Uveal melanoma is the most common cancer that starts inside the eye, arising from pigment-producing cells in the middle layer of the eyeball known as the uvea. It affects roughly five to seven people per million each year in Western countries, making it rare in absolute numbers but significant because of its tendency to spread to the liver, sometimes years after the original eye tumor is treated.1PubMed Central. Uveal melanoma: epidemiology, etiology, and treatment of primary disease Despite sharing a name with skin melanoma, uveal melanoma behaves differently at nearly every level, from its genetic drivers to its response to treatment, and understanding those differences matters for anyone affected by the diagnosis.
Where It Starts and Who Gets It
The uvea is made up of three structures: the iris (the colored part you see), the ciliary body (a ring of tissue behind the iris that focuses the lens), and the choroid (the blood-vessel-rich layer lining the back of the eye). Melanocytes live in all three, and any of them can give rise to uveal melanoma. The vast majority of cases originate in the choroid, with a smaller share in the ciliary body and a still smaller fraction in the iris. Iris melanomas tend to be caught earlier because they are visible in a mirror or during a routine eye exam, and they generally carry a better prognosis than tumors farther back in the eye.
Several personal characteristics are associated with a higher risk. A meta-analysis pooling data from multiple studies found that light eye color roughly doubled the odds of developing uveal melanoma, and fair skin carried a similar increase in risk.2JAMA Ophthalmology. The Association Between Host Susceptibility Factors and Uveal Melanoma: A Meta-analysis A Dutch study refined that picture, showing that green or hazel eyes carried an even stronger association than blue or grey eyes when compared with brown.3PubMed Central. Iris Colour and the Risk of Developing Uveal Melanoma Interestingly, blond or red hair did not emerge as an independent risk factor in the meta-analysis once eye color and skin tone were accounted for.4JAMA Ophthalmology. The Association Between Host Susceptibility Factors and Uveal Melanoma: A Meta-analysis
Ultraviolet light’s role is less clear-cut than for skin melanoma. Occupational outdoor exposure, a history of sunburns to the eyes, and sunlamp use have all been linked to higher risk, and there appears to be an interaction between light iris color and UV exposure.5PubMed. Positive interaction between light iris color and ultraviolet radiation in relation to the risk of uveal melanoma: a case-control study But the relationship is nowhere near as direct as the sun-exposure link in cutaneous melanoma, and many patients have no obvious UV history at all. The upshot is that while wearing UV-blocking sunglasses is sensible, you cannot simply blame sun exposure in most cases.
How It Differs From Skin Melanoma at the Genetic Level
Skin melanoma is commonly driven by mutations in genes called BRAF or NRAS. Uveal melanoma takes a completely different genetic path. Nearly all uveal melanomas carry a mutation in one of two closely related genes, GNAQ or GNA11, which act as the initial spark that pushes the cell toward becoming cancerous.6PubMed Central. GNAQ and GNA11 Genes: A Comprehensive Review on Oncogenesis, Prognosis and Therapeutic Opportunities in Uveal Melanoma About 95% of patients carry one of these mutations, and they are mutually exclusive, meaning a tumor has one or the other, not both.7PubMed Central. Driver mutations in GNAQ and GNA11 genes as potential targets for precision immunotherapy in uveal melanoma patients These mutations lock a signaling switch in the “on” position, prompting the cell to grow when it shouldn’t.
This genetic distinction has practical consequences. Because uveal melanoma lacks BRAF mutations, the targeted therapies that revolutionized skin melanoma treatment (drugs like vemurafenib and dabrafenib) simply do not apply. And as we’ll see, even checkpoint immunotherapies that work well against skin melanoma have limited effectiveness against uveal melanoma, in part because the tumor’s immune landscape is fundamentally different.8PubMed Central. Uveal melanoma: Recent advances in immunotherapy
Telling a Freckle From a Tumor
Many people have a choroidal nevus, essentially a freckle on the back of the eye. These are found in roughly one in ten adults. The overwhelming majority never become cancerous, but a small percentage do transform into melanoma, which makes surveillance important when one is detected. Researchers developed a mnemonic, TFSOM-DIM (“To Find Small Ocular Melanoma Doing Imaging”), to help clinicians remember the features that raise suspicion: tumor thickness over 2 mm, subretinal fluid, symptomatic vision loss, orange pigment (lipofuscin) on the surface, a specific hollow appearance on ultrasound, and a diameter over 5 mm.9PubMed. CHOROIDAL NEVUS IMAGING FEATURES IN 3,806 CASES AND RISK FACTORS FOR TRANSFORMATION INTO MELANOMA IN 2,355 CASES
The risk of a nevus progressing to melanoma scales steeply with the number of these factors present. In a large analysis, having none of the risk factors carried roughly a 1% chance of growth over five years. One factor bumped that to about 11%, two factors to 22%, and having four or more factors pushed the risk above 50%.10PubMed. Understanding choroidal nevus risk factors for transformation into melanoma This graded risk scale helps doctors decide who needs close monitoring every few months versus who can be safely rechecked annually.
Imaging has become central to both detection and follow-up. Fundus photography captures the surface appearance, optical coherence tomography reveals fluid and fine structural changes, and ultrasound measures tumor thickness and internal echogenicity. Combining these modalities gives a more reliable picture than any single test alone.11PubMed Central. Artificial intelligence in the diagnosis of uveal melanoma: advances and applications
Predicting Which Tumors Will Spread
One of the most anxiety-inducing features of uveal melanoma is that roughly half of patients eventually develop metastatic disease, predominantly in the liver.12PubMed Central. Functions and clinical implications of the liver microenvironment in hepatic uveal melanoma metastases Crucially, metastasis often occurs years after the primary eye tumor has been successfully treated, suggesting that tumor cells can escape and lie dormant in the liver for a long time before growing.
Genomic testing of the primary tumor can stratify patients into risk categories with striking accuracy. A gene expression profile test measures 15 genes from a tiny needle biopsy of the eye tumor and assigns it to Class 1 (low metastatic risk) or Class 2 (high metastatic risk). In a prospective multicenter study, Class 1 patients had a three-year metastasis-free survival of 100%, while Class 2 patients had a rate of about 63%.13PubMed Central. Clinical Performance and Management Outcomes with the DecisionDx-UM Gene Expression Profile Test in a Prospective Multicenter Study This test is now widely used and helps guide how aggressively a patient should be screened for liver metastases going forward.14PubMed Central. Gene expression profiling in uveal melanoma: technical reliability and correlation of molecular class with pathologic characteristics
Underneath the gene expression classes, specific mutations tell a more granular story. Loss-of-function mutations in a gene called BAP1 are found in the vast majority of tumors that go on to spread. In one landmark study, BAP1 mutations were present in 84% of metastasizing uveal melanomas.15PubMed Central. Frequent mutation of BAP1 in metastasizing uveal melanomas When BAP1 mutations are combined with loss of one copy of chromosome 3, the statistical association with metastasis becomes very strong.16PubMed. Chromosome 3 status combined with BAP1 and EIF1AX mutation profiles are associated with metastasis in uveal melanoma
On the favorable end, tumors that carry mutations in EIF1AX tend to keep both copies of chromosome 3 and rarely metastasize. SF3B1 mutations occupy a middle ground: they are generally associated with a better prognosis than BAP1 mutations, but patients whose tumors harbor SF3B1 changes are somewhat prone to late metastases, sometimes appearing eight or more years after treatment.17PubMed. Uveal Melanomas with SF3B1 Mutations: A Distinct Subclass Associated with Late-Onset Metastases That late timeline matters clinically because it means surveillance cannot safely stop after just a few clear years.18PubMed Central. Driver Mutations in Uveal Melanoma Associations With Gene Expression Profile and Patient Outcomes
Treating the Eye Tumor
For over a century, the standard treatment for uveal melanoma was enucleation, which means removing the entire eye. That changed after a major trial confirmed in 2001 that radiation-based, eye-sparing treatment produced survival outcomes equivalent to enucleation.19PubMed Central. Brachytherapy for patients with uveal melanoma: historical perspectives and future treatment directions Today, most patients receive one of two forms of radiation.
Plaque brachytherapy is the more common option. A small radioactive disc, typically containing iodine-125 seeds, is sutured onto the outer wall of the eye directly over the tumor. It stays in place for several days, delivering a concentrated dose to the tumor while limiting exposure to the rest of the body. In one 38-year single-institution series of over 1,800 patients, 93% achieved local tumor control with this approach.20Ophthalmology Retina. Long-Term Outcomes of Iodine-125 Episcleral Plaque Brachytherapy for Uveal Melanoma: A 38-Year Single-Institution Experience Recurrence rates at five and ten years were about 12% and 18%, respectively.
Proton beam therapy is an alternative that uses charged particles instead of conventional photon radiation. Protons deposit most of their energy at a precise depth and then stop, which offers an advantage for thicker tumors (over 8 mm) or those sitting near the optic nerve, where conventional radiation risks damaging critical structures.21PubMed Central. Proton Therapy in Uveal Melanoma Reviews of proton therapy data report five-year local control rates above 90%, overall survival rates in the range of 70 to 85%, and enucleation rates consistently between 7 and 10%.22PubMed. Clinical Outcomes of Proton Radiotherapy for Uveal Melanoma The main drawback is that proton beam centers are far less widely available than brachytherapy, which can be performed at most major ophthalmic oncology centers.
Radiation Side Effects and Vision
Saving the eye does not always mean saving the vision. Radiation inevitably affects healthy tissue around the tumor. In the 38-year plaque brachytherapy series, about 42% of patients developed radiation retinopathy and 18% developed radiation-related optic nerve damage.23Ophthalmology Retina. Long-Term Outcomes of Iodine-125 Episcleral Plaque Brachytherapy for Uveal Melanoma: A 38-Year Single-Institution Experience Large tumors carry a particularly high risk: at four years after plaque treatment, roughly 63% of patients with large melanomas had developed swelling in the central retina, compared to about 37% of those with smaller tumors.24PubMed. Impact of uveal melanoma thickness on post-plaque radiotherapy outcomes in the prophylactic anti-vascular endothelial growth factor era in 1131 patients
Age plays an unexpected role. Younger patients actually develop certain radiation complications at higher rates and earlier than older patients, including radiation damage to the macula and non-central retina.25Asia-Pacific Journal of Ophthalmology. Prophylactic Intravitreal Bevacizumab After Plaque Radiotherapy for Uveal Melanoma: Analysis of Visual Acuity, Tumor Response, and Radiation Complications in 1131 Eyes Based on Patient Age The reason is not fully settled, but it may relate to younger tissue being more metabolically active and therefore more susceptible to radiation-induced vascular damage. Despite these complications, the majority of patients treated with proton therapy retained functional vision (better than 20/200), and more recent, high-volume treatment centers report improved numbers.26PubMed. Clinical Outcomes of Proton Radiotherapy for Uveal Melanoma
When It Spreads to the Liver
Uveal melanoma has a peculiar and frustrating affinity for the liver. Unlike skin melanoma, which can spread to the lungs, brain, bones, or virtually anywhere, uveal melanoma metastasizes to the liver first in the overwhelming majority of cases.27PubMed Central. New Insights into the Exosome-Induced Migration of Uveal Melanoma Cells and the Pre-Metastatic Niche Formation in the Liver The mechanisms behind this liver tropism are still being worked out. Recent research has pointed to tiny vesicles (exosomes) released by the tumor that may prepare the liver’s microenvironment to accept incoming cancer cells, essentially laying out a welcome mat before the cells arrive.28PubMed Central. New Insights into the Exosome-Induced Migration of Uveal Melanoma Cells and the Pre-Metastatic Niche Formation in the Liver
Once liver metastases appear, the situation becomes much more difficult to manage. Historically, median survival after detection of liver involvement was measured in months, not years. Several liver-directed approaches have been explored, including radioembolization (injecting radioactive microspheres into the liver’s blood supply), chemoembolization, thermal ablation, and percutaneous hepatic perfusion. A systematic review of these locoregional techniques found a median overall survival of about 16 months and a median progression-free survival of roughly 8 months.29PubMed Central. Percutaneous Locoregional Therapies for the Treatment of Liver Metastases from Uveal Melanoma: A Systematic Review One prospective trial of radioembolization alone reported a median overall survival approaching 19 months.30PubMed Central. A Prospective Phase II Trial of Radioembolization for Treatment of Uveal Melanoma Hepatic Metastasis These numbers represent meaningful extensions compared to untreated disease, but they underscore the severity of metastatic uveal melanoma.
Tebentafusp and the Immunotherapy Landscape
For years, there was no systemic therapy proven to extend life in metastatic uveal melanoma. Standard immune checkpoint inhibitors, the same drugs that dramatically improved outcomes in advanced skin melanoma, show limited benefit against uveal melanoma. The tumor’s low mutational burden means fewer surface markers for the immune system to latch onto, and molecular pathways within the tumor cells can actively exclude cancer-fighting T cells from infiltrating.31Nature Communications. Uveal melanoma immunogenomics predict immunotherapy resistance and susceptibility
Tebentafusp changed the landscape. It is a first-in-class bispecific protein that bridges two things: it recognizes a fragment of a melanoma-associated protein (gp100) displayed on the tumor cell surface, and it simultaneously grabs nearby T cells by their CD3 receptor, pulling them into direct contact with the cancer. It was the first treatment of any kind to show an overall survival benefit in metastatic uveal melanoma in a randomized trial.32PubMed Central. Tebentafusp: a first-in-class treatment for metastatic uveal melanoma At three years, about 27% of patients receiving tebentafusp were alive, compared with 18% in the control group, and median overall survival improved from about 17 months to nearly 22 months.33PubMed Central. Three-Year Overall Survival with Tebentafusp in Metastatic Uveal Melanoma
There is a significant catch: tebentafusp only works in patients who carry a specific immune molecule called HLA-A*02:01, which is present in roughly half of people of European descent and less common in other populations. Patients who are HLA-A*02:01 negative currently have no approved therapy with a proven survival benefit for metastatic disease, which is an active area of research.
Liquid Biopsy and New Surveillance Tools
Because metastases can emerge years after the eye tumor is treated, patients with high-risk tumors undergo regular liver imaging, typically with MRI or ultrasound, for at least a decade. Emerging blood-based tools may improve early detection. Circulating tumor DNA, tiny fragments of cancer DNA shed into the bloodstream, has shown promise in detecting disease progression before it becomes visible on imaging scans.34PubMed Central. Circulating tumor DNA accelerates diagnosis and treatment guidance for metastatic uveal melanoma with hepatic lesions not amenable to biopsy
In patients undergoing liver surgery for uveal melanoma metastases, detectable circulating tumor DNA before the operation was associated with a shorter time before relapse compared with patients whose blood was clear of it.35PubMed Central. Circulating Tumor DNA as a Prognostic Factor in Patients With Resectable Hepatic Metastases of Uveal Melanoma Researchers are also exploring whether combining circulating tumor DNA with other blood markers can flag disease progression earlier in patients receiving immunotherapy.36PubMed Central. Monitoring soluble cMET and ctDNA in metastatic uveal melanoma patients to track early disease progression on immunotherapies These liquid biopsy approaches are not yet part of standard care, but they are moving toward clinical validation and could eventually reduce the reliance on repeated imaging.
Targeted Therapy Research
Because nearly all uveal melanomas are driven by GNAQ or GNA11 mutations, researchers have tried to shut down the signaling cascades those mutations activate. One promising approach targets protein kinase C (PKC), a molecule sitting directly downstream of the mutated proteins. In laboratory studies, a PKC inhibitor called AEB071 (sotrastaurin) selectively halted the growth of uveal melanoma cells carrying GNAQ mutations while leaving cells with other mutations largely unaffected.37PubMed Central. Protein kinase C inhibitor AEB071 targets ocular melanoma harboring GNAQ mutations via effects on the PKC/Erk1/2 and PKC/NF-κB pathways
PKC inhibition alone, however, did not shrink tumors in animal models. The problem turned out to be a rebound: when PKC was blocked, the MAP-kinase signaling pathway found a way to reactivate. Combining a PKC inhibitor with a MEK inhibitor (MEK sits further along the same signaling chain) produced sustained pathway suppression and strong anti-tumor effects, including tumor regression in mouse models, that neither drug achieved on its own.38PubMed Central. Combined PKC and MEK inhibition in uveal melanoma with GNAQ and GNA11 mutations Clinical trials of various combination strategies are ongoing, but as of now none have led to an approved therapy. The field recognizes that single-agent strategies are unlikely to work against a cancer this biologically resilient, and combination approaches remain the most actively pursued direction.
Living With the Diagnosis
Beyond the medical facts, uveal melanoma takes a psychological toll that is often underappreciated. The most commonly reported severe quality-of-life concern is worry about disease recurrence, reported by about 41% of patients even early in the course of care. Vision impairment affected about 81% of surveyed patients, and ocular irritation about 66%.39PubMed Central. Quality of Life Concerns in Patients with Uveal Melanoma after Initial Diagnosis These are not just treatment side effects; they are the daily reality of living with an eye that has been irradiated or removed.
A systematic review of emotional distress among uveal melanoma survivors found that younger age, visual impairment, and pre-existing psychological vulnerability were the strongest predictors of ongoing distress.40PubMed Central. Predictors of emotional distress in uveal melanoma survivors: a systematic review Patients who already felt anxious or distressed at the time of diagnosis were more likely to remain distressed during survivorship, which argues for psychological screening at the point of diagnosis rather than waiting until problems escalate.
The genomic results themselves carry emotional weight. Patients whose tumors are classified as Class 2, or who learn their tumor carries monosomy 3, may show elevated depressive symptoms at every follow-up time point measured over two years compared to those with better-prognosis markers.41Eye. Two-year patient-reported outcomes following treatment of uveal melanoma Younger women tend to report the highest anxiety levels. Encouragingly, overall quality of life for most patients returns to levels comparable to the general population within about six months of treatment, suggesting that adaptation does occur, even if specific worries persist.42Eye. Two-year patient-reported outcomes following treatment of uveal melanoma
Uveal Melanoma in Animals
Uveal melanoma is not exclusively a human disease. Dogs and cats develop melanocytic tumors of the uvea as well, and the patterns differ between species in interesting ways. In dogs, most uveal melanocytic tumors are melanocytomas, which are benign or slow-growing. In cats, the picture is reversed: all five feline cases in one study were classified as melanomas rather than benign growths.43PubMed Central. Canine and feline uveal melanocytic tumours: Histologic and immunohistochemical characteristics of 32 cases Feline uveal melanoma is considered aggressive, and affected cats often require enucleation. The genetics driving these tumors in animals have not been characterized as thoroughly as in humans, but comparative oncology research is ongoing, and the differences between dogs and cats may eventually shed light on what makes certain melanocytic cells more prone to malignancy than others.