Initial PET/CT staging for choroidal melanoma: AJCC correlation and second nonocular primaries in 333 patients

To report on whole body positron emission tomography/computed tomography (PET/CT) screening for metastasis at diagnosis of primary uveal melanoma.

Since August 2003, 333 consecutive patients were diagnosed with uveal melanoma and underwent whole body screening for metastatic disease with PET/CT along with liver function tests and physical examination. Abnormal findings prompted further biopsies, blood tests, imaging, or clinical evaluations for confirmation. The presence of metastatic disease and second cancers were evaluated.

Using the American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) 7th edition criteria, 104 tumors were classified T1 (31%), 162 T2 (49%), 37 T3 (11%), and 30 T4 (9%). Seven of 333 (2.1%; 95% confidence interval [CI] 0.8-4.3) patients had metastatic melanoma. One tumor was a T3 and 6 were T4. Thus, 3% of T3 and 20% of T4 melanomas were found to have metastases at the time of initial diagnosis. Ten patients (3.3%; 95% CI 0.9-5.5) had synchronous second cancers and 28 (8.4%) concurrent benign lesions. The most common metastatic sites were liver (7/7) and bone (2/7).

This study suggests that PET/CT improves the yield of detecting both extrahepatic metastases, especially from tumors defined as AJCC-T4, and synchronous primary cancers, irrespective of the size of the uveal melanoma. With respect to liver metastases, PET/CT demonstrated high sensitivity and positive predictive values, indicating an overall better performance than conventional screening procedures.