Assessment of chemosensitivity in patients with malignant bone and soft tissue tumors using thallium-201 scintigraphy and doxorubicin binding assay

This study was performed to compare the accumulation of thallium (TI) -201 which is correlated with malignancy and the doxorubicin binding ability, wh ich is correlated with chemosensitivity, in nine patients who received preo perative chemotherapy with doxorubicin and cisplatin. (Tl)-201 scintigraphy was performed at 15 minutes (early image) and 3 hours (delayed image) afte r injection of 111 MBq of Tl-201. The change of degree of the radionuclide uptake between the early and delayed images was evaluated before and after preoperative chemotherapy. The doxorubicin binding ability (%DB) to nuclear DNA in living tumor cells isolated from biopsy materials was assessed by d oxorubicin binding assay. The histologic response to preoperative chemother apy was evaluated by the percentage of tumor necrosis. Before preoperative chemotherapy no changes of Tl-201 uptake between the early and delayed imag es was defected in any tumors. Five patients, who had no change of Tl-201 u ptake after preoperative chemotherapy, showed a poor histologic response an d had a %DB ranging from 10% to 70% (mean: 36.0%). The other four patients, who had a %DB greater than 90%, showed a good histologic response. All of these four patients had decreased Tl-201 uptake after preoperative chemothe rapy. This study demonstrated that doxorubicin binding assay and midcourse Tl-201 scintigraphy are useful methods to assess the response to chemothera py early in malignant bone and soft tissue tumors.