Screening for metastasis from choroidal melanoma: the Collaborative Ocular Melanoma Study Group Report 23

To describe the predictive value of liver function tests (LFTs), chest x-ray, and diagnostic imaging for detecting melanoma metastasis during routine follow-up after treatment for choroidal melanoma.

Prospective longitudinal follow-up of patients enrolled onto two randomized trials was conducted by the Collaborative Ocular Melanoma Study (COMS) Group. Baseline and annual or semiannual systemic and laboratory evaluations were performed according to a standard protocol for 2320 patients enrolled on the COMS.

COMS patients were screened annually for metastasis and new cancers using LFTs (alkaline phosphatase, AST, ALT, or bilirubin). Elevated findings (1.5 to 2 times upper limit of normal) on LFT prompted a diagnostic or imaging test to confirm or rule out cancer recurrence. Of 714 patients with clinical reports of metastasis, 675 patients died. Of these 675 patients, all but four had either histopathologically confirmed or clinically suspected metastatic melanoma present at the time of death. Among all patients, the 5-year cumulative diagnosis rate of metastatic melanoma was 24% (95% CI, 22% to 27%). Based on all patients with reported metastasis, the sensitivity, specificity, positive predictive value and negative predictive value associated with at least one abnormal LFT before first diagnosis of metastasis at any site was 14.7%, 92.3%, 45.7% and 71.0%, respectively.

Use of LFTs results followed by diagnostic tests has high specificity and predictive values but low sensitivity. Better tests are needed to identify earlier metastatic disease associated with choroidal melanoma.