Response of DNA ploidy to chemotherapy in primary and metastatic lesions in human osteosarcomas

Primary and pulmonary metastatic and pulmonary metastatic tumors (two synchronous and seven metachronous metastases) in nine patients with osteosarcomas were studied by DNA cytofluorometry. All patients were treated with both pre and postoperative chemotherapy. The results showed that all five diploid osteosarcomas and three of the four aneuploid tumors did not markedly change their ploidy pattern after preoperative chemotherapy, and had almost the same ploidy patterns as the pulmonary metastatic lesions. Those eight tumors showed poor histologic response and chemoresistance by the doxorubicin binding assay. Only one aneuploid osteosarcoma showing good histologic response and chemosensitivity changed its ploidy pattern to diploid, with the disappearance of aneuploid tumor cells and its synchronous pulmonary metastatic tumor also showed conversion to a diploid pattern with massive tumor necrosis. It is evident that those tumors showing no change in their ploidy pattern after chemotherapy were resistant to the chemotherapy. Therefore, we conclude that regardless of whether the pulmonary metastatic tumors were synchronous or metachronous, they showed the same change in their ploidy pattern as well as their chemosensitivity as the primary human osteosarcoma from which they were derived.