The impact of 18F-FDG PET-CT scanning for staging and management of Merkel cell carcinoma: Results from Westmead Hospital, Sydney, Australia

Background: Merkel cell carcinoma (MCC) is a rare cutaneous malignancy with high mortality. Positron emission tomography (PET) using F-18-fluorodeoxyglucose (FDG) has been shown to be valuable in the management of many types of cancer, and the purpose of this work was to determine its utility for patients with MCC. Objective: We sought to evaluate the impact of F-18-FDG PET with simultaneous computed tomography (PET-CT) on the staging and management of patients with MCC. Methods: We reviewed the medical records of 18 patients with MCC who underwent 21 PET-CT scans at our institution from 2006 to 2008. The impact of PET-CT on staging and management plans were evaluated. Results: There were 12 men and 6 women with median age of 79 years (range, 54 to 87 years). All proven sites of MCC greater than 5 mm were positive on PET-CT with average maximum standardized uptake values (SUV max) of 4 in primary lesions. 5.6 in nodal disease and 11.5 in distant metastases. PET-CT contributed to altered staging in 7 patients (33%) and a change in management in 9 patients (43%). Two patients were found to have a second primary malignancy, but this did not alter management. Limitations: This was a retrospective review. Most patients had stage II or III disease, suggesting some potential referral bias. Conclusions: F-18-FDG PET-CT had a high impact in the management of MCC patients in our series and this investigation merits further assessment. (J Am Acad Dermatol 2010;62:76-84.)