Surveillance for Metastasis in Low-Risk Uveal Melanoma Patients: The Need for Optimization.

Abstract

To evaluate the effectiveness of surveillance protocols using hepatic ultrasonography (US) at 6-month intervals to detect metastasis and determine its impact on overall survival (OS) in patients with low-risk uveal melanoma (UM). Retrospective cohort study. A total of 144 consecutive patients with class 1 (low risk) primary UM were enrolled. All patients had negative baseline systemic staging, after which they underwent systemic surveillance with hepatic US at 6-month intervals: standard protocol (SP) or enhanced protocol (EP) using high frequency (US every 3 months) or enhanced modality (EM) (hepatic computed tomography/magnetic resonance imaging). Largest diameter of largest hepatic metastasis (LDLM), number of hepatic metastatic lesions, time to detection of metastasis (TDM), and OS. Median follow-up time for those still alive (134 [10 patients died of any cause]) was 50.6 months (interquartile range [IQR], 28.6-76.1). Surveillance was done with SP in the majority (101 [70%]) and EP in 43 (30%). A total of 834 US scans were obtained (median 5.0 [IQR, 3.0-8.0]) that led to the detection of metastasis in 6 patients by SP in the majority (5 of 6) and EP in 1 of 6. The median LDLM at detection was 2.8 cm. Only tumor largest basal diameter was significantly associated with increased hazard of metastasis (hazard ratio, 1.33 [95% confidence interval, 1.04-1.70]; P =  0.022), whereas age, tumor thickness, and PReferentially expressed Antigen in Melanoma (PRAME) status were not. All patients were treated for metastasis (liver directed 1 [17%], systemic therapy 5 [83%]). The vast majority of patients with UM predicted to have a low risk of metastasis do not develop metastasis by 5 years (96%). Surveillance protocols in such patients have very low yield, and their impact on survival cannot be assessed. Our study demonstrates the need for further risk refinement of patients with low-risk UM to better identify at-risk individuals. Currently used surveillance protocols need to be optimized. Proprietary or commercial disclosure may be found after the references.