The domain of hemato-oncology is characterized by a complex and data-intensive treatment and the involvement of geographically distributed institutions (e.g. oncological ward, central commission, external panels) in the context of protocol-directed trials. Current research efforts in this domain (e.g. [1-3]) focus on specialized subtasks such as chemotherapy calculation and toxicity monitoring, but fail to support inter-application data flow and coordination aspects which have been identified as essential for integration in heterogeneous and distributed clinical environments (e.g. [4,5]). Therefore, at Leipzig University, the distributed workflow system HEMATOWORK, which has explicit knowledge about the oncological treatment and the associated communication paths between the involved institutions, is currently developed. In particular, HEMATOWORK intends to support the following basic tasks: