Ewing sarcoma (ES) (synonyms: classic Ewing sarcoma (EWS); peripheral malignant primitive neuroectodermal tumor (PPNET); Askin tumor of the chest wall; bone Ewing sarcoma; soft tissue Ewing sarcoma; soft tissue Ewing tumor; ICD-10-GM C41. 9: Bone and articular cartilage, unspecified) refers to a highly malignant (highly aggressive/very malignant) neoplasm (neoplasm) of bone (bone tumor). Ewing’s sarcoma can also form in soft tissues such as fat, muscle, connective tissue or peripheral nerve tissue. If it develops outside of and without involvement of the bone, it is called an extraskeletal or extraosseous Ewing tumor (rare).
Ewing’s sarcoma is a primary bone tumor. Typical for primary tumors is their respective course and that they can be assigned to a certain age range (see “Frequency peak”) as well as a characteristic localization (see under “Symptoms – complaints”). They occur more frequently at the sites of most intensive longitudinal growth (metaepiphyseal/articular region). This explains why bone tumors occur more frequently during puberty. They grow infiltratively (invading/displacing), crossing anatomic boundary layers. Ewing’s sarcoma often occurs in the medullary cavity of the long tubular bones.
Sex ratio: boys/men to girls/women is 1.2-1.5: 1.
Peak incidence: Ewing sarcoma occurs predominantly between the ages of 5 and 25 years – 85% in children and adolescents (median age of onset: 15 years). Soft tissue sarcomas occur primarily in older individuals.
Malignant bone tumors account for 1% of all tumor cases in adults. Ewing’s sarcoma is the third most common malignant tumor of bone after osteosarcoma (40%) and chondrosarcoma (20%) at 8%.
The incidence (frequency of new cases) in children (< 15 years) is 3 cases per 1,000,000 population per year and in adolescents (15-25 years) 2.4 per 1,000,000 population per year (in Germany).
Course and prognosis depend on the location, size, extent and stage of Ewing’s sarcoma. It is true that “the earlier the tumor is detected, the better the chances of cure”. Ewing’s sarcoma grows rapidly and destroys bone. Usually this can be seen on the first x-ray. Ewing’s sarcoma is highly malignant (highly aggressive) and metastasizes early. It mainly affects the lungs and the rest of the skeleton, the bone marrow and rarely the regional lymph nodes. Consequently, the treatment for Ewing’s sarcoma is resection (surgical removal). Neoadjuvant chemotherapy (NACT; chemotherapy before surgery) is usually given to shrink the tumor and kill any metastases (daughter tumors) that may be present. At the time of diagnosis, 20-25% of those affected already have metastases. Depending on the situation, radiotherapy may be used instead of surgery, possibly in combination with surgery. Following the removal of the Ewing’s sarcoma, chemotherapy is again administered (= adjuvant chemotherapy). The patient’s response to chemotherapy plays a decisive role with regard to prognosis.
The 5-year survival rate for localized Ewing sarcoma (≤ 200 ml tumor volume) and good response to neoadjuvant chemotherapy is between 70% and 75%. Survival in localized tumor (≥ 200 ml tumor volume) or poor response to therapy or pulmonary metastases decreases to approximately 50%. If worse, the 5-year survival rate is 20-40%.If recurrence (recurrence of disease) occurs, the 5-year survival rate is 7% for an interval < 2 years (from initial diagnosis to recurrence) and 29-30% for an interval > 2 years. Local recurrence is associated with a better prognosis.
