Polyps and cancer
Polyps are abnormal tissue growths that attach to the mucous membranes of various organs, most commonly the colon and rectum. Although polyps themselves are not cancerous, they can develop into colorectal cancer, which is a significant health concern. Risk factors for developing polyps and colorectal cancer include age over fifty, genetic predispositions, personal or family history of cancer, and lifestyle factors such as diet, smoking, and lack of exercise. While most polyps do not produce symptoms, larger ones may lead to issues like rectal bleeding or changes in bowel habits, often leading to their discovery during routine screenings.
Screening methods for colorectal cancer include fecal occult blood tests and endoscopic procedures like flexible sigmoidoscopy and colonoscopy. If a polyp is found, doctors typically remove it for testing; if cancerous, treatment options include surgery, radiation, chemotherapy, and targeted therapies. The prognosis is generally favorable when colorectal cancer is detected early, with approximately 90% of patients surviving at least five years post-diagnosis if treated promptly. Preventive measures are not definitively established, but maintaining a healthy lifestyle may reduce the risk of polyp formation and subsequent cancer development.
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Polyps and cancer
Also known as: Intestinal polyps, colorectal polyps, gastric polyps, nasal polyps, uterine polyps
Related conditions: Polyps may be related to certain genetic disorders that promote their growth in the colon, stomach, and rectum. Although not cancers themselves, these disorders make the person who inherits the defective gene more susceptible to cancer.
Definition: A polyp is an abnormal mass of tissue that attaches to mucous membranes, tissue linings that protect and keep moist the hollow organs of the body such as the colon, stomach, nose, sinuses, and uterus. Polyps can form on mucous membranes anywhere in the body but most commonly develop in the colon or rectum, both parts of the large intestine. They usually cause no problem, but some turn into colon or rectal cancer, generally called colorectal cancer because the two cancers have so much in common.
Risk factors: Risk factors for colorectal polyps include being past the age of fifty; inheriting a gene that causes polyp growth; previous colorectal, breast, ovarian, or uterine cancer; a personal or family history of polyps; radiation treatments to the stomach or pelvis; eating a diet high in fat and low in calcium and fiber; smoking; excessive alcohol intake; lack of exercise; and obesity.
Etiology and the disease process: Like most cancers, polyps are the result of abnormal cell growth. However, not all polyps are cancerous. Mutations in genes that control cell growth cause polyps to develop. Sometimes they continue to grow and turn cancerous. In general, the larger the polyp, the more likely it is to become cancerous. Doctors consider all polyps, even benign ones, precancerous and remove them whatever their size.
Incidence: According to the National Cancer Institute's 2014 statistics, colorectal cancer is the third most common cancer (excluding skin cancers) in both men and women and the second leading cause of death from cancer in the United States. (Lung cancer is the leading cause of cancer-related death in both men and women.) From 2007 to 2011, 15.9 per 100,000 people died from colorectal cancer each year, according to the National Cancer Institute.
Anyone can get polyps and colorectal cancer, but some people are more susceptible than others. Whites and African Americans are more likely to get polyps and die from colorectal cancer than are Hispanics, Asian Americans, and Native Americans. Women and men under the age of fifty get polyps and die from colorectal cancer at about equal rates. Over the age of fifty, men are more vulnerable than women.
Symptoms: Most polyps generate no symptoms. They are usually found during routine screenings for colon cancer. Very large polyps, however, can cause bleeding from the rectum, bloody stool, and changes in bowel movement patterns.
Screening and diagnosis: The most common screenings for colorectal cancer are as follows:
- Fecal occult blood test: This test checks for blood in the stool.
- Flexible sigmoidoscopy: This test examines the bottom third of the large intestine (the rectum and descending colon). The doctor inserts into the rectum a thin, flexible tube with a small camera on the end that is connected to a video monitor. This enables the doctor to look for polyps in real time.
- Colonoscopy: The procedure for this test is the same as for the sigmoidoscopy, but in this test, the doctor searches the entire large intestine.
Treatment and therapy: When a polyp is discovered during screening, the doctor removes it and tests it for cancer. If the polyp is found to be cancerous, any of four main treatments for colorectal cancer begins.
- Surgery is the main treatment. Surgeons cut out the cancerous tumor and part of the area surrounding it to prevent its spreading.
- Radiation therapy uses high-energy rays to kill or shrink cancer cells. In some cases, radiation is used to shrink the tumor before surgery. Radiation is also used to ease symptoms such as pain and bleeding in late stages of cancer.
- Chemotherapy (cancer-fighting drugs) may be beneficial in the early stages of cancer. The drugs also help relieve symptoms in late stages. Because chemotherapy affects cells other than cancer cells, it sometimes causes serious side effects.
- Targeted therapies use manufactured proteins called monoclonal antibodies that attack only the part of the cancer cells that makes them different from normal cells. This treatment causes fewer side effects than other chemotherapies.
Prognosis, prevention, and outcomes: Outcomes for patients with colorectal cancer are good when the cancer is caught early. As of 2014, the National Cancer Institute estimates that about 90 percent of patients whose cancer is diagnosed and treated before it has spread live at least five years after diagnosis, based on data collected between 2004 and 2010.
Because doctors do not know the exact causes of polyps, prevention measures are inexact. Generally, however, doctors believe that polyps may be prevented by maintaining a diet low in fat and high in fiber and certain cruciferous vegetables such as broccoli and cauliflower, not smoking, avoiding alcohol, exercising and maintaining a healthful weight, and (when prescribed by a doctor) taking aspirin.
Bibliography
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