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

Abstract

Purpose: To evaluate the effectiveness of surveillance protocols utilizing hepatic ultrasonography (US) at 6-month intervals to detect metastasis and determine its impact on overall survival (OS) in low-risk uveal melanoma (UM) patients.

Design: Retrospective Cohort Study SUBJECTS: 144 consecutive patients with Class 1 (low risk) primary UM were enrolled.

Methods: All patients had negative baseline systemic staging following which they underwent systemic surveillance either with hepatic US at 6-month intervals (standard protocol, SP) or enhanced protocol (EP) utilizing high frequency (US every 3 months) or enhanced modality (EM, hepatic computed tomography/magnetic resonance imaging).

Main outcome measures: Largest diameter of largest hepatic metastasis (LDLM), number of hepatic metastatic lesions, time to detection of metastasis (TDM), and OS.

Results: Median follow-up time for those still alive (134, 10 patients died from any cause) was 50.6 months (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 performed (median 5.0 [IQR: 3.0, 8.0])) that led to detection of metastasis in 6 patients by SP in the majority (5/6) and EP in 1/6. The median LDLM at detection was 2.8 cm. Only tumor largest basal diameter was significantly associated with increased hazard of metastasis (HR 1.33 [95% CI, 1.04-1.70]; p= 0.022) whereas age, tumor thickness, and PRAME status were not. All patients were treated for metastasis (liver directed 1 [17%], systemic therapy 5 [83%]).

Conclusions: The vast majority of patients with UM predicted to have 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 low-risk UM patients to better identify at-risk individuals. Currently used surveillance protocols need to be optimized.