¹⁸F-Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET): An Important Tool in the Management of Infection in Patients with Hematological Cancer.

Background: FDG-PET is useful for detecting cancer (ca) sites and preliminary data suggest a role in bone and joint infection, mostly in non-immunosuppressed hosts.

Purpose: To determine the role of FDG-PET in the management of infection in patients (pts) with hematological ca.

Patients and Methods: Between 10/01/2001 and 5/31/2004, FDG-PET scans performed for ca staging and /or for the diagnosis of suspected infection that were reported as showing increased radiotracer uptake at extramedullary sites were reviewed. Results of FDG-PET were correlated with clinical and laboratory findings to identify episodes of infection.

Results: 184 infections were documented by FDG-PET in 164 pts (90% multiple myeloma). Median age was 58 years (range 25–79) and 108 pts were males. 59 pts were neutropenic (<1000 neutrophils/ml) and 32 had severe immunosuppression (neutrophils, lymphocytes and / or CD4 counts <100 cells/ml).FDG-PET identified respiratory tract infections (118; including pneumonia/empyema, 112 and sinusitis, 6), vascular infections (27; septic thrombophlebitis (STP), 16 and infection of implantable catheter, 11), discitis / osteomyelitis (19), gastrointestinal tract infections (10; colitis, 5; diverticulitis and abdominal abscess (2 each) and esophagitis, 1), periodontal abscesses (10), cellulitis (2) and mastoiditis (1). 59 infections were microbiologically documented including bacterial (42), fungal (13), viral and mycobacterial (2 each). FDG-PET detected infectious foci despite severe immunosuppression (32 episodes). FDG-PET contributed to pt management including identification of the presence and site of infection (77), determination of its extent (81), modification of the diagnostic work-up and /or therapy (71) and evaluation of response (79). 58 clinically silent infections were detected among pts undergoing FDG-PET for ca staging.

Conclusion: In pts with hematological ca, FDG-PET is a useful tool for establishing the presence, site (s), and extent of infection with various pathogens and in various organs, even in the setting of severe immunosuppression. FDG-PET can identify clinically silent infections and infections not detectable by other methods (such as STP) and can result in significant changes in pt management.