Colon Polyps & Cancer
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Colon cancer is the leading cause of cancer-related deaths among nonsmokers. Colon cancer is the third leading cause of cancer death in men as well as women, and second among men and women combined. Colon cancer is also one of the most curable and preventable forms of cancer. This year we can expect greater than 140,000 new cases and 55,000 deaths from colon cancer.
You can dramatically reduce your risk of getting colon cancer by having regular colonoscopy examinations before symptoms develop. Colon cancer screening is so important, because when detected early, more than 90 percent of colon cancer patients can be cured.
The colon, also known as the large intestine, is the end section of the gastrointestinal tract. It is 3 to 5 feet in length and looks like a hollow pipe, with a ribbed inner surface. The colon is packed and folded into our abdominal cavity with amazing efficiency.
The colon is essential to our overall health and well-being. The colon maintains hydration by absorbing water that is vital to life (every cell in our body is dependent upon water for optimal functioning; our body is 60-75% water by weight). The colon also absorbs vitamin K, important for blood clotting and metabolism; vitamins B1 and B12, which together aid in blood cell formation and support organ systems including the heart, the brain and nervous system; and vitamin B2, important for maintaining skin health. Last but far from least, the colon prepares fecal matter for elimination and regulates the bowel movement process. After absorbing the nutrients we need, the colon rids the body of items we don’t need or can’t digest. The colon also makes our lives far easier by preparing and storing fecal matter until we find a convenient time to go to the bathroom.
Colon cancer is a malignant growth that occurs on the inner surface of the colon or rectum. Colon cancer usually begins many years earlier as a small noncancerous growth called a polyp. Polyps arise from genetic mutations in the DNA of the cells that line the colon. Over time, some polyps will grow larger until they develop into colon cancer. Although there are always exceptions, current data suggests that this malignant transformation is slow and may take 10 years or longer.
Colon cancer affects both women and men equally. Colon cancer is the number three leading cause of cancer-related deaths among women, behind lung and breast cancers. Women tend to form more polyps in the upper or more proximal part of the colon compared to men underscoring the importance of achieving an excellent colon prep and doing a full colonoscopy. The upper or more proximal part of the colon is not examined during a sigmoidoscopy.
A colon polyp is an abnormal tissue growth that arises on the inner surface of the colon. Polyps are caused by genetic mutations in the DNA of the cells that line the colon. Individuals can grow single or multiple polyps. What causes these mutations is not clearly understood, but genetics as well as diet likely play a role. Most colon polyps are non-cancerous and are almost always silent or asymptomatic (produce no symptoms). However, a large percentage of polyps have the capacity to continue to grow and evolve into a colon cancer and are, therefore, referred to as pre-cancerous polyps. It is felt that almost all colon cancers begin as polyps. At the polyp stage, we cannot tell which polyps are actively cancerous or are pre-cancerous. Only by removing the polyp at the time of colonoscopy can we then analyze the polyp microscopically to determine if the polyp is cancerous, pre-cancerous, or truly benign.
Over 75% of colon cancer cases are sporadic which means that they are not associated with ANY risk factors. Colon cancer is an equal opportunity disease – men and women are equally affected. The causes leading to polyp and cancer formation are not well understood, but a number of risk factors have been identified. These include:
The most common symptom of colon polyps and colon cancer is no symptom at all. The colon is a large capacity organ that can accommodate stool and tissue growths without your being aware. Stool can accumulate in your colon without your awareness until your body decides to eliminate the feces by signaling a bowel movement. When polyps become large or cancer develops, symptoms can include rectal bleeding, a change in bowel habits, narrow caliber stools, abdominal pain, or weakness and fatigue due to anemia related to slow blood loss.
Colon polyps are important to identify and remove, since the polyps may turn into colon cancer over time. While not every colon polyp turns to cancer, it is felt that almost every colon cancer begins as a small non-cancerous polyp. During a colonoscopy these polyps can be identified and removed, thus preventing the development of colon cancer. When a polyp is removed, it is sent to the pathology laboratory to be analyzed to determine the exact type of polyp.
Colorectal cancer is most often diagnosed by colonoscopy. Considered the gold standard of tests, this vital screening tool enables doctors to identify colon polyps before they become cancerous. In this routine exam, a long, flexible lighted tube (colonoscope) is inserted into the anus, through the rectum and into the colon. The scope inflates the large intestine with air or carbon dioxide gas, which enables the doctor to view the colon lining. A small camera mounted on the scope transmits a video image from inside the large intestine to a computer screen, allowing the doctor to carefully examine the intestinal lining.
Alternative tests to colonoscopy include virtual colonoscopy and a barium enema. These tests lack the accuracy of colonoscopy and do not afford the ability to biopsy tissue or remove polyps.
Surgery is the main treatment for colorectal cancer. Surgery for colorectal cancer most commonly involves a procedure called a colectomy, in which all or part of the colon is removed. Removal of the entire colon and the rectum is called a proctocolectomy; and removal of part of the colon but not the rectum is called a subtotal colectomy. Surgery may be performed laparoscopically or with open surgery, and generally requires a 4-7 day hospital stay. Chemotherapy drug treatment is recommended for more advanced stages of colorectal cancer. Radiation therapy, in which high-energy radiation is used to shrink tumors and kill cancer cells, is usually recommended to treat rectal cancer. Chemotherapy and radiation therapy may extend over several months.
With board certified doctors, the highest level of care and total patient comfort, patients choose the Center for Colonoscopy Excellence from throughout Northern California’s Bay Area, including Marin County, Oakland, Berkeley, Palo Alto and other local communities.
The Center for Colonoscopy Excellence, a division of San Francisco Gastroenterology, is the first in the Bay Area to comprehensively focus on screening colonoscopy. Our doctors have performed over 20,000 endoscopic procedures, placing them among the most experienced gastroenterologists in Northern California.
Over 90% of colon cancer deaths are preventable and screening is the key!
Make your health a priority and schedule an colonoscopy today »