How is Cancer Staged?

In my practice I am often faced with difficult questions regarding how the stage of cancer is reached by the medical field, and what that means for a patient’s health and prognosis. Here are some explanations you may find helpful, as this can be a diffcult topic to address.

The term malignancy describes cells that have become so deviant that they ignore all normal interactions with their neighboring cells. They grow wild, invading nearby organs and spreading to distant ones through lymphatic channels or through the bloodstream. Ultimately, that is how cancers kill people—by invading other critical structures and choking off life.

All cancers are staged or categorized on a scale of I through IV. Stage is set at the time of diagnosis. Once the stage of cancer is set, it never changes; a cancer cannot be restaged. Some general rules of cancer staging apply to all cancer types. However, each type has particular criteria that define the different stages for that organ. For example, Stage I cancers are confined to the organ where they originated. Stage II cancers typically have spread to the next soft tissue area next to the site of origin. Stage III represents a cancer that has spread to the next region of the body or to lymph nodes in the same region. Finally, Stage IV denotes cancers that have spread to distant organs or invaded all the way through surrounding organs.

As an example, Stage I uterine cancer means the cancer is confined to the uterus. A stage II uterine cancer has spread into the cervix. For stage III, the cancer has either spread to the ovaries, pelvis, or surrounding lymph nodes. Stage IV means the cancer has spread to other organs like the lungs, bones, liver, or brain. It can also mean the cancer has grown from the uterus into the bladder or rectum. In any case, the stage correlates with the cancer prognosis, so that a higher stage cancer has a greater chance of returning and thus a worse prognosis.

Take a look at the video below, which illustrates how cancer invades cells and spreads. It also explains the difference between precancer and cancer, which is commonly misunderstood.