Impact of 18F-Fluorodeoxyglucose Positron Emission Tomography Before and After Definitive Radiation Therapy in Patients With Apparently Solitary Plasmacytoma
Received 17 June 2008; received in revised form 21 August 2008; accepted 21 August 2008. published online 26 November 2008.
Purpose
To evaluate the impact of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) on management of patients with apparently isolated plasmacytoma.
Methods and Materials
Twenty-one patients with apparently solitary plasmacytoma who underwent FDG-PET for staging or restaging were identified from a central PET database. They were either candidates for or had received definitive radiation therapy (RT).
Results
Seventeen patients had initial staging scans for bone (n = 11) or soft tissue (n = 6) plasmacytomas, and 11 had PET scans after RT. Only 1 of 14 known untreated sites of plasmacytoma was not identified on staging PET (lesion sensitivity = 93%). Three plasmacytomas were excised before PET. Staging PET influenced management in 6 of 17 patients (35%) by showing multiple myeloma (n = 1), discouraging RT after complete resection (n = 1), excluding plasmacytoma at a second site (n = 1), by increasing RT fields (n = 2), or by suggesting sarcoidosis (n = 1). Fifteen of 17 patients with initial staging PET scans received definitive RT. Restaging PET scans after RT showed complete metabolic response in 8 of 11 cases and progressive disease in 2. Two patients with either no response or partial metabolic response had late responses. Staging sestamibi and PET scans were concordant in five of six occasions (one sestamibi scan was false negative).
Conclusions
FDG-PET has value for staging and RT planning in plasmacytoma and potentially could have a role in response-assessment after RT. Slow resolution of FDG uptake posttreatment does not necessarily imply an adverse prognosis.
∗Department of Radiation Oncology, California Pacific Medical Center, San Francisco, CA
†Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
‡Centre for Molecular Imaging and Translational Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
§Department of Haematology/Medical Oncology, Peter MacCallum Cancer Centre, and University of Melbourne, Melbourne, Victoria, Australia
Reprint requests to: Michael P. Mac Manus, M.D., FRANZCR, Department of Radiation Oncology, Peter MacCallum Cancer Centre, St. Andrew's Place, East Melbourne, Victoria 3002, Australia. Tel: (+613) 9656-1111; Fax: (+613) 9656-1424
ABSTRACT