Once you have Ewing's Sarcoma do you always have it?

Answer 1

Ewing's Sarcoma is a malignant disease of the bones. While spontaneous regression of malignancies (in general) is an acknowledged although poorly understood phenomenon, the overwhelming majority (I would say all) of cancers are fatal unless treated successfully. This is because one of the hallmark traits of malignant tumors is their ability to undergo unrestrained growth even in the absence of growth-promoting factors.

With successful treatment, the patient will no longer have Ewing's sarcoma (the malignant cells & tumors) in their body. However, the five-year survival rate of Ewing's sarcoma patients (after treatment) who had a localized tumor is 70% on average. For patients with a metastatic tumor (one that had spread to various other sites) the five-year survival rate is 20-30%.