Utility of Tc-99m Sestamibi scintigraphy in predicting the post-surgical recurrences in patients with osteosarcoma

Full text: Anatomic modalities are not specific enough to evaluate local recurrences in the post-surgical follow up of patients with osteosarcoma. The purpose of this study was to assess the value of Tc-99m Sestamibi (MIBI) scans in the post-surgical follow up of patients with osteosarcoma. We analysed the results of 83 Tc-99m MIBI studies in 32 patients and compared these with other investigations like CT, MRI, X-ray, bone scans and also correlated with histopathology findings. Two independent observers evaluated all the scans. Sixteen out of 83 scans were found to be MIBI positive. Eleven of these 16 scans were confirmed as true positive (PPV 69%) and 5 false positive (FP). Scintiscans in 2 of these 5 patients were acquired early after surgery and in the long term follow up both became negative. The other 3 FP scans were labeled as pseudoarthrosis or graft fracture. Of the 67 negative scans, 64 were true negative (NPV 95%). Three were false negative, 2 of them were cases with MDR. It was concluded that MIBI whole body scan is a useful tool in the post-surgical follow up of patients with osteosarcoma, particularly to evaluate local or regional recurrences. A negative scan is highly predictive for no tumor recurrence. A negative baseline scan could be consistent with MDR gene expression. (author)