The Correlation of Tc-99m MIBI Scintigraphy and Histological Response in Determining the Percentage of Tumor Necrosis in Osteosarcoma after Preoperative Chemotherapy
Thipachart Punyaratabandhu MD*, Surang Wittayawongsaruji MD*, Samart Rajchadara MD**, Voranuch Thanakit MD***, Supichai Charoenvareekul MD*, Narin Khunkitti MD*, Thawee Songpatanasilp MD*
Affiliation : * Musculoskeletal Oncology Unit, Department of Orthopaedics ** Nuclear-medicine Unit, Department of Radiology, Phramongkutklao Hospital *** Department of Pathology, Faculty of Medicine, Chulalongkorn University
Purpose: The most important prognostic factor of osteosarcoma is the percentage of tumor necrosis. Only
well trained and experienced musculoskeletal pathologists can count and assess the percentage of tumor
necrosis from the resected specimens. The purpose of the present study was to characterize the correlation
of Tc-99m MIBI scintigraphy for assessing the percentage of tumor necrosis using postoperative
histology as a gold standard.
Material and Method: During September 2002 to August 2004, nine consecutive patients with the
diagnosis of conventional osteosarcoma were included in the present study. The osteosarcoma protocol
comprises 3 courses of doxorubicin and cisplatin preoperatively followed by wide resection of tumors
and another 3 courses of postoperative chemotherapy. The Tc-99m MIBI scintigraphy examination was
carried out before commencing chemotherapy and after completing preoperative chemotherapy. The
tumor uptake was measured using the tumor to the background ratio (TBR). Comparison of TBR before
and after preoperative chemotherapy was used to calculate the alteration ratio which was reported in
terms of percentage. All of the resected specimens were sent to the pathological department. The
histological assessment of the response to chemotherapy was performed using the standard technique
according to the current practice of osteosarcoma from the Mayo Clinic. The percentages of tumor
necrosis from histology were also reported.
Results: The analysis of the correlation between the reduction of tracer uptake and the postoperative
histological response was performed. The correlation and linear regression analysis showed that the two
methods had a significant correlation (R = 0.75) regression coefficient (1.172) with p = 0.020 and
0.043, respectively.
Conclusion: The present study showed that Tc-99m MIBI scintigraphy had a significant correlation
with percentage of tumor necrosis from histology. This technique can be used to predict the response
of osteosarcoma after preoperative chemotherapy.
Keywords : Osteosarcoma, Tumor necrosis, Tc-99m MIBI scintigraphy
