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Rectal Cancer Treatment (PDQ®)

Patient Version
Last Modified: 11/10/2011

Stages of Rectal Cancer

Key Points for This Section


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 treatment. The following tests and procedures may be used in the staging process:

  • Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the abdomen, pelvis, or chest, 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).
  • Endoscopic ultrasound (EUS): A procedure in which an endoscope or rigid probe is inserted into the body through the rectum. The endoscope or probe has a light and a lens for viewing. A device at the end 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.
  • PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
  • Carcinoembryonic antigen (CEA) assay: A test that measures the level of CEA in the blood. CEA is released into the bloodstream from both cancer cells and normal cells. When found in higher than normal amounts, it can be a sign of rectal cancer or other conditions.

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

  • Through tissue. Cancer invades the surrounding normal tissue.
  • Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
  • Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for rectal cancer:

Stage 0 (Carcinoma in Situ)

In stage 0, abnormal cells are found in the mucosa (innermost layer) of the rectum wall. These abnormal cells may become cancer and spread. Stage 0 is also called carcinoma in situ.

Stage I

In stage I, cancer has formed in the mucosa (innermost layer) of the rectum wall and has spread to the submucosa (layer of tissue under the mucosa). Cancer may have spread to the muscle layer of the rectum wall.

Stage II

Stage II rectal cancer is divided into stage IIA, stage IIB, and stage IIC.

  • Stage IIA: Cancer has spread through the muscle layer of the rectum wall to the serosa (outermost layer) of the rectum wall.
  • Stage IIB: Cancer has spread through the serosa (outermost layer) of the rectum wall but has not spread to nearby organs.
  • Stage IIC: Cancer has spread through the serosa (outermost layer) of the rectum wall to nearby organs.

Stage III

Stage III rectal cancer is divided into stage IIIA, stage IIIB, and stage IIIC.

In stage IIIA:

  • Cancer may have spread through the mucosa (innermost layer) of the rectum wall to the submucosa (layer of tissue under the mucosa) and may have spread to the muscle layer of the rectum wall. Cancer has spread to at least one but not more than 3 nearby lymph nodes or cancer cells have formed in tissues near the lymph nodes; or
  • Cancer has spread through the mucosa (innermost layer) of the rectum wall to the submucosa (layer of tissue under the mucosa). Cancer has spread to at least 4 but not more than 6 nearby lymph nodes.

In stage IIIB:

  • Cancer has spread through the muscle layer of the rectum wall to the serosa (outermost layer) of the rectum wall or has spread through the serosa but not to nearby organs. Cancer has spread to at least one but not more than 3 nearby lymph nodes or cancer cells have formed in tissues near the lymph nodes; or
  • Cancer has spread to the muscle layer of the rectum wall or to the serosa (outermost layer) of the rectum wall. Cancer has spread to at least 4 but not more than 6 nearby lymph nodes; or
  • Cancer has spread through the mucosa (innermost layer) of the rectum wall to the submucosa (layer of tissue under the mucosa) and may have spread to the muscle layer of the rectum wall. Cancer has spread to 7 or more nearby lymph nodes.

In stage IIIC:

  • Cancer has spread through the serosa (outermost layer) of the rectum wall but has not spread to nearby organs. Cancer has spread to at least 4 but not more than 6 nearby lymph nodes; or
  • Cancer has spread through the muscle layer of the rectum wall to the serosa (outermost layer) of the rectum wall or has spread through the serosa but has not spread to nearby organs. Cancer has spread to 7 or more nearby lymph nodes; or
  • Cancer has spread through the serosa (outermost layer) of the rectum wall and has spread to nearby organs. Cancer has spread to one or more nearby lymph nodes or cancer cells have formed in tissues near the lymph nodes.

Stage IV

Stage IV rectal cancer is divided into stage IVA and stage IVB.

  • Stage IVA: Cancer may have spread through the rectum wall and may have spread to nearby organs or lymph nodes. Cancer has spread to one organ that is not near the rectum, such as the liver, lung, or ovary, or to a distant lymph node.
  • Stage IVB: Cancer may have spread through the rectum wall and may have spread to nearby organs or lymph nodes. Cancer has spread to more than one organ that is not near the rectum or into the lining of the abdominal wall.


Glossary Terms

abdomen (AB-doh-men)
The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.
abdominal (ab-DAH-mih-nul)
Having to do with the abdomen, which is the part of the body between the chest and the hips that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.
abnormal (ab-NOR-mul)
Not normal. An abnormal lesion or growth may be cancer, premalignant (likely to become cancer), or benign (not cancer).
blood (blud)
A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.
bone cancer (bone KAN-ser)
Primary bone cancer is cancer that forms in cells of the bone. Some types of primary bone cancer are osteosarcoma, Ewing sarcoma, malignant fibrous histiocytoma, and chondrosarcoma. Secondary bone cancer is cancer that spreads to the bone from another part of the body (such as the prostate, breast, or lung).
breast cancer (brest KAN-ser)
Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.
cancer (KAN-ser)
A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.
capillary (KA-pih-layr-ee)
The smallest type of blood vessel. A capillary connects an arteriole (small artery) to a venule (small vein) to form a network of blood vessels in almost all parts of the body. The wall of a capillary is thin and leaky, and capillaries are involved in the exchange of fluids and gases between tissues and the blood.
carcinoma in situ (KAR-sih-NOH-muh in SY-too)
A group of abnormal cells that remain in the place where they first formed. They have not spread. These abnormal cells may become cancer and spread into nearby normal tissue. Also called stage 0 disease.
CEA
A substance that may be found in the blood of people who have colon cancer, other types of cancer or diseases, or who smoke tobacco. CEA levels may help keep track of how well cancer treatments are working or if cancer has come back. It is a type of tumor marker. Also called carcinoembryonic antigen.
CEA assay (... A-say)
A laboratory test that measures the level of carcinoembryonic antigen (CEA) in the blood. An increased amount of CEA may be found in the blood of people who have colon cancer or other types of cancer, certain other diseases, or who smoke. The amount of CEA in the blood may also help keep track of how well cancer treatments are working or if cancer has come back. CEA is a type of tumor marker. Also called carcinoembryonic antigen assay.
cell (sel)
The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.
chest x-ray (chest EX-ray)
An x-ray of the structures inside the chest. An x-ray is a type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease.
contrast material (KON-trast muh-TEER-ee-ul)
A dye or other substance that helps show abnormal areas inside the body. It is given by injection into a vein, by enema, or by mouth. Contrast material may be used with x-rays, CT scans, MRI, or other imaging tests.
CT scan (… skan)
A series of detailed pictures of areas inside the body taken from different angles. The pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography scan, computerized axial tomography scan, and computerized tomography.
endoscope (EN-doh-SKOPE)
A thin, tube-like instrument used to look at tissues inside the body. An endoscope has a light and a lens for viewing and may have a tool to remove tissue.
endoscopic ultrasound (en-doh-SKAH-pik...)
A procedure in which an endoscope is inserted into the body. An endoscope is a thin, tube-like instrument that has a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal organs to make a picture (sonogram). Also called endosonography and EUS.
glucose (GLOO-kose)
A type of sugar; the chief source of energy for living organisms.
injection (in-JEK-shun)
Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."
invasive cancer (in-VAY-siv KAN-ser)
Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.
liver (LIH-ver)
A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.
lung (lung)
One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.
lymph (limf)
The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.
lymph node (limf node)
A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.
lymph vessel (limf ...)
A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.
lymphatic system (lim-FA-tik SIS-tem)
The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.
malignant (muh-LIG-nunt)
Cancerous. Malignant cells can invade and destroy nearby tissue and spread to other parts of the body.
metastasis (meh-TAS-tuh-sis)
The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).
MRI
A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, NMRI, and nuclear magnetic resonance imaging.
mucosa (myoo-KOH-suh)
The moist, inner lining of some organs and body cavities (such as the nose, mouth, lungs, and stomach). Glands in the mucosa make mucus (a thick, slippery fluid). Also called mucous membrane.
organ (OR-gun)
A part of the body that performs a specific function. For example, the heart is an organ.
ovary (OH-vuh-ree)
One of a pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus.
pelvis (PEL-vus)
The lower part of the abdomen, located between the hip bones.
PET scan (… skan)
A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called positron emission tomography scan.
primary tumor (PRY-mayr-ee TOO-mer)
The original tumor.
radioactive (RAY-dee-oh-AK-tiv)
Giving off radiation.
rectal cancer (REK-tul KAN-ser)
Cancer that forms in the tissues of the rectum (the last several inches of the large intestine closest to the anus).
rectum (REK-tum)
The last several inches of the large intestine closest to the anus.
scanner (SKA-ner)
In medicine, an instrument that takes pictures of the inside of the body.
serosa (seh-ROH-suh)
The outer lining of organs and body cavities of the abdomen and chest, including the stomach. Also called serous membrane.
sonogram (SAH-noh-gram)
A computer picture of areas inside the body created by bouncing high-energy sound waves (ultrasound) off internal tissues or organs. Also called ultrasonogram.
stage (stayj)
The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.
stage 0 colorectal carcinoma in situ (...KOH-loh-REK-tul KAR-sih-NOH-muh in SY-too)
Abnormal cells are found in the mucosa (innermost layer) of the colon and/or rectal wall. These abnormal cells may become cancer.
stage I colorectal cancer (...KOH-loh-REK-tul KAN-ser)
Cancer has spread from the mucosa (innermost layer) of the colon and/or rectal wall to the submucosa (layer of tissue under the mucosa) of the colon and/or rectal wall. Cancer may have spread to the muscle layer of the colon and/or rectal wall. Also called Dukes A colorectal cancer.
stage II colorectal cancer (...KOH-loh-REK-tul KAN-ser)
Stage II colorectal cancer is divided into stage IIA, stage IIB, and stage IIC. In stage IIA, cancer has spread through the muscle layer of the colon and/or rectal wall to the serosa (outermost layer) of the colon and/or rectal wall. In stage IIB, cancer has spread through the serosa of the colon and/or rectal wall but has not spread to nearby organs. In stage IIC, cancer has spread through the serosa of the colon and/or rectal wall to nearby organs. Also called Dukes B colorectal cancer.
stage III colorectal cancer (...KOH-loh-REK-tul KAN-ser)
Stage III colorectal cancer is divided into stage IIIA, stage IIIB, and stage IIIC. In stage IIIA, (1) cancer may have spread through the mucosa (innermost layer) of the colon and/or rectal wall to the submucosa (layer of tissue under the mucosa) and may have spread to the muscle layer of the colon and/or rectal wall. Cancer has spread to at least one but not more than 3 nearby lymph nodes, or cancer cells have formed in tissues near the lymph nodes; or (2) cancer has spread through the mucosa of the colon and/or rectal wall to the submucosa. Cancer has spread to at least 4 but not more than 6 nearby lymph nodes. In stage IIIB, (1) cancer has spread through the muscle layer of the colon and/or rectal wall to the serosa (outermost layer) of the colon and/or rectal wall or has spread through the serosa but not to nearby organs. Cancer has spread to at least one but not more than 3 nearby lymph nodes, or cancer cells have formed in tissues near the lymph nodes; or (2) cancer has spread to the muscle layer of the colon and/or rectal wall or to the serosa of the colon and/or rectal wall. Cancer has spread to at least 4 but not more than 6 nearby lymph nodes; or (3) cancer has spread through the mucosa of the colon and/or rectal wall to the submucosa and may have spread to the muscle layer of the colon and/or rectal wall. Cancer has spread to 7 or more nearby lymph nodes. In stage IIIC, (1) cancer has spread through the serosa of the colon and/or rectal wall but has not spread to nearby organs. Cancer has spread to at least 4 but not more than 6 nearby lymph nodes; or (2) cancer has spread through the muscle layer of the colon and/or rectal wall to the serosa of the colon and/or rectal wall or has spread through the serosa but has not spread to nearby organs. Cancer has spread to 7 or more nearby lymph nodes; or (3) cancer has spread through the serosa of the colon and/or rectal wall and has spread to nearby organs. Cancer has spread to one or more nearby lymph nodes, or cancer cells have formed in tissues near the lymph nodes. Also called Dukes C colorectal cancer.
stage IV colorectal cancer (...KOH-loh-REK-tul KAN-ser)
Stage IV colorectal cancer is divided into stage IVA and stage IVB. In stage IVA, cancer may have spread through the colon and/or rectal wall and may have spread to nearby organs or lymph nodes. Cancer has spread to one organ that is not near the colon and/or rectum, such as the liver, lung, or ovary, or to a distant lymph node. In stage IVB, cancer may have spread through the colon and/or rectal wall and may have spread to nearby organs or lymph nodes. Cancer has spread to more than one organ that is not near the colon and/or rectum or into the lining of the abdominal wall.
staging (STAY-jing)
Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body. It is important to know the stage of the disease in order to plan the best treatment.
submucosa (sub-myoo-KOH-suh)
The layer of tissue under the mucosa (inner lining of some organs and body cavities that makes mucus).
tissue (TIH-shoo)
A group or layer of cells that work together to perform a specific function.
tumor (TOO-mer)
An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.
ultrasound (UL-truh-SOWND)
A procedure in which high-energy sound waves are bounced off internal tissues or organs and make echoes. The echo patterns are shown on the screen of an ultrasound machine, forming a picture of body tissues called a sonogram. Also called ultrasonography.
vein (vayn)
A blood vessel that carries blood to the heart from tissues and organs in the body.
x-ray (EX-ray)
A type of radiation used in the diagnosis and treatment of cancer and other diseases. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.