Grand Canyon University
October 5, 2011
Staging is the process of finding out how much cancer there is in the body and where it is located. It is how the doctor learns the stage of a person's cancer. Doctors use this information to plan treatment and to help predict a person's outlook (prognosis). Cancers with the same stage tend to have similar outlooks and are often treated the same way. The cancer stage is also a way for doctors to describe the extent of the cancer when they talk with each other about a person’s case. Doctors need to know the amount of cancer and where it is in the body to be able to choose the best possible treatment. For example, the treatment for early stage breast cancer may be surgery and radiation, while a more advanced stage of breast cancer may need to be treated with chemotherapy, too. Doctors also use the stage to help predict the course a cancer is likely to take. For most cancers, the stage is based on 3 main factors, T, N, and M: ·T: is based on the size of the original (primary) tumor and whether or not it has grown into nearby tissues ·N: whether or not the cancer has spread to the nearby lymph nodes ·M: whether or not the cancer has spread to distant areas of the body Not all cancers are staged this way. Often this is because they grow and spread in a different way than most tumors. For example, leukemias (cancers of the blood) affect the blood and bone marrow throughout the body, and so are not staged based on these factors. Cancers in or around the brain are also not staged using the TNM system, since these cancers tend to spread to other parts of the brain and not to lymph nodes or other parts of the body. Doctors gather different types of information about a cancer to figure out its stage. Depending on where the cancer is located, the physical exam may give some clue as to the extent of the cancer. Imaging tests like x-rays, CT scans, MRIs, ultrasound, and PET scans may also provide information about how much and where cancer is in the body. Often, biopsy is needed to confirm the diagnosis of cancer, and to find out if an abnormal spot on an imaging test is really cancer spread. A biopsy involves taking out tumors or pieces of tumors and looking at them under the microscope. Samples can be removed either during surgery or during less invasive biopsy procedures. The different techniques used to remove and examine samples are described in our Surgery document. All staging is done at the time of diagnosis, before any treatment is given. There are 2 major types of staging. This is an estimate of how much cancer there is based on the physical exam, imaging tests (x-rays, CT scans, etc.), and tumor biopsies. For some cancers, the results of other tests, such as blood tests, are also used in staging. The clinical stage is a key part of deciding the best treatment to use. It is also the baseline used for comparison when looking at the cancer's response to treatment. Pathological staging (also called surgical staging) relies on information obtained during surgery. Often this is surgery to remove the cancer and nearby lymph nodes, but sometimes surgery may be done to look at how much cancer is in the body and remove tissue samples. In some cases, the pathologic stage may be different from the clinical stage (for example, if the surgery shows the cancer has spread more than it was thought to have spread before surgery). The pathological stage gives the health care team more precise information that can be used to predict treatment response and outcomes (prognosis). At one time there were many different systems used to stage cancers, and sometimes different systems were used to stage the same type of cancer. But many of these systems did not give doctors very useful information. The American Joint Committee on Cancer (AJCC) developed the TNM classification system as a tool for doctors to stage different types of cancer based on certain...