Kaposi Sarcoma: Stages

What does the stage of a cancer mean?

For most types of cancer, the stage tells how much cancer there is and how far it has spread in the body. Your healthcare provider uses exams and tests to find out the size of the cancer and where it is. These can also show if the cancer has spread to nearby areas or other parts of the body. The stage of a cancer is often one of the most important things to know when deciding how to best treat it.

What are the stages of Kaposi sarcoma?

AIDS-related Kaposi sarcoma (KS) is the most common type of KS in the U.S. The staging system used to describe it is somewhat different than the systems used for most other types of cancer. That’s because it takes into account factors other than the cancer itself.

Most healthcare providers use the KS staging system from the AIDS Clinical Trial Group of the National Institutes of Health. This system groups KS based on three factors that are labeled with the letters T, I, and S:

  • T is for the extent of the tumor in the body.

  • I is for the health of the immune system. This is measured by the CD4 cell count in a blood test.

  • S is for the extent of systemic illness in the body. This is how sick the HIV or KS is making the person.

Healthcare providers divide each of these factors into one of two subgroups where 0 stands for a lower risk of problems or good risk, and 1 stands for a higher risk of problems or poor risk.

Here's what the staging groups then mean:

Tumor status

  • T0. KS is only in the skin, only in the lymph nodes, or in both. There might be a little KS in the mouth, but the lesions are flat and mostly on the roof of the mouth.

  • T1. KS lesions are widespread. There may be swelling or sores due to the tumor, many lesions in the mouth, raised lesions, or KS in other organs in the body, like the liver, intestines, stomach, or lungs.

Immune system status

  • I0. CD4 cell count is 200 or more cells per mm3 (cubic millimeter).

  • I1. CD4 cell count is lower than 200 cells per mm3.

Systemic illness status

  • S0. These are true:

    • You have no history of other infections due to a weakened immune system (called opportunistic infections).
    • You have no history of fungal infection of the mouth (called thrush).
    • You have no B symptoms. These are unexplained fever, night sweats, unexpected weight loss of more than 10%, or diarrhea lasting for at least 2 weeks.
    • You are up and about most of the time and can take care of yourself.

  • S1. This means:

    • You have systemic illness, such as a history of opportunistic infections, thrush, or another HIV-related disease, like lymphoma.
    • You have one or more B symptoms.
    • You have a limited ability to do daily tasks and take care of yourself.

These factors are then combined to assign an overall risk group: good risk or poor risk. Because HIV treatment works very well, the immune status (I) has become less important in figuring out the risk group.

Good risk might be written as any of these: T0 S0, T1 S0, or T0 S1.

Poor risk is written as T1 S1.

Talking with your healthcare provider

Once your cancer is staged, talk with your healthcare provider about what the stage means for you. Make sure your stage is explained to you in a way you can understand. Ask questions and talk about your concerns.