Colorectal cancer is the second most common cause of cancer death among men and women in the United States. The National Cancer Institute estimates that in 2012 there will be approximately 143,000 new cases of colorectal cancer and about 51,000 deaths from the disease. The average American has an approximately 6 percent chance of developing colorectal cancer within his or her lifetime.
Routine screening of symptom-free men and women will lead to a reduction in the number of colorectal cancer cases and the number of deaths from colorectal cancer. The removal of precancerous lesions (polyps) during colonoscopy, a screening method described below, has been shown to significantly reduce the chance of developing colorectal cancer. In these guidelines, we review current recommendations for colorectal screening in the average-risk individuals as well as for those who are at higher risk because of family history or pre-existing medical conditions.
Colorectal Cancer Risk Types
Individuals age 50 and older are defined as average risk if they have the following:
- No symptoms
- No history of colorectal cancer or adenomatous polyps (benign growths that arise from the lining of the colon or rectum)
- No history of inflammatory bowel disease (ulcerative colitis or Crohn’s colitis)
- No family history of colorectal cancer or adenomatous polyps
Individuals are defined as high risk if they have one of the following:
- A first-degree relative (parent or sibling) who had cancer or a premalignant lesion (known as an adenomatous polyp) in the colon before the age of 60.
- A family history of familial adenomatous polyposis (FAP). A rare form of hereditary colon cancer, familial adenomatous polyposis is a condition in which family members develop hundreds or thousands of polyps in the colon at a very early age. These individuals will almost always go on to develop colon cancer by age 40.
- A family history of hereditary nonpolyposis colorectal cancer (HNPCC), a syndrome caused by mutations in specific genes that accounts for approximately 5 percent of all colorectal cancer diagnoses.
- A long history (more than eight years) of inflammatory bowel disease (ulcerative colitis or Crohn’s colitis).
Colorectal Cancer Screening Tests
Fecal Occult Blood Test (FOBT)
The fecal occult blood test chemically checks stool for hidden, or occult, blood, which in certain cases may be a sign of colorectal cancer or a premalignant polyp. I f blood is found, a colonoscopy is often performed.
Flexible sigmoidoscopy is a procedure in which a doctor uses a small, flexible tube with a camera to examine the inside of the rectum and the lower part of the colon, known as the sigmoid colon. The procedure also allows the collection of tissue samples (known as a biopsy) for microscopic examination. I f a premalignant polyp is detected during sigmoidoscopy, the patient should have a colonoscopy to screen the remainder of the colon.
This examination allows the doctor to inspect the rectum and the entire colon, using a thin, flexible tube called a colonoscope to which a small camera is attached. I t is inserted into the rectum while the patient lies on his or her side. Patients usually receive a sedative to ensure their comfort. The examination allows the detection of cancers in the early stages, before they give signs or produce symptoms. Polyps or other growths that are found during these examinations are usually removed at the time and sent to a laboratory for examination. A 2012 collaborative study led by Memorial Sloan-Kettering researchers, the largest of its kind, showed that removing polyps by colonoscopy not only prevents colorectal cancer from developing, but also prevents deaths from the disease.
Computed Tomographic Colonography (CTC), or “Virtual Colonoscopy”
Computed tomographic colonography (CTC), known commonly as virtual colonoscopy, is a new technique that uses CT scans to create a 3-D image that can be used to evaluate the bowel. At this time, it is still a research tool and is not used as a standard screening test. This technique does not allow a biopsy to be performed or the removal of polyps. Therefore, when an abnormal finding is detected, the patient needs to undergo a colonoscopy.
Double-Contrast Barium Enema (DCBE)
Double-contrast barium enema (DCBE) is an x-ray procedure that uses a chalky liquid called barium as a contrast agent to visualize the interior of the colon and rectum. Studies have shown DCBE to be less sensitive than colonoscopy in detecting lesions and polyps. It is rarely used for screening.
Our Colorectal Cancer Screening Guidelines
Routine screening for colorectal cancer is recommended starting at age 50 for average-risk individuals with no symptoms. And our doctors recommend colonoscopy every ten years as the preferred colorectal cancer screening modality.
Individuals who are at increased risk for colorectal cancer due to a personal or family history of colorectal cancer or adenomatous polyps, or a personal history of long-standing inflammatory bowel disease, may be recommended to undergo screening/surveillance colonoscopy starting at an earlier age and/or at more frequent intervals. Individuals with multiple family members affected with colorectal cancer and/or a family member affected with early-age-onset colorectal cancer, i.e., before age 50, should discuss this issue with their physician as they may be at risk of an underlying hereditary cancer predisposition syndrome, and if so should be referred for a clinical genetics consultation for further evaluation and individualized screening recommendations.
Individuals with a history of a non-colorectal primary cancer or who have undergone prior cancer therapy may also be at increased risk for colorectal cancer and thus recommendations for shorter screening followup intervals (i.e., five to ten years) may be considered.
Screening Guidelines for Individuals with a Family History of Hereditary Colon Cancer Syndromes
Hereditary Cancer Risk – An Overview
Hereditary cancer is the development of cancer due to an inherited gene mutation that has been passed from a parent to a child upon conception. People who have inherited such a gene mutation have also inherited a risk to develop cancer in their lifetime that is higher than the cancer risk of someone in the general population.
Over the past decade, scientists have discovered specific genes that can contribute to the development of hereditary breast, ovarian, colorectal, and other less common cancers. Genetic testing is now available for some of these types of hereditary cancers.
If you have a family history of cancer, the Clinical Genetics Service at Memorial Sloan-Kettering can help you understand more about your risk for the disease. We offer genetic testing and counseling and can help you in making informed medical decisions.
Below you will find our screening recommendations for individuals with a family history of certain types of colon cancer. The goal of screening is to prevent cancer and/or to find the cancer at an early enough stage that it can be treated.
Familial Adenomatous Polyposis (FAP)
Familial adenomatous polyposis (FAP) is a rare form of hereditary colon cancer, a condition in which family members develop hundreds or thousands of polyps in the colon at a very early age. These individuals will almost always go on to develop colon cancer by age 40. Some people have a variant of the disorder called attenuated familial adenomatous polyposis (AFAP) in which polyp growth is delayed. The average age for the onset of colorectal cancer in these individuals is 55.
Mutations in the adenomatous polyposis coli (APC) gene cause both classic FAP and attenuated familial adenomatous polyposis. These mutations affect the ability of the cell to maintain normal growth and function. Cell overgrowth resulting from mutations in the APC gene leads to the colon polyps seen in familial adenomatous polyposis.
Our FAP Screening Guidelines
We recommend annual sigmoidoscopy beginning at age ten to 15 or earlier if symptoms develop. After a diagnosis of adenomas or positive APC mutation, we recommend annual colonoscopy until prophylactic colectomy (the surgical removal of all or part of the colon) is performed in the late teen years. If no polyps are detected at the initial screening, the frequency of sigmoidoscopy can be reduced to every two years after age 24, every three years after age 34, and every three to five years after age 44. A full colonoscopy should also be considered in this group every ten years, starting at age 20. These recommendations are taken from the current NCCN guidelines.
It should be noted that the initial sigmoidoscopy recommendations apply only to those with mutation-proven FAP, whereas the spacing out of screening described above applies to those individuals without documented mutations but who are at familial risk.
We recommend that in individuals with clinically evident FAP, prophylactic colectomy be performed in the teen years or early 20s or earlier if dense polyposis or severe dysplasia is present. Following surgery, routine surveillance of whatever portion of the colon remains should continue, unless the entire colon has been removed.
Individuals with FAP or AFAP may develop polyps in other parts of the gastrointestinal (GI) tract. We now recommend upper GI screening every one to three years after the diagnosis of upper gastrointestinal adenomas. In the absence of adenomas, we recommend upper GI screening at least every four years beginning at age 25 to 30.
In addition, we recommend annual serum alpha feto-protein testing as well as (optionally) hepatic (liver) ultrasound in children with classic FAP from the time of their birth to five years of age in order to screen for hepatoblastoma (a rare liver cancer that occurs in infants and children). An annual ophthalmologic examination should done to look for freckle-like spots on the inside of the eye called congenital hypertrophy of the retinal pigment epithelium. We also recommend a comprehensive physical examination that includes palpation of the thyroid, and a focused physical exam of the skin and soft tissue as well as the eye examination.
For attenuated FAP, we recommend colonoscopy be performed in the late teen years, and as long as no polyps are detected, colonoscopies may be repeated every two to three years. However, when and if adenomatous polyps are detected, more frequent colonoscopies are recommended. We also recommend upper GI screening every four years beginning at age 25 to 30 and that surveillance of the skin, thyroid, and soft tissue and eye examinations continue on a regular basis even though these conditions are only rarely reported in the attenuated form of the syndrome.
Hereditary Nonpolyposis Colon Cancer
Hereditary nonpolyposis colon cancer (HNPCC), also known as Lynch syndrome, is a type of inherited cancer of the digestive tract, particularly the colon and rectum. People with Lynch syndrome also have an increased risk of cancers of the stomach, small intestine, liver, kidney, gallbladder ducts, upper urinary tract, brain, skin, and prostate.
Our HNPCC Screening Guidelines
For hereditary nonpolyposis colorectal cancer syndrome, we recommend annual colonoscopy beginning between ages 20 and 25 or five to ten years before the earliest diagnosis in the family, whichever comes first.
We recommend upper GI surveillance every four years beginning between ages 30 and 35.
Endometrial and ovarian cancer screening utilizing transvaginal ultrasound is recommended every six months beginning at age 30, and annual endometrial biopsies beginning at age 30. We also include in this a CA125 blood test every six months beginning at age 30. In addition, at Memorial Sloan-Kettering we consider removal of the ovaries and fallopian tubes for women who are HNPCC mutation carriers.
With respect to urinary tract screening, we recommend annual urine cytology beginning between ages 30 and 35. Urine cytology is a test to look for abnormal cells in your urine. Urine cytology is used, along with other tests, to diagnose urinary tract cancers. While there is no published evidence to suggest that this test is necessary, we have noted one case at our institution of a transitional cell cancer that was picked up by virtue of positive urine cytology. In those families in which urinary tract cancers are documented, at Memorial Sloan-Kettering we will sometimes also include renal (kidney) ultrasounds.
Not mentioned here are the HNPCC subset of syndromes that include Muir-Torre and Turcot syndromes. In these syndromes, we recommend skin screening as well as brain scans utilizing magnetic resonance imaging (MRI) on an individualized basis. In families with a history of pancreatic cancer, we will also recommend pancreatic screening (MRI and/or endoscopic ultrasound) – again, on an individualized basis.
Our Screening Guidelines for Other Familial Colon Cancers
If you have a first-degree relative who was diagnosed with an adenomatous polyp or colon cancer before the age of 60, we recommend colonoscopy at least every five years beginning at age 40 or ten years before the youngest age of diagnosis (either colon cancer or adenoma) in the family member, whichever occurs earlier.
If the first-degree relative had an adenomatous polyp or colon cancer diagnosed after age 60 or you have two second-degree relatives (such as an aunt, uncle, niece, nephew, or grandparent) who received either of these diagnoses, we recommend colonoscopy at least every ten years beginning at age 50.
Finally, we have defined another category that we refer to as “HNPCC like.” The screening recommendations for members of this category are individualized at the time of cancer risk counseling and generally follow the HNPCC recommendations.