[Comparative x-ray and nuclear medical studies of osteosarcomas to evaluate the effectiveness of preoperative chemotherapy].

In 16 patients with a long bone osteosarcoma treated after the therapy regimen of COSS 80/82 (Cooperative Osteosarcoma Study) the tumour response to preoperative chemotherapy was assessed by conventional roentgenograms (plain films, tomograms, angiograms). The histological grade of regression determined in the operative specimen was used as a reference for the extent of tumour devitalisation. By their different typical roentgenological course the osteosarcomas with a very good and those with a rather poor response could be correctly identified (100%). On following the clinically used differentiation between "good responders" (histological grades I to III) and "poor responders" (grades IV to VI) the corresponding classification of these tumours by roentgenograms and functional scintigraphic imaging was found to be correct in 94% of the cases. The coincidence of the correct as well as the false results in both radiological methods was as high as 100% if those osteosarcomas showing only a "medium response" in their roentgenograms were added to the clinical group of good responders. There were no fundamentally discrepant results obtained by each of the two radiological techniques. With the combined workup of the roentgenological and the scintigraphic material any incorrect preoperative estimation of tumour regression with a harmful influence on therapy (date and type of surgery, mode of postoperative chemotherapy) could be avoided.