Abstract
Purpose: :
To report our findings of 3 synchronous primary cancers and 2 metachronous primary cancers revealed through whole–body 18–fluoro–2–deoxyglucose positron emission tomography/computed radiographic tomography (FDG–PET/CT) imaging during metastatic surveys for patients with uveal melanoma.
Methods: :
One hundred thirty–nine patients with uveal melanoma were evaluated by whole body FDG–PET/CT tumor–staging at the time of initial diagnosis (n=93) and at follow–up evaluation (after treatment with plaque brachytherapy or enucleation, n=46). Intravenous 18–fluoro–2–deoxyglucose PET scan images were obtained and fused with whole–body CT during the same diagnostic session. PET images revealed abnormal FDG uptake within the second primary cancer locations while CT allowed for anatomic correlation.
Results: :
Five patients (3.6%) with uveal melanoma had second primary cancers revealed by whole–body FDG–PET/CT imaging during their metastatic work–up. Three were synchronous (1 lung primary, 1 breast primary, 1 thyroid adenoma with atypical features) in that they were revealed at initial staging (within 6 months of the diagnosis) and 2 were metachronous (1 lung primary, 1 recurrent primary uterine) since they were discovered more than 6 months after diagnosis. In two of the patients with synchronous primary cancers (lung and breast), standard evaluations (CT chest alone, mammogram) did not detect these primaries within 6 months of the FDG–PET/CT. In the patients with metachronous primary cancers, initial staging (CXR, LFTs, abdominal CT) was performed prior to 103Pd plaque radiotherapy and was negative for other cancers. The metachronous lung primary and the recurrent primary uterine cancers were revealed 27 and 19 months following treatment, respectively. In all cases, the second primary cancers were confirmed by biopsy.
Conclusions: :
In this series, whole–body FDG–PET/CT imaging revealed second (synchronous or metachronous) primary cancers in 3.6% of patients with uveal melanoma. Though whole–body FDG–PET/CT scans were ordered to detect early metastatic uveal melanoma, synchronous or metachronous second primary cancers were found.
Keywords: melanoma • imaging/image analysis: clinical • tumors