Original article
Positron emission tomography/computed tomography imaging in Merkel cell carcinoma: A study of 270 scans in 97 patients at the Dana-Farber/Brigham and Women's Cancer Center

This work was presented at the 70th Annual American Academy of Dermatology Meeting, San Diego, California, March 16-20, 2012, and as a poster at the 48th Annual American Society of Clinical Oncology (ASCO) Meeting, Chicago, Illinois, June 1-5, 2012.
https://doi.org/10.1016/j.jaad.2012.08.042Get rights and content

Background

Merkel cell carcinoma (MCC) is a rare and lethal cutaneous neuroendocrine carcinoma. Imaging is crucial for accurate staging, which remains a strong predictor of survival, as well as earlier detection of recurrence and progression, which are common despite aggressive management. There is no consensus on the role of initial and subsequent imaging for MCC.

Objective

We sought to evaluate the use of 2-fluoro-[18F]-deoxy-2-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in the management of MCC.

Methods

In all, 270 FDG-PET/CT studies were performed in 97 patients with pathology-proven MCC at the Dana-Farber/Brigham and Women's Cancer Center, Boston, Mass, from August 2003 to December 2010.

Results

FDG-PET/CT scans were obtained as part of the initial (61 scans in 61 patients) and subsequent (209 scans in 79 patients) treatment strategies. MCCs were FDG-avid with a mean maximum standardized uptake value of primary lesions of 6.5 (range 1.3-12.9) and a mean maximum standardized uptake value of regional and distant metastases of 7.2 (range 1.5-9.9). FDG-PET/CT upstaged 16% of patients who underwent baseline scans. FDG-PET/CT studies showed that bone and bone-marrow metastases were more common than previously reported, and were often undetected by CT.

Limitations

Our study is limited by its retrospective design, and potential referral bias associated with a tertiary care center.

Conclusions

FDG-PET/CT performed as part of the initial management strategy tended to upstage patients with more advanced disease. FDG-PET/CT performed as part of the subsequent treatment strategy identified metastatic disease, particularly in bone/bone marrow, which was not seen on CT. FDG-PET/CT imaging is a valuable staging and restaging tool in MCC management.

Section snippets

Methods

This study was approved by the institutional review board at DF/BWCC. From our patient database, we identified patients with a histologic diagnosis of MCC who underwent FDG-PET or PET/CT imaging at DF/BWCC between August 2003 and December 2010. Clinical data were extracted from the electronic medical record. Patients were staged according to the AJCC guidelines: primary tumor 2 cm or smaller without regional lymph node metastasis by histologic (stage IA) or clinical (stage IB) examination;

Results

In all, 97 patients underwent 270 FDG-PET/CT studies at the DF/BWCC from August 2003 to December 2010. The mean age at diagnosis was 70 years (range 44-91). There were 56 men (58%) and 41 women (42%). A total of 94 patients were white and 3 patients were from Central America. Nine patients (9%) were immunosuppressed. Primary lesions were most commonly located on the head and neck (37/97, 38%) followed by near equal distribution on the upper (23/97, 24%) and lower (22/97, 23%) extremities,

Discussion

To our knowledge, this study represents the largest series of patients with MCC evaluated by FDG-PET/CT imaging. In keeping with the literature, our patients were older (mean age 70 years), predominantly white (97%), with a slight male preponderance (1.4:1). In contrast to previous larger studies,24, 25 primary tumors in our study were mainly located on the ultraviolet-exposed skin of the extremities (47%) followed by the head and neck (38%)3 (Table I). Given the anatomic distributions,

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  • Cited by (0)

    Dr O'Regan is currently affiliated with the Department of Radiology, Cork University Hospital, Cork, Ireland; Dr Sheehy is currently affiliated with Department of Radiology, St James's Hospital, Dublin, Ireland; and Dr Wang is currently affiliated with the Institute for Cancer Care at Mercy Medical Center, Baltimore, Maryland.

    Funding sources: None.

    Conflicts of interest: None declared.

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