To apply safely an aggressive chemotherapy regimen like CESS 81 requires 
intensive supportive care. Bleomycin is evaluated as part of the protocol for 
treatment of primary Ewing's sarcoma. Bleomycin might cause pulmonary fibrosis 
at higher cumulative doses as toxic effect directly to the lungs or most likely 
in addition by the formation of vascular microthrombi. A randomized study is 
designed to evaluate if pulmonary changes due to Bleomycin can be prevented 
using heparin. As severe bone marrow depression is anticipated the effect of 
lithium on the leucocyte nadir is also subject of a randomized study.