Ewing sarcoma is a rare and aggressive cancer that forms in bone or soft tissue. Doctors stage cancer based on factors like the size of the tumor and whether it has spread to distant tissues.
Ewing sarcoma affects roughly 1.7 in 1 million children. It most often develops between the ages of 10 and 20. Advances in treatment have greatly increased its survival rate in recent years.
Doctors use different staging systems for Ewing sarcoma. Knowing the cancer’s stage gives the best idea about how to treat it and what to expect.
Ewing sarcoma is an aggressive bone or soft tissue cancer. It was first described by Dr. James Ewing in
It
- arms
- feet
- hands
- chest
- pelvis
- spine
- skull
Doctors usually start the diagnostic process for Ewing sarcoma by performing a physical exam and examining your medical history. If your doctor suspects cancer, they may order:
Researchers use the results of these tests to stage Ewing sarcoma. Various staging systems are used, but the simplest way doctors classify it is by referring to it as one of the following:
- Localized: Cancer has not spread beyond the original tumor.
- Metastatic: Cancer has spread to distant body parts. About
20% of people have metastatic cancer at diagnosis. - Recurrent or relapsed: The cancer was successfully treated but came back.
The American Joint Committee on Cancer (AJCC) TNMG staging system is one of the most common systems used for bone cancer. Doctors use this system to stage many types of bone cancer. It divides cancer into stages based on the following metrics:
- Tumor: how big the tumor has grown
- Node: whether the cancer has spread to nearby lymph nodes
- Metastasized: whether the cancer has spread to distant parts of your body
- Grade: how aggressive the cancer is predicted to be
All Ewing sarcomas are given the highest G score of 3 since they’re always considered very aggressive.
| Stage | Ewing sarcoma in bone TNMG scores |
|---|---|
| 2A | • T1: tumor is smaller than 7.8 cm across • N0: cancer hasn’t spread to lymph nodes • M0: cancer hasn’t spread to distant sites • G3: cancer is grade 3 |
| 2B | • T2: tumor is larger than 7.8 cm across • N0: cancer hasn’t spread to lymph nodes • M0: cancer hasn’t spread to distant sites • G3: cancer is grade 3 |
| 3 | • T3: there’s more than one tumor in the same bone • N0: cancer hasn’t spread to lymph nodes • M0: cancer hasn’t spread to distant sites • G3: cancer is grade 3 |
| 4A | • any T: cancer is any size • N0: cancer hasn’t spread to lymph nodes • M1a: cancer has spread to the lungs but not other distant tissues • G3: cancer is grade 3 |
| 4B | • any T: cancer is any size • N1: cancer has spread to lymph nodes • any M: cancer may have spread to distant locations • G3: cancer is grade 3 OR • any T: cancer is any size • any N: cancer may have spread to lymph nodes • M1b: cancer has spread to distant locations, like the brain or other bones • G3: cancer is grade 3 |
Stage 1 is not used for Ewing sarcomas since it’s always considered to be a high grade. Other bone cancers with a G value of 1 are sometimes classified as stage 1.
Stage 2 Ewing sarcoma in bone is classified as stage 2A or 2B. Cancer in this stage is still confined to one tumor.
Ewing sarcoma in bone is classified as stage 3 if it has spread to multiple tumors in the same bone but hasn’t spread to distant areas.
Stage 4 Ewing sarcoma in bone is classified as either stage 4A or 4B. Stage 4 bone sarcoma has spread to distant parts of the body or lymph nodes.
The AJCC system for staging soft tissue sarcomas is similar to the system for staging bone cancers, but it uses slightly different values to determine which stage the cancer is in.
Soft tissue Ewing sarcoma is also always assigned a G value of 3. Here’s a look at how soft tissue Ewing sarcoma is staged when it develops in the trunk or extremities.
| Stage | Soft tissue Ewing sarcoma in trunk or extremities TNMG scores |
|---|---|
| 2 | • T1: tumor is smaller than 5.08 cm across • N0: cancer hasn’t spread to lymph nodes • M0: cancer hasn’t spread to distant sites • G3: cancer is grade 3 |
| 3A | • T2: cancer is larger than 5.08 cm but smaller than 9.9 cm across • N0: cancer hasn’t spread to lymph nodes • M0: cancer hasn’t spread to distant sites • G3: cancer is grade 3 |
| 3B | • T3 or T4: cancer is between 5.08–9.9 cm across or more than 14.98 cm • N0: cancer hasn’t spread to lymph nodes • M0: cancer hasn’t spread to distant sites • G3: cancer is grade 3 |
| 4 | • any T: cancer is any size • N1: cancer has spread to lymph nodes • M0: cancer hasn’t spread to distant sites • G3: cancer is grade 3 OR • any T: cancer is any size • any N: cancer may have spread to lymph nodes • M1: cancer has spread to distant sites • G3: cancer is grade 3 |
Cancers that develop in the tissue behind the abdominal wall need to have spread to distant tissues to be considered stage 4, but they are otherwise staged the same.
Advances in Ewing sarcoma treatment have improved the 5-year survival rate from under
- being under 10 years old
- positive response to chemotherapy
- normal blood lactate dehydrogenase levels
- tumor on an arm or leg
- smaller tumor size
The
| Stage | 5-year relative survival rate |
|---|---|
| Localized | 82% |
| Regional | 70% |
| Distant | 39% |
Ewing sarcoma is a rare type of cancer that forms in the bones or soft tissue. Doctors divide Ewing sarcoma into stages based on how far it has advanced. This helps them guide treatment decisions and predict chances of survival.
The AJCC divides Ewing sarcoma from stage 2 to stage 4. Cancer diagnosed in the early stages generally has a better outlook than cancer diagnosed later.