Risk assessment in high grade sarcoma patients during neoadjuvant chemotherapy using multiple tracer PET

20006 Background: Patients with high grade soft tissue sarcomas are treated with neoadjuvant chemotherapy. Sarcomas have biological features that may predict for poor outcome. Some of these features are tumor proliferation rate, level of tumor hypoxia, and upregulation of tumor drug resistance mechanisms. Methods: We have a group of specific PET imaging agents to quantify the level of activity of these tumor processes. Patients with soft tissue sarcomas receive [C-11]Thymidine (TdR) to assess cellular proliferation, [O-15] Water to quantify tumor blood flow and to serve as the input function for quantification of the other tracers, [C-11]Verapamil to assess drug resistance mechanism activity, and [F-18]Fluoromisonidazole) FMISO to quantify changes in tumor hypoxic volume in response to treatment. These studies are performed in a single PET imaging session prior to neoadjuvant chemotherapy, after the second of four cycles of therapy and in the week prior to resection. Results: An example of this complex st...