Staging and therapy monitoring of multiple myeloma by 99mTc-sestamibi scintigraphy: a five year single center experience

The aim of the present study was the evaluation of the diagnostic value of 99mTc-sestamibi (MIBI) in the detection of bone marrow involvement in patients suffering from multiple myeloma (MM) and its possible role in the follow-up. Between 1998 and 2003, 68 patients with MM and 42 pts with monoclonal gammopathy of undetermined significance (MGUS) were consecutively enrolled in this study. 51/68 MM patients had active disease (AD), 11/62 were in complete remission (CR) and 6/68 in partial remission (PR) after chemotherapy. 18 patients with MM repeated a 99mTc-MIBI scintigraphic study at least 2 months after high-dose chemotherapy. All the scans were scored semi quantitatively according to extension and intensity of tracer uptake. All MGUS pts had a negative 99mTc-MIBI. As far as the MM pts are concerned, 54/68 (49%) pts (48 with AD, 5 with PR and 1 with CR) had a positive 99mTc-MIBI scan, while the 99mTc-MIBI scan was negative in 14/68 pts (10 with CR, 1 with PR and 3 with AD). The overall sensitivity of the 99mTc-MIBI scintigraphy was 92%; specificity was 96%. In the follow up of the pts treated with chemotherapy 99mTc-MIBI closely paralleled the activity of myeloma bone disease. In conclusion, these results indicate that 99mTc-MIBI scintigraphy closely reflects myeloma disease activity in the bone marrow, and that a negative 99mTc-MIBI scan in patients with suspected MM clearly, though not absolutely, indicates absence of disease or clinical remission. The results of this study suggest a clear diagnostic value of 99mTc-MIBI scintigraphy in patients with MM and its potential role during the follow-up for the monitoring of MM bone disease.