Conventional (99m)Tc-(hydroxy) methylene diphosphate remains useful to predict osteosarcoma response to neoadjuvant chemotherapy: Individual patient data and aggregate data meta-analyses

BACKGROUND: The current standard of chemotherapy response evaluation holds the most important prognostic factor to be the histological assessment of the tumor necrosis of the excised lesion, but the major challenge is to find an early prognostic factor that will allow the adjuvant treatment regimen to be adjusted. The objective of this systematic review is to provide an up-to-date and unprecedented summary of the value of (99m)Technetium-methylene diphosphate or -hydroxymethylene diphosphate ((99m)Tc-MDP/HMDP) scintigraphy for the preoperative evaluation of osteosarcoma response to chemotherapy. METHODS: Studies evaluating the alteration ratio (percentage change of the Tc-99m -MDP/HMDP uptake between before and after neoadjuvant chemotherapy) to predict the histological response of osteosarcoma to chemotherapy were searched for in MEDLINE, EMBASE, and Web of Science. A meta-analysis of individual patient data (IPD) was performed to determine the optimal cut-off point from the receiver operating characteristic (ROC) curve. Additionally, aggregate data (AD) meta-analysis was performed to compare the value of (99m)Tc-MDP/HMDP scintigraphy with that of other quantitative modalities, such as dynamic magnetic resonance imaging (MRI), (201)Tl scintigraphy, and (18)F-FDG PET-CT. RESULTS: Seven studies with 154 patients were included for the IPD meta-analysis. The optimal cut-off point of the alteration ratio was 31.0%. Five studies with 123 patients were considered for the AD meta-analysis. The pooled sensitivity and specificity were 0.76 (95% CI, 0.63–0.86) and 0.89 (95% CI, 0.79–0.95), respectively. There was a significant difference between the good and poor responders in terms of the diagnostic odds ratio. The summary ROC curve demonstrated that the area under curve (AUC) was 0.892, indicating excellent diagnostic accuracy. CONCLUSION: Our findings have suggested that conventional (99m)Tc-MDP/HMDP scintigraphy remains as useful as recent quantitative modalities to predict the histological response of osteosarcoma to neoadjuvant chemotherapy.