Morphological changes in osteosarcoma after chemotherapy--COSS 80.

Forty-five osteosarcomas were investigated by special methods such as preparation of undecalcified bone tumor tissue, imprint cytology, histochemistry, and quantitative analysis. The morphological regression grades and their relation to chemotherapy are reported by Salzer-Kuntschik et al. (1983). The results presented demonstrate that smaller osteosarcomas respond more favorably than larger tumors. The function of bone-tumor cells, e.g., osteoid production, trabecular tumor bone formation, and mineralization, seems to be more important for the sensitivity to chemotherapy than the cell polymorphism. The estimation of bone-tumor morphology in at least two total areas of the bone tumor is essential in borderline cases (grade III/grade IV). Imprint cytology is very helpful for rapid estimation of the effect of therapy and the demonstration of cellular polymorphism. At the moment, we are not able to determine the effect of chemotherapy from the first biopsy before starting chemotherapy.