Ewing Sarcoma

Origin and Causes

Ewing's sarcoma is the second most common primary malignant bone tumor in children and adolescents. It occurs more frequently in the second decade, but can also affect older patients. Ewing's sarcoma can also be found in soft tissues. To date, no risk factors explaining the occurrence of Ewing's sarcomas have been identified.

 

Symptoms and Signs

Ewing's sarcoma often affects the metaphysis of long bones (i.e. femur), but can also present in any other bone in the body. The first symptoms are often a progressive pain followed by swelling in the region affected by the sarcoma. A mass in the soft tissues may also be palpable. Some patients may present with pulmonary or bone metastases at diagnosis.

Diagnosis

When a sarcoma is suspected, the initial evaluation includes either a CT scan or MRI. The diagnosis is made by biopsy of the suspected area. The biopsy can be performed in the operating room or by the radiology team under local anesthesia. The pathology team will then confirm the diagnosis after analyzing the samples. The diagnosis of Ewing's sarcoma is often confirmed by the presence of gene rearrangements involving EWSR1. The evaluation can be completed with a chest CT scan and a PET scan.

Treatment

When Ewing's sarcoma is localized, the preferred treatment is surgery to remove it all. Since Ewing's sarcoma is an aggressive cancer that can cause metastases, chemotherapy before surgery and after surgery is necessary. The most commonly used chemotherapy protocol is VDC (Vincristine-Doxorubicin-Cyclophosphamide) alternated with IE (Ifosfamide-etoposide). Radiation therapy may sometimes be necessary in treatment.

In the event of Ewing's sarcoma relapse, chemotherapy is offered with the goal of controlling symptoms and disease progression. The preferred agents are: Cyclophosphamide-Topotecan, Temozolomide-Irinotecan, Ifosfamide, gemcitabine-docetaxel, cabozantinib, or regorafenib. Clinical trials may also be explored.

 

Follow-up

After surgery, patients with Ewing's sarcoma will be closely monitored due to the risk of recurrence (when cancer returns). The follow-up will be every 3 months for the first two years, then every 6 months up to 5 years. Afterwards, visits will be spaced out every year up to 10 years.