March is Colon and Rectal Cancer Screening Month.
March has been chosen to recognize the importance of screening for colon and rectal cancer. We have summarized the important information concerning screening for colon and rectal cancer and have listed several helpful websites to help answer your questions concerning colon and rectal cancer. (Click here for additional information concerning the importance of screening for colorectal cancer and choosing a colorectal surgeon.)
There are approximately 133,00 new cases of colorectal cancer per year in the United States and approximately 54,000 deaths per year. The lifetime probability of an individual developing colorectal cancer is 5-6%. Aggressive screening for colorectal cancer could decrease both the numbers of new cases and the numbers of deaths per year.
In 1994 a consortium of five medical societies (American College of Gastroenterology, American Society for Gastrointestinal Endoscopy, American Gastroenterological Association, American Society of Colon and Rectal Surgeons, and Society of American Gastrointestinal Endoscopic Surgeons) responded to a request from the Agency for Health Care Policy and Research to develop national guidelines for colorectal cancer screening. Over a 2-year period an interdisciplinary panel of health care professionals reviewed all the available literature concerning screening for colorectal cancer. The result of this comprehensive study was published in Gastroenterology in 1997 .
The American Cancer Society revised their guidelines for colorectal cancer screening based on the report of the consortium. The American Society of Colon and Rectal Surgeons, in turn, adopted the guidelines of the American Cancer Society. These guidelines separate individuals into low or average risk (65-75% of people), moderate or increased risk (20-30%), and high risk (6-8%) groups.
LOW RISK INDIVIDUALS are those that are asymptomatic, with no family history of colorectal cancer in a first-degree relative, and with no other risk factors. Screening should begin at age 50. Digital rectal exam and fecal occult blood testing (FOBT) should be performed annually. If the FOBT is negative, flexible sigmoidoscopy is performed every 5 years. If the FOBT is positive, examination of the entire colon by colonoscopy is carried out.
If at the time of flexible sigmoidoscopy, a polyp is identified, it should be biopsied. If the pathological diagnosis is a hyperplastic polyp, no further studies are necessary. If the diagnosis is an adenomatous polyp, then colonoscopy should be carried out.
Colonoscopy allows visual examination of the entire colon, detection and removal of most polyps, and biopsy of cancers. Colonoscopy can be recommended as screening of average risk individuals. The interval selected is every 10 years because there is only a slight risk of developing advanced adenomas during surveillance after an initial examination with negative results.
MODERATE RISK INDIVIDUALS are those with one or more first-degree relatives (sibling, parent, or child) with colorectal cancer and those with a personal history of adenomatous polyps or colorectal cancer.
CANCER IN A FAMILY MEMBER. If an individual has 2 or more close relatives or 1 close relative under the age of 55 with colorectal cancer, screening should begin at age 40 or 10 years before the age of the youngest affected family member. Screening should be colonoscopy.
If an individual has 1 close relative with colorectal cancer over the age of 55, the risk is not as great and screening should begin at age 50 or 10 years before the age of the affected family member.
POLYP (ADENOMA) SURVEILLANCE. Following colonoscopy, if a large polyp (>1 cm.) is removed or if multiple polyps are removed, colonoscopy is repeated in 1 year. If only a small polyp (<1cm.) is removed, colonoscopy is repeated in 3 years. Once a normal (negative) colonoscopy has been performed, colonoscopy is carried out every 5 years. The finding of an adenoma at any subsequent examination may prompt yearly colonoscopies until the colon is again clear of polyps.
CANCER SURVEILLANCE. When facing surgery for a malignant tumor, the patient should have colonoscopy prior to surgery. Colonoscopy should be repeated 1 year after surgery. If colonoscopy is not feasible prior to surgery, it should be carried out 3-6 months later. If the follow-up examination is normal, it is repeated in 3 years, and if still normal, then every 5 years.
(Patients with prior uterine, ovarian, or breast cancer and those with a history of pelvic radiation are at increased risk for colorectal cancer and should be offered colonoscopic examinations.)
HIGH RISK INDIVIDUALS include those with hereditary or genetic predisposition for the development of colorectal cancer and those patients with inflammatory bowl disease.
Patients with FAMILIAL ADENOMATOUS POLYPOSIS (FAP) develop hundreds of adenomatous polyps and eventually develop cancer if the colon is not removed. An affected parent transmits the disease to ½ of his offspring. If an individual has a family history of FAP, screening begins at puberty (12-14) and should be performed annually. Sigmoidoscopy is adequate screening for the development of these polyps in FAP. The duration of the screening is not clear, but is usually carried out to age 40. If a patient with FAP has had a subtotal colectomy, the rectum remains intact and that patient should have sigmoidoscopy every 6-12 months.
If a patient has a family history of HEREDITARY NONPOLYPOSIS COLORECTAL CANCER (HNPCC), colonoscopy begins at age 20 or 10 years prior to the age of the youngest family member with colorectal cancer. Colonoscopy is required for screening because cancers in this condition tend to occur in the right colon. Colonoscopy is performed every 2 years until age 40 and then yearly.
The availability of genetic testing may change the recommendations for screening of patients with a family history of FAP and HNPCC.
The presence of INFLAMMATORY BOWEL DISEASE, either chronic ulcerative colitis (CUC) or Crohn’s disease (CD) significantly increases the risk of colorectal cancer. In CUC, the risk of cancer increases with the duration of the disease and with the extent of the disease. When a patient has CUC involving the entire colon, screening (colonoscopy) should begin after 8 years of the disease and should be done every 1-2 years. When CUC is limited to the left colon, screening should begin after 15 years and should be done every 1-2 years.
In patients with long-standing Crohn’s disease, there is an increased risk of colorectal cancer, but not as high as in CUC. Screening should begin after 15 years and should be carried out every 1-2 years.
Simmang CL, Senatore P, Lowry A. et al. Practice Parameters for Detection of Colorectal Neoplasms. Diseases of the Colon & Rectum 1999; 42: 1123-1129.
These websites contain helpful information concerning colon and rectal cancer and screening recommendations.
www.gastro.org/public/cc_screening.html - Colon and rectal cancer screening guidelines from the American Gastroenterological Association.
www.fascrs.org - American Society of Colon and Rectal Surgeons - See Practice Parameters for colon and rectal cancer screening.
www.coloncancerprevention.org - a web-site created by Dr. Ernestine Hambrick devoted to preventing colorectal cancer through public awareness and screening.
www.LSACCA.org - a web site describing one person's battle with colon cancer which also has very good information concerning the signs, symptoms, diagnosis and prevention of colorectal cancer.