18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Imaging in the Management of Merkel Cell Carcinoma: A Single-Institution Retrospective Study

Department of Dermatology, University of Rochester Medical Center, Rochester, New York.
Dermatologic Surgery (Impact Factor: 2.11). 06/2013; 39(9). DOI: 10.1111/dsu.12246
Source: PubMed


BACKGROUND: Merkel cell carcinoma (MCC) is among the deadliest of cutaneous malignancies. A lack of consensus evaluation and treatment guidelines has hindered management of this disease. The utility of simultaneous positron emission tomography and computed tomography (PET/CT) has been demonstrated for a variety of tumors yet remains underinvestigated for MCC. OBJECTIVES: To report the value of fluorodeoxyglucose PET/CT imaging in the initial staging and ongoing management of individuals with MCC and to determine whether any patient or tumor characteristics may predict when PET/CT is more likely to have greater influence on medical decision-making. MATERIALS AND METHODS: A single-institution retrospective chart review was conducted of all patients diagnosed with MCC who underwent FDG-PET/CT scanning from 2007 to 2010. The outcome of each of these studies was evaluated as to the influence on patient staging and management. Patient clinical information and information on gross and microscopic tumor characteristics were collected and analyzed. RESULTS: Twenty patients underwent 39 PET/CT scans. Results of PET/CT imaging revealed previously unknown information related to MCC in four (20%) patients, leading to changes in management in three of these four cases. Three previously unknown neoplasms were detected. CONCLUSION: Fluorodeoxyglucose-positron emission tomography and computed tomography is a valuable tool for initial staging and to assess response to therapy of patients diagnosed with MCC. Larger prospective studies would be required to establish the optimal timing for this imaging modality.

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    ABSTRACT: Some studies reported the usefulness of fluorine-18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and PET/computed tomography (CT) in patients with Merkel cell carcinoma (MCC). The aim of this study was to systematically review and meta-analyze published data about the diagnostic performance of (18)F-FDG PET and PET/CT in patients with MCC. A comprehensive literature search of studies published through June 2013 regarding (18)F-FDG PET and PET/CT in patients with MCC was performed. All retrieved studies were reviewed and qualitatively analyzed. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR+ and LR-) and diagnostic odds ratio (DOR) of (18)F-FDG PET or PET/CT in patients with MCC on a per examination-based analysis were calculated. The area under the summary receiver operating characteristic (ROC) curve was calculated to measure the accuracy of (18)F-FDG PET or PET/CT in these patients. Ten studies comprising 329 patients (549 scans) with MCC were included in the qualitative analysis (systematic review) and discussed. The quantitative analysis (meta-analysis) of six selected studies (including 92 patients with MCC) provided the following results on a per examination-based analysis: sensitivity was 90 % (95 % CI 80-96), specificity 98 % (95 % CI 90-100), LR+ 12 (95 % CI 4.3-33.0), LR- 0.15 (95 % CI 0.08-0.28), and DOR 86.8 (95 % CI 23-327). The area under the summary ROC curve was 0.96. No significant statistical heterogeneity between the studies was found. In patients with MCC, (18)F-FDG PET or PET/CT demonstrated high sensitivity and specificity, being accurate methods in this setting. Nevertheless, the literature focusing on the use of PET and PET/CT in MCC still remains limited. Prospective studies are needed to substantiate the high diagnostic accuracy of these methods in MCC.
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    ABSTRACT: Several molecular imaging modalities have been evaluated in the management of Merkel cell carcinoma (MCC), a rare and aggressive tumor with a high tendency to metastasize. Continuous progress in the field of molecular imaging might improve management in these patients. The authors review the current modalities and their impact on MCC in this brief review article.
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