Assessment of chemotherapy-induced changes in bone sarcomas: Clinical experience with Tc-99(m)-MDP three-phase dynamic bone scintigraphy

The aim of this study was to evaluate the value of three-phase dynamic bone scintigraphy (TPBS) in the assessment of the response of bone sarcomas to pre-operative chemotherapy and to correlate serial scintigraphic changes wi th histological findings. The study group comprised 27 patients (osteogenic sarcoma, n = 20; Ewing's sarcoma, n = 5; malignant fibrous histiocytoma, ( n = 2) with a mean age of 19.2 years. All patients received (99T)c(m)-methy lene diphosphonate TPBS before and after pre-operative chem otherapy. Each phase of the imaging procedure was interpreted qualitatively and quantitati vely. The percentage of tumour necrosis was analysed on resection materials following surgery. Histologically, 12 patients were non-responsive (tumour necrosis less than 90%) and 15 patients were responsive (tumour necrosis m ore than 90%). A decrease in the tumour blood flow ratio and extension were the most notable findings in the responders. The moan change in the tumour blood flow ratio following therapy was 58.7 +/- 8.3% and 19.9 +/- 26.6% (P < 0.005) in responders and non-responders respectively. The accuracy of th ree-phase imaging and static bone scintigraphy was 88% and 74% respectively Since bone scintigraphy is a valuable technique owing to its ability to de tect distant metastases in clinically early disease, TPBS should be helpful in monitoring therapy effects without any additional cost or radiation dos e. ((C) 1999 Lippincott Williams & Wilkins).