Staging

Once a patient has been diagnosed with cancer, it is important for the physician to evaluate the extent of the disease and identify where the cancer began, how big it is and whether it has spread within the body. The physician may use imaging, biopsies and surgery to determine the true extent of the disease. This process is referred to as staging, and the goal is to put patients with similar prognoses and treatments into the same staging group which determines their treatment. Anatomic staging is applicable to almost all cancers except for most forms of leukemia which are not anatomically localized like other cancers.

TNM Staging

TNM staging is generally used for most types of solid tumors:

• The T stands for “tumor”. To determine the T stage of a tumor, a physician will evaluate the size of the primary tumor (site where the cancer started) and whether it has invaded any of the adjacent tissue.
• The N stands for “node” and refers to lymph nodes that are near the site of the primary tumor. As a tumor grows, it is possible that microscopic cells have broken off and entered the lymphatic system. The N stage of a cancer is determined by the presence or absence of these cancer cells in the adjacent lymph nodes.
• The M stands for “metastasis”.  If cells from the cancer that started in one location in the body travel and implant into another organ or structure such as the liver, bone or lung, then it is referred to as distant metastatic disease.

Overall Stage Grouping or Roman Numeral Staging

Once the TNM stage has been established, a patient’s cancer will often be assigned a stage with a Roman numeral from I through IV. In general, a stage I cancer is a small, localized cancer that is usually curable, while stage IV generally denotes cancer that has spread to one or more distant metastatic site(s). Stage II and III cancers are typically large or locally advanced and may have lymph node involvement. More specific descriptions for each of these stages are available for each individual type of cancer.

Treatment

Cancer is treated with surgery, radiation therapy and chemotherapy. Each of these modalities may be used alone or in combination with others. The stage, along with other factors such as general health, patient preferences and results of biochemical tests on the cancer cells will contribute to determining a patient's prognosis and treatment.

Prognosis

It is important to know that while staging is important for guiding treatment and estimating prognosis, it certainly does not reflect the entire picture. A cancer prognosis associated with a cancer stage is only a general guide, not a guarantee. There is considerable variability in outcome for every type and stage of cancer. Factors that may also impact prognosis:

• The type of cancer: For example, a stage II non-small cell lung cancer has a different prognosis than a stage II cervical cancer.
• The timing of the metastases: For instance, a patient with kidney cancer and a single site of metastasis that can be removed surgically and which presented several years after the initial surgical removal of the kidney (nephrectomy) has a different prognosis than a patient who developed metastases immediately after nephrectomy.
• The location of the metastases: Specialized methods are available for treatment of metastases such as those in the bone, liver or brain.
• New treatments are always under development: If a new treatment becomes available, then some sub-group of patients within a certain stage may suddenly have a much better prognosis.