ON THIS PAGE: You will learn about how doctors describe a cancer’s growth or spread. This is called the stage. Use the menu to see other pages.

What is cancer staging?

Staging is a way of describing where the tumor is located, if or where it has spread, and whether it is affecting other parts of the body.

Doctors use diagnostic tests to find out the cancer’s stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor recommend the best kind of treatment and can help predict a person’s prognosis, which is the chance of recovery. There are different stage descriptions for different types of cancer.

Although there is no official staging system for Ewing sarcoma, the following criteria help doctors describe Ewing sarcoma and work together to plan the best treatments:

• Localized Ewing sarcoma. The tumor is only found by physical examination or by imaging in the primary site or in lymph nodes next to the tumor. Lymph nodes are the small, bean-shaped organs that help fight infection. The tumor has not spread beyond that area.

• Metastatic Ewing sarcoma. The tumor has spread from the primary site where it began to another part of the body, such as the lungs, other bones, or bone marrow. Rarely, the disease spreads to the lymph nodes, brain, or spinal cord. Doctors will be able to quickly see evidence of tumor spread in 25% of children and young adults with Ewing sarcoma when they are diagnosed. Whether the tumor has spread is the most important factor used to determine a person’s treatment options and prognosis.

• Recurrent Ewing sarcoma. Recurrent Ewing sarcoma is a tumor that has come back after treatment. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.

Additionally, your child's doctor will evaluate several factors at the time of your child's diagnosis to help predict their prognosis. These factors include:

• The site of the tumor. Patients with Ewing sarcoma in the distal extremities have the best prognosis. Patients with Ewing sarcoma in the proximal extremities have an intermediate prognosis, followed by patients with Ewing sarcoma in central or pelvic sites.

• Tumor size or volume. Larger tumors, which are those with volumes of 100 milliliters (ml) or 200 ml and/or a single dimension greater than 8 centimeters, tend to occur in unfavorable sites.

• Age. Infants and younger patients tend to have a better prognosis than older patients (those age 15 or older).

• Sex. Girls with Ewing sarcoma have a better prognosis than boys.

• Serum lactate dehydrogenase (LDH). Elevated LDH is associated with a worse prognosis.

• Metastases. The presence or absence of metastatic disease is the single most important predictor of prognosis.

• Other factors at the time of diagnosis. These include the presence of bone fracture caused by the cancer spreading; previous treatment for another cancer; tumor chromosomal alterations; and detectable circulating tumor DNA (ctDNA) in the blood. Patients who have detectable ctDNA at the time of diagnosis typically have a worse prognosis as compared to patients who do not have detectable ctDNA. One study showed that the reduction in ctDNA levels below the detection limit after 2 cycles of induction chemotherapy was associated with a better outcome than patients who had persistence of ctDNA after 2 cycles of chemotherapy.

Information about the cancer’s stage will help the doctor recommend a specific treatment plan. The next section in this guide is Types of Treatment. Use the menu to choose a different section to read in this guide.