Human tumor clonogenic assay in osteosarcoma for evaluation of clinical efficacy of anti-cancer drugs.

Twenty-three specimens (biopsied tissue, resected specimens, and resected pulmonary metastases were obtained during biopsy, radical surgery, or thoracotomy from patients with osteosarcoma. Using these specimens, human tumor clonogenic assay (standard HTCA) and cultivated HTCA (HTCA using single-cell suspensions obtained from short-term cultures) were carried out. The percentage of 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% using standard HTCA. We retrospectively analyzed the relationship between the results of HTCA and the clinical efficacy of agents such as methotrexate, adriamycin, cis-platinum, and vincristine, which are frequently prescribed for the treatment of osteosarcoma. This analysis revealed that if drugs are show to be ineffective by this test, they can be regarded as clinically ineffective against that specific tumor target, i.e., the tumor cells are refractory to those drugs. Thus, clinical use of such drugs should be avoided.