Cancer - colorectal
Colorectal cancer, cancer of the colon and rectum, is the second leading cause of cancer mortality in America. Colon cancer occurs in the large intestine. If the cancer is in the last 6 inches of the colon (the rectum), it is considered rectal cancer. The colon is the lower part of the digestive system, which processes food for energy and rids the body of solid waste. Together, these cancers are referred to as colorectal cancers. Most colorectal cancers begin as benign adenomas, or polyps that grow on the inner lining of the colon or rectum. These growths spread very slowly, taking from 10 to 20 years to become cancerous. Regular screening tests can identify and remove polyps before they become cancerous. Once colorectal cancer is diagnosed, the prognosis depends on how much the cancer has spread.
Most cases of colorectal cancer occur in people over 50. Although colorectal cancer is responsible for thousands of deaths every year, it is highly treatable if caught early.
Signs and Symptoms
Unfortunately, most people with colorectal cancer do not have any symptoms in the early stage of the disease. That is why screening tests, such as a colonoscopy, are so important.
In general, signs and symptoms of colorectal cancer can include the following:
- Changes in bowel habits
- Blood in the stool
- Problems related to blood loss (anemia, weakness, fatigue, shortness of breath, pounding or racing heart, chest pain, and intolerance to exercise)
- Abdominal discomfort (frequent gas, bloating, fullness, cramps, and pain)
- Unexplained weight loss
- Pain with bowel movement
- Feeling that your bowel does not empty completely
These symptoms may be caused by colorectal cancer or by other conditions such as infections, hemorrhoids, and inflammatory bowel disease. It is important to tell your doctor about any of these symptoms.
More than half of all colorectal cancers occur without any known cause. Studies also suggest that genetics may play a role. Some people with colorectal cancer carry specific genetic mutations or have relatives with the condition. Those with a family history of specific genetic syndromes, such as familial adenomatous polyposis, Lynch syndrome, juvenile polyposis, and Peutz-Jeghers syndrome, are also at an increased risk of developing colorectal cancer. About 25% of people have a familial component. Smoking and eating a high-fat diet also raise the risk of developing cancer.
Risk factors for colorectal cancer include:
- Age (being over 50)
- Having colorectal cancer previously
- Having a history of adenomatous polyps
- Family history of colorectal cancer
- Eating a high-fat diet
- Prolonged consumption of red and processed meat
- Being overweight
- Heavy use of alcohol
- Having inflammatory bowel disease (such as Crohn disease and ulcerative colitis)
- Having diabetes
- Previous endometrial or ovarian cancer
- Women undergoing radiation for gynecologic cancer
You doctor will take a complete medical history, perform a physical exam, and may order one or more tests to diagnose colorectal cancer including sigmoidoscopy, colonoscopy, and barium enema. During a sigmoidoscopy or a colonoscopy, your doctor removes a sample of tissue (called a biopsy) from the colon or rectum and examines it under a microscope to detect abnormal growths. If cancer is evident, your doctor will perform a series of tests (chest x-ray, abdominal CT scan, and blood tests to check liver function) to see if the cancer has spread and to help determine the stage (or extent) of the disease. Stages of colorectal cancer include:
- Stage 0: The earliest stage; cancer is found only in the innermost lining of the colon and/or rectum.
- Stage 1: Cancer has grown through the innermost lining but hasn't spread beyond the colon wall or rectum.
- Stage 2: Cancer has spread to deeper layers of the wall of the colon or rectum, but not the lymph nodes.
- Stage 3: Cancer has spread to nearby lymph nodes but not to other parts of the body.
- Stage 4: Cancer has spread to other parts of the body, such as the liver and lungs.
Colorectal cancer is highly preventable, even curable, when detected early. Regular screening for colorectal cancer detects polyps before they become cancerous. Studies show that colonoscopies, in particular, prevent up to 19% of colorectal cancer deaths. Current guidelines recommend these screening options, starting at age 50 for people who have an average risk of colon cancer:
- Annual fecal occult blood testing, tests for blood in the stool
- Stool DNA testing, tests for DNA markers shed by cancer cells of precancerous polyps
- Flexible sigmoidoscopy, every 5 years, examination of the rectum and lower colon using a lighted instrument
- Colonoscopy, every 10 years (if previous colonoscopy was normal and no other risk factors are present), examination of the rectum and entire colon using a lighted instrument
- Double contrast barium enema, every 5 years (assuming all previous tests were normal and no other risk factors are present), examination using a series of x-rays that reveal outlines of the colon and rectum
- Virtual colonoscopy (CT colonography), every 5 years (assuming all previous tests were normal and no other risk factors are present), uses a CT scan to take images of the colon
Those with a family history of colorectal cancer should have a colonoscopy every 3 to 5 years, starting at least 10 years before the age of the relative at the time of his or her diagnosis.
Diet and Exercise
Eating plenty of fruits and vegetables, as well as foods rich in omega-3 fatty acids (such as salmon and halibut), folate (such as whole grains and leafy green vegetables), and calcium (such as sea vegetables and kale), can help reduce the risk of colorectal cancer. Limiting alcohol consumption, quitting smoking, and reducing the intake of high-fat and fried foods, particularly red meats, may also protect against developing colorectal cancer.
Maintaining a proper weight and exercising regularly also cuts your risk of developing colorectal cancer. Even small amounts of exercise on a regular basis are protective. The American Cancer Society recommends at least 30 minutes of physical activity on most days.
Surgery to remove the part of the colon containing the tumor is the primary treatment. Depending on the stage of the cancer, surgery is followed with chemotherapy. If the tumor is particularly large, you may need radiation before or after surgery.
Some medications or supplements may help prevent the development of polyps or colorectal cancer. Making lifestyle changes, especially eating less red meat, losing weight, quitting smoking, and getting more exercise, may help prevent the disease; even in people with a family history of the condition.
Even if you have no family history of colorectal cancer, an unhealthy lifestyle can increase your risk of developing the disease. Some experts believe making healthy lifestyle changes may lower the risk of developing colorectal cancer by as much as 70%.
Many studies support the association between colorectal cancer and lack of exercise and obesity. Research continues to show that exercise and low-calorie diets may help prevent colorectal cancer.
A large, population-based study of men and women in Hawaii found that the following lifestyle factors were linked with colorectal cancer:
- Heavy alcohol consumption
- History of diabetes
- Frequent constipation
- High calorie diet
- Physical inactivity
- Low vegetable fiber intake (evidence here is mixed)
- High levels of insulin (hormone that controls blood sugar levels)
- Meat consumption
After surgery, chemotherapy (the use of anticancer drugs to destroy cancer cells) may be given to kill any cancerous cells that remain in the body. Chemotherapy controls the spread of the disease and improves survival rates over time. Doctors may use the following chemotherapeutic medications alone or in combination to treat colorectal cancer:
- FOLFOX. A type of combination chemotherapy used to treat colorectal cancer. It includes the drugs fluorouracil, leucovorin, and oxaliplatin.
- Camptosar. Used when colon cancer has spread (metastasized) or returned; may be combined with other drugs.
- Bevacizumab (Avastin). Used when colorectal cancer has spread, it starves tumors of blood and oxygen.
- Cetuximab (Erbitux). Used when colorectal cancer has spread despite the use of another drug, irinotecan (Camptosar), or when people cannot take Camptosar alone. It works to stop cancer cells from reproducing.
- Panitumumab (Vectibix). Used when colorectal cancer has spread despite chemotherapy. It works similar to Erbitux.
Researchers are investigating whether long-term use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) plays a role in the prevention and treatment of colorectal cancer. Preliminary studies are promising. However, these drugs have risks of their own, including an increased chance of stomach bleeding. NSAIDs may also increase risk of heart problems.
Surgery and Other Procedures
Surgery is the treatment of choice for colorectal cancer, and is best when the disease is found at an early stage. Polyps can be removed during a colonoscopy, before becoming cancerous. When colon cancer is present, a person may need a partial or total removal of the colon (colectomy) and rectum (rectal resection). It depends how severe the cancer is, where it is located, and whether or where it has spread. During surgery, the surgeon also examines other organs for signs of cancer. If cancer has spread to the liver, a portion of the liver may be removed as well.
After removing the tumor and nearby tissue, the surgeon reconnects the healthy portions of the colon or rectum. If the healthy parts of the colon or rectum cannot be reconnected, a temporary or permanent opening (stoma) is made through the wall of the abdomen to provide a path for waste material to leave the body. This procedure is called a colostomy. Radiation may also be used before or during surgery to shrink the tumor, and it may be recommended after surgery to reduce the risk of recurrence. After surgery, colonoscopies are performed every 3 to 6 months for 3 years.
Nutrition and Dietary Supplements
Colorectal cancer should never be treated with nutrition and dietary supplements alone. However, a comprehensive treatment plan for colorectal cancer may include a range of complementary and alternative (CAM) therapies. Some supplements and herbs may help reduce side effects from conventional medications. Others may help reduce the risk of developing colorectal cancer. Mind body therapies such as meditation, relaxation techniques, yoga, and qi gong may reduce the effects of stress and enhance your response to treatment. Ask your team of health care providers about the best ways to incorporate these therapies into your overall treatment plan.
Always tell your doctor about the herbs and supplements you are using or considering using. Some supplements may interfere with conventional cancer treatments, including chemotherapy.
Follow these nutritional tips for overall health:
- Eat antioxidant foods, including fruits (such as blueberries, cherries, and tomatoes), and vegetables (such as squash and bell peppers). Antioxidants help protect against cancer.
- Avoid refined foods, such as white breads, pastas, and especially sugar.
- Eat foods rich in fiber, especially cruciferous vegetables, such as broccoli, cauliflower, and cabbage.
- Eat fewer red meats and more cold-water fish, tofu (soy, if no allergy), or beans for protein. Studies suggest that people who eat less meat are at lower risk of developing colorectal cancer. Quality protein sources, such as organic eggs, whey, and vegetable protein shakes, can be used to help gain muscle mass and prevent wasting that can sometimes be a side effect of cancer therapies.
- Use healthy oils, such as olive oil or coconut oil.
- Eliminate trans-fatty acids, found in commercially-baked goods such as cookies, crackers, cakes, French fries, onion rings, donuts, processed foods, and margarine.
- Reduce saturated fats, especially red meat.
- Avoid caffeine and other stimulants, alcohol, and tobacco.
- Drink 6 to 8 glasses of filtered water daily.
- Exercise at least 30 minutes daily, 5 days a week.
These supplements may also help reduce risk of developing colorectal cancer:
- A multivitamin daily, containing the antioxidant vitamins A, C, E, the B-complex vitamins, and trace minerals, such as magnesium, calcium, zinc, and selenium.
- Omega-3 fatty acids, such as fish oil, 1 to 2 capsules or 1 to 3 tablespoons oil daily. Population studies suggest that omega-3 fatty acids may reduce the risk of developing colon, breast, or prostate cancer. Preliminary studies suggest that fish oil might help reduce the growth rate of colon cancer cells. More research is needed. Ask your doctor before taking high doses of supplemental fish oil, which can increase the risk of bleeding, especially if you are taking blood-thinning medications, such as warfarin (Coumadin) or aspirin. Cold-water fish, such as salmon or halibut, are good sources to add to your diet.
- Probiotic supplement (containing a mixture of organisms including Lactobacillus acidophilus), 5 to 10 billion CFUs (colony forming units) a day. These "friendly" bacteria help keep the digestive tract healthy. Preliminary evidence suggests that probiotics might help reduce recurrence of tumors in people who have had surgery to remove colon cancer. Refrigerate your probiotic supplements for best results.
- Calcium, 1,000 to 1,200 mg daily. Calcium binds to ionized fatty acids and secondary bile acids to reduce mucosal toxicity and/or directly reduce intestinal proliferation. In fact, studies show a 14% reduction in risk among subjects with the highest versus the lowest categories of intake.
- Vitamin D. Preliminary studies suggest that vitamin D supplementation alone may be associated with up to a 50% reduction in colon cancer risk. More research is needed. Dosing guidelines for vitamin D have been a subject of much controversy with some experts recommending conservative dosing of 400 to 1000 IU per day for adults while others hold that much higher doses are necessary. Also some megadose vitamin D supplements have now appeared in health food stores. High levels of vitamin D may be particularly risky in patients with sarcoidosis, histoplasmosis, parathyroid disease and some types of lymphomas. The only way to determine appropriate dosing is to have your doctor test your vitamin D levels. Speak to your doctor about proper amounts of vitamin D for your particular case.
Herbs are a way to strengthen and tone the body's systems. However, herbs alone should never be used to treat colon cancer, and you should talk to your doctor before taking any herbs if you are being treated for colon cancer. Some herbs and supplements can interfere with chemotherapy and other treatments. You may use herbs as dried extracts (capsules, powders, or teas), glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless otherwise indicated, make teas with 1 tsp. herb per cup of hot water. Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for roots. Drink 2 to 4 cups per day. You may use tinctures alone or in combination as noted.
- Green tea (Camellia sinensis) standardized extract, 250 to 500 mg daily. Green tea contains antioxidants and can help boost the immune system. It may help prevent cancer, although studies have not been able to prove that. Use caffeine-free products. You may also prepare teas from the leaf of this herb. Green tea can worsen symptoms in people with Glaucoma and may be contraindicated in certain people who suffer from liver disease and osteoporosis; speak with your physician.
- Reishi mushroom (Ganoderma lucidum) standardized extract. Animal studies suggest it may have cancer-fighting properties. One study in humans found it strengthened the immune system response, which is often weakened during chemotherapy. Reishi mushroom may interact with medications that slow blood clotting (anticoagulant/antiplatelet drugs).
- Maitake mushroom (Grifola frondosa) standardized extract (D-fraction). Preliminary studies suggest it may help the body fight cancer, although more research is needed to know for sure.
- Turmeric (Curcuma longa) standardized extract. Turmeric or curcumin has been shown to kill cancer cells in test tubes. Studies are underway to see if it has the same effect in humans. DO NOT take turmeric if you have gallstones or bile duct obstruction. Turmeric may interact with medications that slow blood clotting (anticoagulant/antiplatelet drugs).
Acupuncture is not used as a treatment for cancer itself, however, research suggests it can help reduce cancer-related symptoms (particularly the nausea and vomiting that often accompanies chemotherapy). Studies show that acupuncture may help reduce pain and shortness of breath. Acupressure (pressing on rather than needling acupuncture points) may also help control breathlessness. People can learn this technique and use it to treat themselves.
Some acupuncturists prefer to work with a person only after conventional medical cancer therapy. Others will provide acupuncture or herbal therapy during active chemotherapy or radiation. Make sure you discuss these treatments with your medical team before proceeding. Acupuncturists treat people with cancer based on an individualized assessment of the excesses and deficiencies of qi located in various meridians. In many cases of cancer-related symptoms, a qi deficiency is usually detected in the spleen or kidney meridians.
Mind Body Medicine
Relaxation techniques can help people undergoing surgery. One study found that people who received standard care plus use of guided imagery audiotapes before, during, and after surgery experienced significantly better sleep and less pain following the surgery than people who received only standard care.
Colorectal cancer may be hard to detect in pregnant women. That is because symptoms of the disease, such as rectal bleeding, nausea, and vomiting, resemble the symptoms of pregnancy. Pregnant women should avoid chemotherapy and radiation therapy. Surgery puts the fetus at risk. Usually folic acid and nutritional needs are maintained during pregnancy, and treatment is postponed until after the baby is delivered.
Prognosis and Complications
Follow up care after treatment for colorectal cancer is very important. If the cancer returns or if new cancer develops, it should be treated as soon as possible. Left untreated, colorectal cancer can spread to the liver or lungs, or a tumor may block the colon. People who have a colostomy may need counseling on how to care for the stoma, as well as how to deal with any emotional difficulties.
The prognosis depends on how deeply the tumor has grown into the tissue and whether the cancer has spread to lymph nodes in the abdominal region, or to other areas of the body.
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