Combined ultrastructural, histochemical, and autoradiographic study of osteosarcoma after preoperative chemotherapy according to the COSS 80 protocol

Cytostatic effects in osteosarcomas as detected by flow cytometric DNA analysis after preoperative chemotherapy according to the COSS 80/82 protocol

A total of 20 highly malignant osteosarcomas were studied by DNA flow cytometry after preoperative chemotherapy according to the COSS 80/82 protocol to assess their nuclear DNA content and the impact of chemotherapy on DNA ploidy and proliferation. Of the cases studied, 70% revealed aneuploid DNA stem lines with a median value of 1.67, and a median S-phase proportion of 16.1%. These data differed substantially from the results of a preceding study on untreated osteosarcomas revealing a higher frequency of DNA aneuploidy, higher DNA indices, and higher proportions of cells in S-phase. The pretreated tumors also showed a distinct relation between DNA content and the grade of tumor regression. No aneuploid DNA stem line was found in the responder group-I, whereas group-V (osteosarcomas with more than 50% viable tumor tissue) consisted almost completely of aneuploid DNA populations; all tumors with more than 2 DNA aneuploids were found in the latter group. All populations with a DNA index (DI) over 2.0 were found in the nonresponder groups IV and V, where all DNA aneuploids had an S-phase above 12%. No differences in DNA ploidy or proliferation were found in the various histological subtypes of pretreated osteosarcomas. These data indicate that flow cytometric DNA measurement in osteosarcoma may not only serve as a tumor marker, but also support the evaluation of morphologically established regression grades, thereby verifying the patient's prognosis: a high DI (over 2.0), a high number of DNA aneuploids (more than 2), and a high proliferation (S-phase above 12%) seemed to indicate a poor regression of the primary lesion, which may offer a pretherapeutic way of prognostic evaluation.

Morphology of pulmonary metastases from osteosarcoma during chemotherapy

Osteosarcoma is known to metastasize rather early, and even after surgical resection of the primary metastases may occur predominantly in the lung. Administration of polychemotherapy for destruction of micrometastases has served to improve prognosis. Preoperative chemotherapy facilitates the evaluation of regression, another factor of high prognostic relevance. Morphologic analysis of pulmonary metastases developing during chemotherapy is of considerable interest on account of the potential therapy resistance of certain histologic subtypes of osteosarcoma. In the present study pulmonary metastases resected in 20 thoracotomies of 15 osteosarcoma patients were investigated by light microscopy and compared, if possible, to the respective primaries. All patients had received chemotherapy, predominantly according to the COSS 80 and COSS 82 protocols. The histologic picture of a tumor was found to change from the primary to the pulmonary metastasis, a pattern also verified in the lung metastases collected in consecutive thoracotomies from the same patient. Several different subtypes were regularly found side by side in the metastases, but generally no special sensitivity or resistance to chemotherapy could be attributed to any of these subtypes. Our results nevertheless do indicate an increased resistance of anaplastic tumor tissue. The response to chemotherapy agreed in 9 of 10 primaries with that of their metastases.

Size dependent enzyme activities of multinucleated (osteoclastic) giant cells in bone tumors

In osteoclastic giant cells of six different tumors of bones and joints (fibrous dysplasia, proliferating giant cell tumor, malignant giant cell tumor, osteosarcoma after chemotherapy, malignant synovioma and Ewing's sarcoma) activities of tartrate-resistant acid phosphatase, NADH-tetrazolium-oxidoreductase and, in three of them, of non-specific esterase are determined by enzyme histochemical methods. Quantitative microphotometry makes it possible to determine relative enzyme activities in the cut sections of giant cells of different sizes. Giant cells of the various tumors reveal similar trends: With an increase in cell size, mean extinctions of NADH-tetrazolium-oxidoreductase and non-specific esterase decrease. Mean extinctions of tartrate-resistant acid phosphatase increase in cells of medium size, whereas the large cells reveal in part low activities. An additional ultrastructural examination of the giant cells in the proliferating giant cell tumor as well as in the osteosarcoma shows morphological signs of degeneration in the large cells. Electron probe microanalysis of the proliferating giant cell tumor exhibits evidence of phagocytosis of Ca and/or Fe containing particles. The similar size dependent reaction pattern of enzymes in osteoclastic giant cells of different tumors favors the concept of a common histogenesis, i.e. a host reaction.