This page was reviewed under our medical and editorial policy by
Bradford Tan, MD, Chair, Department of Pathology and Laboratory Medicine, City of Hope Atlanta, Chicago and Phoenix
This page was reviewed on September 25, 2022.
Staging plays an important role in both diagnosing and treating cancer. Staging refers to the way doctors describe the characteristics of an individual cancer. These characteristics include:
This information helps guide treatment and may also be used to estimate survival rate, the chance that the cancer may return after treatment and which clinical trials may be an option.
Staging is typically performed at diagnosis after a series of tests. Although the cancer may change or progress, the stage initially assigned usually doesn’t change. A new classification may be added after treatment or if the cancer recurs.
A few methods are used to stage cancer, named for when in the diagnosis/treatment continuum the staging is performed. These include clinical, pathological and post-therapy staging.
Clinical staging: Determining a cancer’s stage before treatment is called clinical staging. It may draw on information from a patient’s health history, physical exam and tests such as imaging, blood tests and previous biopsies. This helps the oncology team plan treatment and form an educated opinion of the prognosis.
Pathological staging: If treatment begins with surgery to remove cancer, doctors will consider any new information gained during the procedure in order to determine the pathological or surgical stage. Because this information adds to what was discovered during the clinical staging, this staging is considered more accurate.
Post-therapy staging: If radiation therapy, hormone therapy, chemotherapy, immunotherapy or other therapies are administered instead of surgery as the initial treatment, the cancer may be assigned a post-therapy or post-neoadjuvant therapy stage. Post-therapy staging means the staging was performed after treatments used instead of surgery. Post-neoadjuvant therapy staging means it was performed after treatment designed to shrink a tumor before surgery.
Most cancers are assigned one of four stages, ranging from 1 to 4, with the lowest stage describing early and small tumors and the higher stages categorizing cancers that have progressed and spread. Doctors may use Roman numerals for each stage instead of numbers, but they mean the same thing. Stages 1, 2, 3 and 4 may be written as I, II, III and IV.
Staging for some cancers, such as breast cancer, includes stage 0 or carcinoma in situ. With these cancers, staging ranges from 0 to 4. Stage 0 is used to describe a clump of abnormal cells that hasn’t spread into neighboring tissue or elsewhere, sometimes called pre-cancer. Surgery often is able to remove such growths.
Staging varies with the type of cancer. The term stage 5 isn’t used with most types of cancer. Most advanced cancers are grouped into stage 4. An exception is Wilms tumor, or nephroblastoma, a childhood cancer that originates in the kidneys. Stage 5 Wilms tumors are those that affect both kidneys.
For the majority of adult cancers, the TNM system is used to determine staging. It categorizes cancer progression for most solid tumors that spread to other sites in the body. Other staging systems are used for cancers that don’t fit those criteria.
TNM stands for tumor, node and metastasis. The system uses numbers and letters to describe these three aspects of a cancer:
Clinical or pathological stages may be designated in the TNM system by a lowercase “c” or “p” before the capital “T.” Similarly, if a cancer is restaged, a lowercase “y” may be added if this occurs post-therapy or a lowercase “r” may be added for restaging when cancer recurs.
Grade refers to how normal or abnormal the cells and tissue structure in the tumor appear when examined under a microscope. The amount of cell division seen in the sample also is considered. The pathologist checks tumor samples gathered via biopsy or during surgical removal of a tumor. If it resembles healthy tissue with normal structure and distinct groups of different types of cells, it’s considered to be “well differentiated,” and the tumor is low-grade. Low-grade tumors generally grow slowly and may lead to a better prognosis.
Samples with cells and tissue structure that appear abnormal are termed “poorly differentiated,” and the tumor is considered high-grade. These cells typically grow and spread faster and may need immediate, more aggressive therapy.
Grade scores run from low-grade, G1, to undifferentiated, G4. When the grade can’t be decided, the tumor is given a score of GX.
Some cancers have their own grading system. Prostate cancer, for example, is described using the Gleason scoring system, and breast cancer is characterized by the Nottingham grading system.
Biomarkers are substances found in high levels in cancer patients. These tumor markers may be found in blood, urine, body tissues or tumors, and they may influence staging with some cancers. One example is that men with prostate cancer have high levels of the prostate-specific antigen (PSA). For some cancers, these markers may be more useful than facts garnered from other staging factors when deciding treatment.
Some tests may indicate whether tumor cells have certain chemical receptors shown to respond to certain treatments, such as drugs that target those receptors or the substances to which they attach. Breast cancer patients may be tested to determine whether cancer cells have receptors for the hormones estrogen and progesterone. The genetics of the tumor may help the care team determine which treatments to recommend. Researchers have discovered many genes involved in various cancers, and drugs have been developed to specifically target many of these cancers.
A patient’s age, the tumor location and the type of cell from which the cancer grew are some other factors that may influence cancer staging and treatment.
Other staging systems are used for cancers that don’t fit well into the TNM system. In addition to prostate and breast cancer, these include:
Blood cancers: These cancers usually don’t form solid tumors that can be measured. Lymphoma, leukemia, multiple myeloma and other cancers that form in blood or lymph cells fall into this group, each of which has its own staging system.
Cancers of the brain and spinal cord: These cancers are typically confined to the central nervous system and don’t metastasize throughout the body. There’s no one general system to stage these cancers.
Gynecological cancers: Internationally, a system designed by the International Federation of Obstetrics and Gynecology (FIGO) is used to stage cancers of the female reproductive system. Though this system doesn’t follow the TNM categories, it has five similar overall stages, from 0-4.
Childhood cancers: Pediatric oncologists generally use staging systems unique to each pediatric cancer.
