Stages of cancer

Staging is an estimate of how much cancer is in your body based on a physical exam, biopsy results and imaging tests. It’s the essential step in determining if a cancer has spread and how it will be treated. Not all cancers are staged the same way. The TNM staging system is used most often and typically based on three key pieces of information:

T = main tumor (its size and/or whether it has grown into nearby areas) N = whether the cancer has spread to nearby lymph nodes

M = whether the cancer has metastasized to other organs of the body

Letters and/or numbers after the T, N and M give more details about each of these factors. In general, the lower the number, the less invasive the cancer. A higher number designates a more advanced cancer.

O: Abnormal cells have not invaded neighboring tissue. Some cancers

never progress beyond this stage.

I: Cancer is found only where it started (localized).

II: Cancer has spread to nearby tissue but not lymph nodes.

III: Cancer cells have reached nearby lymph nodes and may have traveled

into the bloodstream.

IV: Metastatic cancer in which the cancer cells have entered the

bloodstream and spread to distant organs.