The diagnosis of metastatic uveal melanoma. What has changed during 10 years?

Abstract

Uveal melanoma is the most common intraocular malignancy. Despite significant progress in the treatment of the primary tumor, uveal melanoma continues to be the most aggressive tumor due to its high potential for hematogenous metastatic spread. Uveal melanoma metastases are located mostly in the liver. Overall survival of patients with liver metastases is 4 to 15 months. There is no adjuvant systemic therapy to prevent metastases of uveal melanoma. In this paper, we aim to analyze achievement in diagnosis of metastatic uveal melanoma made during the last 10 years and to show advantages and disadvantages of the main diagnostic methods. The last years showed the emergence of understanding the differences between skin and uveal melanoma based on different molecular genetic abnormalities and different signaling pathways of these tumors. The success of target treatments for skin melanoma is not applicable to uveal melanoma. Skin and uveal melanoma responds differently to immune checkpoint inhibitors. Insufficient efficacy of systemic chemotherapy, immune and target therapy has made it necessary to develop techniques of local chemoembolization and radioembolization of uveal melanoma metastases. At present, there are no available assessment algorithms for the management of patients with uveal melanoma and suspected metastases. Ultrasonography, if seen as available techniques for radiology diagnostics, should be enhanced either by the intravenous contrast, or by qualifying computed tomography. The use of positron emission tomography / computed tomography has not demonstrated the maximal diagnostic value in identification of liver metastases, and, taken into account its high costs, low availability, and large radiation dose, it cannot be considered as a feasible method for every 6 months' application. The most effective diagnostic method is magnetic resonance imaging with the liver-specific contrast agents, due to the possibility to detect metastases of less than 1 cm in diameter. However, this technique has not been widely accepted clinically due to high costs, contraindications and a big proportion of false positive results. Current armamentarium of radiation techniques that could be potentially applicable for visualization of hepatic focal abnormalities is rather impressive and is being continuously updated; however, the problem of the metastatic uveal melanoma diagnosis remains unsolved.