The lipophilic cationic compound
Tc-99m-tetrofosmin has been demonstrated to be a valuable tool for the detection of a variety of tumours.
Tc-99m-tetrofosmin uptake by
sarcomas in vitro as well as in primary tumours has been reported. Data on the visualisation of metastatic
soft tissue sarcomas using this tracer are missing so far. Ten consecutive patients with histopathologically verified metastatic
soft tissue sarcoma were included in the present study. Five patients had previously received cytotoxic treatment, the other five patients were chemonaive. All patients underwent whole body planar examination after administration of 500-550 MBq
Tc-99m-tetrofosmin, and in case of lung
metastases on CT scan, SPECT images were carried out. Non-physiological accumulation of the tracer was considered as a positive result. Scintigraphic results were compared to conventional imaging by means of MRI/CT scanning. Visualisation of distant
metastases was achieved in five patients all of whom were chemonaive, while in the chemotherapeutically pretreated patient group (n=5) false negative results were seen. Progressive disease was confirmed by follow-up in all patients. Pulmonary
metastases were visualised only in SPECT acquisition and not on planar images. In one patient with diffuse bone marrow infiltration (inflammatory myofibroblastic
sarcoma)
Tc-99m-tetrofosmin scintigraphy was positive, while CT showed a negative result. According to our results, detection of metastatic
soft tissue sarcomas by
Tc-99m-tetrofosmin scintigraphy was strongly dependent on the history of previous treatment of the patient. A positive finding before initiation of
chemotherapy was not indicative for subsequent therapeutic response. In the staging of chemonaive patients with metastatic
soft tissue sarcoma Tc-99m-tetrofosmin may provide some additional information.