[Human tumor clonogenic assay in osteosarcoma and its clinical evaluation].

On twenty-three specimens from patients with osteosarcoma (biopsied tissue, resected specimens from primary and metastatic lesions), the human tumor clonogenic assay (HTCA: standard assay) as well as cultivated HTCA involving short-term cultivation of a single-cell suspension, was carried out. The percentage colony-forming ability, which was very small for standard HTCA, increased significantly when cultivated HTCA was performed. With cultivated HTCA, sensitivity tests were possible in 87% of the specimens, in contrast to only 28.6% with standard HTCA. Retrospective evaluation of the results obtained by cultivated HTCA with the clinical efficacy of anticancer drugs showed a true positive rate, 66.7%, and a true negative rate, 88.9%. This analysis revealed that drugs shown to be ineffective and that tumor cells are refractory to those drugs, so that clinical use of such drugs should be avoided.