Ewing Sarcoma: Stages

What does stage of a cancer mean?

The stage of a cancer is how much and how far the cancer has spread in the body. Exams and tests can show the size of the cancer and where it is, as well as if the cancer has grown into nearby areas or if it has spread to other parts of the body. The stage of a cancer is one of the most important things to know when deciding how to treat the cancer.

What are the stages of Ewing sarcoma?

Different staging systems can be used for Ewing sarcoma.

AJCC TNM staging system

Ewing sarcomas of the bone can be staged with the same staging system that’s used for other types of bone cancers. This system is known as the American Joint Commission on Cancer (AJCC) TNM staging system. The stage of bone cancers (including Ewing sarcoma) is based on four key pieces of information:

  • T describes the size of the tumor and if it is in different areas of the bone.

  • N describes whether the cancer has reached nearby lymph nodes. Thisis rare for bone tumors.

  • M describes whether the cancer has spread (metastasized) to far parts of the body.

  • G is the grade of the tumor. This is how the cancer cells look under a microscope. A higher grade cancer is more likely to grow and spread quickly if not treated.

These four factors are combined to give an overall stage of the bone cancer. This can range from stage I (the least advanced) to stage IV (the most advanced).

All Ewing sarcomas are considered to be high grade. So, they’re at least stage III in this system. If the cancer has spread to other parts of the body, it’s considered a stage IV cancer.

Localized versus metastatic cancer

For practical purposes (including deciding on treatment), healthcare providers use a simpler system. This divides Ewing tumors into two groups:

  • Localized cancer. The cancer seems to be only in the tissue (such as bone or muscle) where it started or in nearby tissues. But it doesn’t seem to have spread to other parts of the body based on imaging tests (and bone marrow biopsies). Even if imaging tests don’t show cancer in other parts of the body, it's possible that small amounts of cancer may have spread there. This is why chemotherapy, which can kill cells anywhere in the body, is an important part of the treatment for Ewing sarcoma.

  • Metastatic cancer. This cancer has spread from where it started to other parts of the body. These can include the lungs, other bones, or bone marrow. Less often, it spreads to the lymph nodes or the liver. 

Talking with your healthcare provider

Once the cancer is staged, your healthcare provider will talk with you about what the stage means for treatment. Make sure to ask any questions or talk about your concerns.