After anal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the anus or to other parts of the body.
The process used to find out if cancer has spread within the anus 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 may be used in the staging process:
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. For anal cancer, a CT scan of the pelvis and abdomen may be done.
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.
Endo-anal or endorectal ultrasound
A procedure in which an ultrasound transducer (probe) is inserted into the anus or rectum and 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.
The following stages are used for anal cancer:
In stage 0, abnormal cells are found in the innermost lining of the anus. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.
Pea, peanut, walnut, and lime show tumor sizes.
In stage I, cancer has formed and the tumor is 2 centimeters or smaller.
In stage II, the tumor is larger than 2 centimeters.
In stage IIIA, the tumor may be any size and has spread to either:
In stage IIIB, the tumor may be any size and has spread:
In stage IV, the tumor may be any size and cancer may have spread to lymph nodes or nearby organs and has spread to distant parts of the body.