Colon and Rectal Cancer
Colon cancer is among the most common types of cancer, while cancer of the rectum is diagnosed less frequently. The colon and rectum are part of the digestive system. Together, they form a long muscular tube known as the large intestine or bowel. The upper 5-6 feet of the large intestine is the colon, and the lower 5-6 inches is the rectum. Cancer occurs when cells of the colon or rectum become abnormal and grow uncontrollably interfering with the function of these organs and sometimes surrounding tissue and organs. When detected early, both colon and rectal cancer have high cure rates.
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Risk Factors
A personal or family history of colon and/or rectum cancer or polyps and inflammatory bowel disease have been associated with an increased risk for this type of cancer. Other risk factors include physical inactivity, high-fat and/or low-fiber diet, and an inadequate intake of fruits and vegetables.
Polyps are non-cancerous growths that can occur anywhere in the colon or rectum. Though they are not cancer, polyps should be removed because they can become cancerous. Individuals who have had a colon or rectal polyp are likely to develop more and should be examined regularly by a doctor.
Approximately 10 percent of colon cancers occur as a result of inherited genetic syndromes . The most common of these are Familial Colon Cancer (FCC) , Hereditary Non-Polyposis Colon Cancer (HNPCC) and Familial Adenomatous Polyposis (FAP) . Individuals with a family history of these diseases are at increased risk for developing colon cancer and should be followed closely by a physician. In recent years, Hopkins researchers have identified genetic mutations related to these inherited syndromes . Affected families can now benefit from genetic testing. More information and a registry for patients is available from the Hereditary Colon Cancer Program.
Diagnostic Tests
Several types of laboratory and clinical tests and examinations are used to diagnose colon and rectal cancer. Most
are relatively simple and painless, though some patients do experience minor discomfort requiring mild anesthetics. The tests include:
- Digital rectal examination - The doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas or masses.
- Fecal occult or hemoccult blood test - A small amount of stool is placed on a plastic slide or special paper and examined under a microscope for minute traces of blood.
- Sigmoidoscopy - The doctor uses a thin lighted tube called a sigmoidscope to look inside the rectum and lower colon for polyps, tumors or other abnormalities.
- Colonoscopy - A long instrument, similar to the sigmoidscope, is used to examine the inside of the entire colon for tumors and abnormal tissue. This procedure allows the doctor to see much further into the bowel than the sigmoidscope.
- Lower GI Series - This test is used to obtain an x-ray of the colon and rectum. It is sometimes called a barium enema because of the white, chalky substance given to patients prior to the x-ray. The barium outlines the colon and rectum on the x-rays to help the doctor see tumors or other abnormal tissue. The doctor may also expand the colon by gently pumping air during the test to look for small tumors.
If a polyp or tumor is found during colonoscopy or sigmoidoscopy, the doctor may remove all or part of it through the scope so that it can be examined under a microscope for the presence of cancer cells. This procedure is called a biopsy
Because colon and rectal cancer risk increases as we age and is easily detected through sigmoidoscopy and/or colonoscopy, cancer experts recommend the tests be done every three to five years after age 50, and earlier and more frequently for those people with a strong family history of the disease.
Cancer Symptoms
Colon and rectal cancer can cause a variety of symptoms. Early warning signs include:
- Bright red blood in the stool
- Diarrhea that is not the result of cold or flu
- A long period of constipation
- Crampy pain in the abdominal region
- Persistent decrease in size or caliber of stool
- Frequent feeling of distention or bloating in the abdominal or bowel region
- Weight loss
- Unusual and continuing lack of energy
Current Treatments
Treatment for colon and rectal cancers depend on the size and location of the tumor as well as other factors. A team of Johns Hopkins experts evaluate each patient to develop an individualized treatment plan based on the specific characteristics of the tumor. These doctors may order x-rays, ultrasound, a CT scan, and blood tests to determine the extent of the disease. This evaluation is an important step in helping the medical team design the best and most effective treatment regimen. Treatment plans may include a single therapy or combination of therapies including surgery, chemotherapy and radiation therapy.
Colon Cancer: When colon cancer is detected in an early stage, it is most commonly treated with a surgical procedure called a colectomy. The surgeon removes the part of the colon that contains the cancer as well as a small portion of surrounding normal tissue. In all but the rarest cases, the surgeon is able to reconnect the healthy sections of the colon and rectum, and bowel function soon returns to normal. If the cancer is completely removed during surgery, and pathologists determine that it was an early stage cancer, no further treatment is needed.
If surrounding tissue is found to contain any cancer cells, the doctors will likely recommend adjuvant chemotherapy. treatment with anticancer drugs. The drugs are given intravenously and/or orally and travel through the bloodstream to destroy tumor cells that may have broken away from original tumor and could begin to grow again elsewhere in the body. Sometimes chemotherapy is given prior to surgery to shrink a tumor and reduce the extent of surgery. This is called neo-adjuvant therapy. Chemotherapy is also given when the cancer has spread beyond the scope of surgery.
Rectal Cancer: Surgeons at Johns Hopkins have refined surgical techniques for rectal cancer that often allow nerves and sphincter muscles to remain intact, preserving continence and sexual function, and many times eliminating the need for external waste collection pouches known as ostomies. These innovative procedures have not only saved lives but greatly enhanced the quality of life for rectal cancer patients.
Some rectal cancer patients receive radiation therapy to the pelvis and/or chemotherapy following surgery to prevent the cancer from coming back or from spreading to other surrounding tissue and organs. Chemotherapy and radiation therapy is sometimes recommended prior to surgery to decrease the size of the tumor and further decrease the need for colostomy. Hopkins doctors now use transrectal ultrasound, which allows them to evaluate the size and depth of the tumor without surgery, making it possible to determine which patients would benefit from pre-surgical treatment.
Some patients, particularly those whose tumor is very low in the rectum, may require a colostomy. A colostomy is performed when the rectal cancer invades too close to the anal sphincter muscles requiring removal of the anus. To allow solid waste to leave the body, the surgeon creates an opening in the abdomen, called a stoma. The waste is collected in a special bag that covers the stoma. After a brief adjustment, most patients return to their normal lifestyle. To help with this transition, nurses and experts known as enterostomal therapists work closely with patients to teach them how to care for their colostomy and guide and support them in returning quickly to their normal activities.
Advanced Colon and Rectal Cancer: Experts at Johns Hopkins continue to refine standard therapies and develop new ones to offer viable treatment options for all colon and rectum cancer patients. In patients with advanced colon and rectum cancer, the disease frequently has spread beyond the colon and rectum to the liver. If there are a small number of tumors in the liver, the doctor can often remove them surgically. Recent advances at Johns Hopkins in surgical techniques, anesthesia support, and intraoperative ultrasonography have significantly improved outcomes for patients undergoing liver surgery. If surgical removal is not an option, doctors may use a technique known as cryotherapy. During this surgery, a probe containing liquid nitrogen is placed on the tumors to destroy them by freezing.
Johns Hopkins researchers are studying a number of drugs with known or potential activity in the treatment of colon and rectum cancer. The researchers also participate in large national studies of new treatment approaches. These innovative therapies are available to patients who cannot be treated with surgery. For some patients, outpatient treatment with an infusion pump to provide a continuous intravenous flow of anticancer drugs is an option. Others may benefit from a chemotherapy pump surgically implanted at the tumor site to deliver anticancer drugs directly to the tumor.
New Treatment Approaches
The collaborative efforts of the clinicians and researchers at Johns Hopkins Kimmel Cancer Center have led to many advances in the early detection and treatment of colon and rectal cancer. These endeavors promise to translate into better treatment outcomes for all patients.
Kimmel Cancer Center researchers were the first to isolate a series of mistakes in human DNA, called genetic mutations, that lead to the development and progression of colon and rectum cancer. These findings have already been used to develop screening blood tests for people with a family history of certain types of hereditary colon and rectum cancers. Subsequent work has led to the development of stool tests for non-hereditary olon cancer. Our scientists also were the first to decode the colon cancer genome. Several new anticancer agents are being studied for their ability to interfere with the genetic alterations and stop the initiation of cancer. As genetic causes continue to be uncovered, Hopkins researchers expect to improve broad-based screening tests to detect colon and rectum cancer in its earliest and most treatable stages.
