Rectal Cancer | ASCRS
The rectum is the last 6 inches of the large intestine (colon). Rectal cancer arises from the lining of the rectum. In 2012, more than 40,000 people in the United States will be diagnosed with colorectal cancer, making it the third most common cancer in both men and women. About 5% of Americans will develop colorectal cancer during their lifetimes. Colorectal cancer is highly curable if detected in the early stages.
Diagram taken from existing ASCRS brochure "Polyps"
WHO IS AT RISK FOR RECTAL CANCER?
No one knows the exact causes of rectal cancer. Rectal cancer is more likely to occur as people get older, and more than 90% of people with this disease are diagnosed after age 50. Other risk factors include a family history of colorectal cancer (especially in close relatives), and a personal history of inflammatory bowel disease such as ulcerative colitis, colorectal polyps or cancers of other organs.
CAN RECTAL CANCER BE PREVENTED?
Rectal cancer is preventable. Nearly all rectal cancer develops from rectal polyps, which are benign growths on the rectal wall. Detection and removal of these polyps by colonoscopy reduces the risk of getting rectal cancer. Your doctor can provide exact recommendations for rectal cancer screening based on your medical and family history. Screening typically starts at age 50 in patients with average risk, or at younger ages in patients at higher risk for rectal cancer.
Though not definitely proven, there is some evidence that diet may play a significant role in preventing colorectal cancer. As far as we know, a diet high in fiber (whole grains, fruits, vegetables, nuts) and low in fat is the only dietary measure that might help prevent colorectal cancer
WHAT ARE THE SYMPTOMS OF RECTAL CANCER?
Many rectal cancers cause no symptoms at all and are detected during routine screening examinations. The most common symptoms of rectal cancer are a change in bowel habits, such as constipation or diarrhea, narrow shaped stools, or blood in your stool. You may also have pelvic or lower abdominal pain, unexplained weight loss, or feel tired all the time. Other common health problems can cause the same symptoms. Hemorrhoids do not cause rectal cancer but can produce similar symptoms. Anyone with these symptoms should see a doctor to be diagnosed and treated as early as possible. Abdominal pain and weight loss are typically late symptoms, indicating possible extensive disease.
WHAT TESTS ARE PERFORMED TO DIAGNOSE RECTAL CANCER?
- Physical exam and medical history
- Digital rectal exam (DRE)
- Proctoscopy: An office based exam of the rectum using a proctoscope, inserted into the rectum.
- Colonoscopy: A procedure to look inside the rectum and colon for polyps (small pieces of bulging tissue), abnormal areas, or cancer.
- Biopsy: The removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer.
WHAT DETERMINES THE PROGNOSIS (OUTCOME) FOR RECTAL CANCER?
- The stage of the cancer (how far advanced the cancer is).
- Where the cancer is found in the rectum.
- Whether the bowel is blocked or has a hole in it.
- Whether all of the tumor can be removed by surgery.
- The patient’s general health and ability to tolerate different treatment regimens.
- Whether the cancer has just been diagnosed or has recurred (come back).
HOW IS RECTAL CANCER STAGED?
- CT scan can accurately detect the presence of most cancer cells that have spread outside of the rectum.
- PET scan
- CEA assay
- MRI is one of the tests used for local staging. This will help determine if the tumor has spread through the wall of the rectum and if it has invaded nearby structures.
- Endoscopic ultrasound (EUS): A procedure in which an endoscope or rigid probe is inserted into the body through the rectum.
HOW IS RECTAL CANCER TREATED?
For complete cure, surgery to remove the rectal cancer is almost always required. Depending on the location and stage, this may be performed through the anus (opening of the rectum) or through the abdomen. Rectal cancer surgery removes the cancer and lymph nodes, along with a small portion of normal rectum on either side of the tumor. Creation of a colostomy (opening the intestine to a bag on the skin) is typically needed only in a very small number of patients. Trained surgeons may use minimally invasive surgical techniques depending on certain features of your cancer. Your surgeon will discuss these features with you prior to the operation. Additional treatment with chemotherapy or radiation therapy may be offered either before or after the surgery, depending on the stage of the cancer.
WHAT FACTORS INFLUENCE PROGNOSIS (OUTCOME)?
The outcome of patients with rectal cancer is most clearly related to the stage at the time of diagnosis, with cancer that is confined to the lining of colon having the best chance of success. This is one reason why early detection through screening methods like colonoscopy is crucial.
WHAT FOLLOW-UP IS NEEDED AFTER TREATMENT?
After treatment for rectal cancer, a blood test to measure amounts of CEA (a substance in the blood that may be increased when cancer is present) may be done to see if the cancer has come back. Routine CT scans, clinical examinations, and colonoscopy are also performed at intervals determined by the stage.
WHAT IS A COLON AND RECTAL SURGEON?
Colon and rectal surgeons are experts in the surgical and non-surgical treatment of diseases of the colon, rectum and anus. They have completed advanced surgical training in the treatment of these diseases as well as full general surgical training. Board-certified colon and rectal surgeons complete residencies in general surgery and colon and rectal surgery, and pass intensive examinations conducted by the American Board of Surgery and the American Board of Colon and Rectal Surgery. They are well-versed in the treatment of both benign and malignant diseases of the colon, rectum and anus and are able to perform routine screening examinations and surgically treat conditions if indicated to do so.
The American Society of Colon and Rectal Surgeons is dedicated to ensuring high-quality patient care by advancing the science, prevention and management of disorders and diseases of the colon, rectum and anus. These brochures are inclusive but not prescriptive. Their purpose is to provide information on diseases and processes, rather than dictate a specific form of treatment. They are intended for the use of all practitioners, health care workers and patients who desire information about the management of the conditions addressed. It should be recognized that these brochures should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtain the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all the circumstances presented by the individual patient.