Histomorphometric changes of osteosarcoma after chemotherapy. Correlation with 99mTc methylene diphosphonate functional imaging.

An investigation to correlate histologic changes in 12 osteosarcoma specimens from patients undergoing chemotherapy was performed using functional images of regional 99mTc methylene diphosphonate (MDP) plasma clearance rates assessed from dynamic bone scintigraphies taken during chemotherapy. Residual tumor cell viability was determined by microscopic examination of multiple thin sections from surgical specimens and quantitated by histomorphometry. Regions that showed decreases in 99mTc MDP plasma clearance of more than 20% were associated with areas of necrotic tumor, and regions that showed absent decline or increasing clearance rates were associated with high residual cell viability and incomplete response to chemotherapy. Therefore, functional bone scintigraphy allows an objective presurgical assessment of tumor response to chemotherapy.