a type of radiation therapy which aims to deliver higher doses of radiation to the target area while protecting the other cells. Another technique is stereotactic radiosurgery which focuses a series of beams onto a small spot in the brain, spinal cord, chest, liver, kidney, pancreas or elsewhere.
Internal radiation therapy uses radioactive material to deliver radiation to the body from within. Brachytherapy uses seeds, wires, pellets or capsules containing radioactive material. External brachytherapy treats cancer in the reproductive organs or pelvic muscles.
Screening tests for colon cancer
The best way to detect colon cancer early is by performing screening tests. There are two types of testing that are commonly performed—a fecal occult blood test and a sigmoidoscopy or colonoscopy. Each of these tests checks for blood in your stool, which would indicate that cancer cells have broken through the surface of the colon wall and entered your bloodstream. Blood in your stool often comes from benign tumors, ulcers, diverticulosis (large pouches), Crohn’s disease, and hemorrhoids, but sometimes it indicates cancer.
A sigmoidoscopy is similar to a standard colonoscopy except that it only examines the lower half of the colon. In contrast, a colonoscopy looks at everything from the cecum (the beginning of the colon) to the rectum. Both procedures can identify precancerous lesions, cancers, and other abnormalities of the colon, although neither procedure is 100% accurate. Most importantly, both procedures are uncomfortable. Many people find that they aren’t able to tolerate having a tube down their throat and into their intestines.
Prevention of colon cancer
There are ways to prevent colon cancer, especially if you’ve already had polyps removed from your colon. First of all, you’ll want to adhere to a low-fat diet. Since high fat intake increases inflammation levels in the body. Secondly, you’ll want to cut back on alcohol consumption. Alcohol increases the production of acetaldehyde in the body which can cause colon cancer. Also, try to avoid tobacco. Tobacco use causes chronic irritation, and research shows that it may increase your risk of developing colon cancer.