Abstract
Purpose: :
To investigate the value of whole body PET/CT as a screening tool for patients with suspected uveal metastasis.
Methods: :
A retrospective chart review was conducted of fourteen patients with clinically diagnosed intraocular metastatic tumors. Patients either had no history of malignancy or a past history of systemic malignancy without known metastatic disease. Each patient underwent whole body 18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) utilized as a screening tool to evaluate the intraocular tumor, define the primary or to discover multi-organ metastatic disease.
Results: :
Fourteen patients [mean age of 58 (range 41-85)] diagnosed with intraocular metastatic tumors were screened with PET/CT. Eight patients (57%) had no known history of malignancy. Six (43%) had a history of cancer thought to be in remission or metastasis thought to have been localized to an isolated lesion. There were 13 unifocal posterior choroidal tumors (one with extrascleral extension), and one unifocal anterior uveal metastasis. PET/CT imaging revealed widespread metastasis (involving 2 or more metastatic foci) in 13 of 14 (93%) patients. The remaining PET/CT revealed the primary tumor (breast), the intraocular metastasis, but no other metastatic lesions. The most common metastatic lesions detected on PET/CT were osseous (n=8/14, 57%). Lung lesions were the second most common (n=7/14, 50%). The intraocular tumors were detected on PET/CT in 5/14, 36% of cases. Brain metastases were detected on PET/CT in 2 cases, both of which were confirmed by magnetic resonance imaging (MRI). False negative PET/CT findings were seen in two cases: one had brain metastasis detected by MRI, the other a prostate cancer diagnosed to be the primary source only after biopsy of a distant metastasis. Biopsy was used to confirm the primary tumor in 79% (n=11/14) of patients. Forty-two percent were found to have metastatic lung carcinoma, 29% metastatic breast carcinoma and the other 29% had colon, esophageal, prostate and pancreatic carcinomas.
Conclusions: :
PET/CT was found useful in evaluation of patients with suspected uveal metastases. It allowed for screening of the entire body, directed extraocular biopsy and tumor staging. Small, non-avid tumors and those within the hypermetabolic brain can be missed. However, in most cases, PET/CT revealed diffuse metastatic disease. This study suggests that PET/CT was helpful in the evaluation of patients referred for evaluation of uveal metastasis.