Prediction of final tumor response to preoperative chemotherapy by Tc-99m MIBI Imaging at the middle of chemotherapy in malignant bone and soft tissue tumors: Comparison with Tl-201 imaging

The aim of this study was to assess the predictive power of Tc-99m-MIBI scintigraphy performed in the middle of chemotherapy, for the final tumor response to chemotherapy, and compare it to that of (TI)-T-201 in malignant bone and soft tissue tumors (MBST). Sixty-eight patients with MBST underwent Tc-99m-MIBI and (TI)-T-201 scintigraphies at 15 min after tracer injection before the first, and after the third, chemotherapy cycles. After five cycles of chemotherapy and tumor resection, therapeutic effect was assessed by histopathology. Less than 90% and >= 90% necrosis were judged as poor and good response to chemotherapy, respectively. Tracers uptake ratios were calculated by dividing the lesion count density by that of the background. Tc-99m-MIBI perfusion index was also calculated. The % reduction of the perfusion index (Delta PI) and uptake ratios (Delta UR) calculated by 100 x [(prechemotherapy value - postchemotherapy value)/prechemotherapy value] were compared with histologic response. The sensitivity, specificity, and accuracy for the prediction of effective chemotherapy in Te-99m-MIBI imaging were 80%, 95%, 88% in Delta UR, and 74%, 74%, 74% in Delta PI, respectively. The area under the receiver operator characteristic curve (A(z)) of the Te-99m-MIBI-Delta UR (0.923) was significantly higher than that of Delta PI (0.809, p = 0. 025) but only marginally higher than that of the (TI)-T-201-Delta UR (0.86,5,p = 0.079). A(z) in Tl-201 (0.865) was not significantly different from that of Delta PI (0.809, p = 0.35). Tc-99m-MIBI imaging performed in the middle of chemotherapy well predicts the final tumor response to chemotherapy in patients with malignant bone and soft tissue tumors. (C) 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.