Positron emission tomography in patients with aggressive fibromatosis/desmoid tumours undergoing therapy with imatinib.

PURPOSE

We used (18)F-FDG PET to evaluate the FDG uptake in patients with aggressive fibromatosis (AF, also known as desmoid tumours) undergoing therapy with imatinib (imatinib mesylate, Glivec).

METHODS

The pilot study included nine patients with progressive AF receiving oral treatment with imatinib at a daily dose of 800 mg. Patients were examined using PET prior to the start of therapy and during imatinib treatment. Restaging according to the Response Evaluation Criteria in Solid Tumors (RECIST) was performed in parallel using CT and/or MRI and served as reference.

RESULTS

The clinical outcomes in nine evaluable patients were as follows: seven patients with stable disease, and two patients with progressive disease. A 27% decrease in the median average standardized uptake value (SUV) of the sequential PET examinations was demonstrated in all evaluable patients with three patients (33%) showing a decrease in SUV of more than 40% (48%, 52% and 54%, respectively); no patient showed a substantial increase in SUV.

CONCLUSION

To our knowledge, this is the first series of AF patients undergoing treatment with imatinib and monitored using sequential PET imaging, that allows detection of SUV changes after imatinib induction, thus helping to decide whether treatment should be continued or not.