Rectal Cancer

Rectal cancer is a disease in which malignant (cancer) cells form in the tissues of the rectum.
The rectum is part of the body's digestive system. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The digestive system is made up of the esophagus, stomach, and the small and large intestines. The first 6 feet of the large intestine are called the large bowel or colon. The last 6 inches are the rectum and the anal canal. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).

Age and family history can affect the risk of developing rectal cancer.
The following are possible risk factors for rectal cancer:

• Age 50 years or older.
• A family history of cancer of the colon or rectum.
• A personal history of cancer of the colon, rectum, ovary, endometrium, or breast.
• A history of ulcerative colitis (ulcers in the lining of the large intestine) or Crohn's disease.
• Certain hereditary conditions, such as familial adenomatous polyposis and hereditary nonpolyposis colon cancer (HNPCC; Lynch syndrome).

Possible signs of rectal cancer include a change in bowel habits or blood in the stool.
These and other symptoms may be caused by rectal cancer or other conditions. A doctor should be consulted if any of the following problems occur:

• A change in bowel habits.
• Blood (either bright red or very dark) in the stool.
• Diarrhea, constipation, or feeling that the bowel does not empty completely.
• Stools that are narrower than usual.
• General abdominal discomfort (frequent gas pains, bloating, fullness, or cramps).
• Weight loss with no known reason.
• Constant tiredness.
• Vomiting.

Tests that examine the rectum and colon are used to detect (find) and diagnose rectal cancer.
Tests used in diagnosing rectal cancer include the following:

• Fecal occult blood test: A test to check stool (solid waste) for blood that can only be seen with a microscope. Small samples of stool are placed on special cards and returned to the doctor or laboratory for testing.
• Digital rectal exam: An exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the rectum to feel for lumps or abnormal areas.
• Barium enema: A series of x-rays of the lower gastrointestinal tract. A liquid that contains barium (a silver-white metallic compound) is put into the rectum. The barium coats the lower gastrointestinal tract and x-rays are taken. This procedure is also called a lower GI series.
• Sigmoidoscopy: A procedure to look inside the rectum and sigmoid (lower) colon for polyps, abnormal areas, or cancer. A sigmoidoscope (a thin, lighted tube) is inserted through the rectum into the sigmoid colon. Polyps or tissue samples may be taken for biopsy.
• Colonoscopy: A procedure to look inside the rectum and colon for polyps, abnormal areas, or cancer. A colonoscope (a thin, lighted tube) is inserted through the rectum into the colon. Polyps or tissue samples may be taken for biopsy.
• Biopsy: The removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer.

Certain factors affect treatment options and prognosis (chance of recovery).
The treatment options and prognosis (chance of recovery) depend on the stage of the cancer (whether it affects the inner lining of the rectum only, involves the whole rectum, or has spread to other places in the body), the type of cancer, the size of the tumor, and the patient's general health.

Stages of Rectal Cancer

After rectal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the rectum or to other parts of the body.
The process used to find out whether cancer has spread within the rectum or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan the best treatment. The following tests and procedures may be used in the staging process:

• Digital rectal exam: An exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the rectum to feel for lumps or abnormal areas.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• Sigmoidoscopy or colonoscopy and biopsy: A procedure to look inside the rectum and colon for polyps, abnormal areas, or cancer. A sigmoidoscope or colonoscope is inserted through the rectum into the colon. Polyps or tissue samples may be taken for biopsy.
• Endoscopic ultrasound (EUS): A procedure in which an endoscope (a thin, lighted tube) is inserted into the body. The endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography.

The following stages are used for rectal cancer:

Stage 0 (carcinoma in situ)
In stage 0, cancer is found in the innermost lining of the rectum only. Stage 0 cancer is also called carcinoma in situ.

Stage I
In stage I, cancer has spread beyond the innermost lining of the rectum to the second and third layers and involves the inside wall of the rectum, but it has not spread to the outer wall of the rectum or outside the rectum. Stage I rectal cancer is sometimes called Dukes' A rectal cancer.

Stage II
In stage II, cancer has spread outside the rectum to nearby tissue, but it has not gone into the lymph nodes (small, bean-shaped structures found throughout the body that filter substances in a fluid called lymph and help fight infection and disease). Stage II rectal cancer is sometimes called Dukes' B rectal cancer.

Stage III
In stage III, cancer has spread to nearby lymph nodes, but it has not spread to other parts of the body. Stage III rectal cancer is sometimes called Dukes' C rectal cancer.

Stage IV
In stage IV, cancer has spread to other parts of the body, such as the liver, lungs, or ovaries. Stage IV rectal cancer is sometimes called Dukes' D rectal cancer.

Recurrent Rectal Cancer
Recurrent rectal cancer is cancer that has recurred (come back) after it has been treated. The cancer may come back in the rectum or in other parts of the body, such as the colon, pelvis, liver, or lungs.

Treatment Option Overview

There are different types of treatment for patients with rectal cancer.
Different types of treatment are available for patients with rectal cancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. Before starting treatment, patients may want to think about taking part in a clinical trial. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment

Three types of standard treatment are used:

Surgery
Surgery is the most common treatment for all stages of rectal cancer. A doctor may remove the cancer using one of the following types of surgery:

• Local excision: If the cancer is found at a very early stage, the doctor may remove it without cutting into the abdomen. If the cancer is found in a polyp (a growth that protrudes from the rectal mucous membrane), the operation is called a polypectomy.
• Resection: If the cancer is larger, the doctor will perform a resection of the rectum (removing the cancer and a small amount of healthy tissue around it). The doctor will then perform an anastomosis (sewing the healthy parts of the rectum together, sewing the remaining rectum to the colon, or sewing the colon to the anus). The doctor will also take out lymph nodes near the rectum and examine them under a microscope to see if they contain cancer.
• Resection and colostomy: If the doctor is not able to sew the rectum back together, a stoma (an opening) is made on the outside of the body for waste to pass through. This procedure is called a colostomy. Sometimes the colostomy is needed only until the rectum has healed, and then it can be reversed. If the doctor needs to remove the entire rectum, however, the colostomy may be permanent.

Even if the doctor removes all the cancer that can be seen at the time of the operation, some patients may be offered chemotherapy or radiation therapy after surgery to kill any cancer cells that are left. Treatment given after surgery to increase the chances of a cure is called adjuvant therapy.

Radiation therapy
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.

Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly in the spinal column, a body cavity such as the abdomen, or an organ, the drugs mainly affect cancer cells in those areas. The way the chemotherapy is given depends on the type and stage of the cancer being treated.

After treatment, a blood test to measure amounts of carcinoembryonic antigen (a substance in the blood that may be increased when cancer is present) may be done to see if the cancer has come back.

Other types of treatment are being tested in clinical trials.

Chemotherapy and biologic therapy
Biologic therapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy.

Treatment Options by Stage

Stage 0 Rectal Cancer
Treatment of stage 0 (carcinoma in situ) rectal cancer may include the following:

• Local excision (surgery to remove the tumor without cutting into the abdomen) or simple polypectomy (surgery to remove a growth that protrudes from the rectal mucous membrane).
• Resection (surgery to remove the cancer). This is done when the cancerous tissue is too large to remove by local excision.
• Internal or external radiation therapy.

Stage I Rectal Cancer
Treatment of stage I rectal cancer may include the following:

• Surgery to remove the tumor with or without anastomosis (joining the cut ends of the rectum).
• Surgery to remove the tumor with or without radiation therapy and chemotherapy.
• Internal and/or external radiation therapy.

Stage II Rectal Cancer
Treatment of stage II rectal cancer may include the following:

• Resection with or without anastomosis (joining the cut ends of the rectum and colon, or the colon and anus) followed by chemotherapy and radiation therapy.
• Partial or total pelvic exenteration (surgery to remove the organs and nearby structures of the pelvis), depending on where the cancer has spread. Surgery is followed by radiation therapy and chemotherapy.
• Radiation therapy with or without chemotherapy followed by surgery and chemotherapy.
• Radiation therapy during surgery followed by external-beam radiation therapy and chemotherapy.
• A clinical trial evaluating new treatment options.

Stage III Rectal Cancer
Treatment of stage III rectal cancer may include the following:

• Resection with or without anastomosis (joining the cut ends of the rectum and colon, or the colon and anus) followed by chemotherapy and radiation therapy.
• Partial or total pelvic exenteration (surgery to remove the organs and nearby structures of the pelvis), depending on where the cancer has spread. Surgery is followed by radiation therapy and chemotherapy.
• Radiation therapy with or without chemotherapy followed by surgery and chemotherapy.
• Radiation therapy during surgery followed by external-beam radiation therapy and chemotherapy.
• Chemotherapy and radiation therapy to relieve symptoms caused by advanced cancer.
• A clinical trial evaluating new treatment options.

Stage IV Rectal Cancer
Treatment of stage IV rectal cancer may include the following:

• Resection/anastomosis (surgery to remove the cancer and join the cut ends of the rectum and colon, or colon and anus) to relieve symptoms caused by advanced cancer.
• Surgery to remove parts of other organs, such as the liver, lung, and ovaries, where the cancer may have spread.
• Chemotherapy and radiation therapy to relieve symptoms caused by advanced cancer.
• Chemotherapy following surgery.
• Clinical trials of chemotherapy and biological therapy.

Treatment Options for Recurrent Rectal Cancer
Treatment of recurrent rectal cancer may include the following:

• Surgery to remove the tumor or as palliative therapy to relieve symptoms caused by advanced cancer.
• Surgery to remove parts of other organs, such as the liver, lungs, and ovaries, where the cancer may have spread.
• Radiation therapy and/or chemotherapy as palliative therapy to reduce the size of the tumor and relieve symptoms caused by advanced cancer.

Clinical trials are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Cancer.gov Web site. Choosing the most appropriate cancer treatment is a decision that ideally involves the patient, family, and health care team.

Source: National Institutes of Health; National Cancer Institute