Staging attempts to distinguish people with localized from those with metastatic disease. The most common areas of metastasis are the lungs, bone and bone marrow with less common areas of metastasis being the lymph nodes liver and brain. The presence of metastatic disease is the most important prognostic factor in Ewing's Sarcoma with the 5 year survival rate being only 30% when metastasis is present at the time of diagnosis as compared to a 70% 5 year survival rate with no metastasis present. Another important prognostic factor is the location of the primary tumor; proximal tumors (located in the pelvis and sacrum) are worse prognostic indicators as compared to more distal tumors. Other factors associated with a poor prognosis include a large primary neoplasm, older age at diagnosis (older than 18 years of age) and increased lactate dehydrogenase (LDH) levels.