Though innumerable scientific articles start with “the most common intraocular malignancy is choroidal melanoma,” choroidal metastases are much more common.1 Uveal metastases are seen histologically at postmortem in up to 12.6% of patients dying from metastatic cancer.2 However, clinically observable metastatic disease has been noted in only 2%–7% of patients with dissem-inated disease.3-5 Similarly, orbital metastases have been found in up to 5% of patients with systemic malignancy.6,7 This disparity is likely due to the patients being asymptomatic, having little time to live, or a combination of both.5,8 Further, systemic treatment may render the ocular metastasis occult, leaving the patient and oncologist unaware of its existence. , However, the life expectancy for patients with metastatic disease from cancers that commonly spread to the eye has improved over time, particularly in the case of breast cancer.9,10 This longevity has resulted in increased numbers of patients needing ocular treatment to prevent vision loss and ensure their quality of life.11,12 Further, ocular metastases may be the first presentation of systemic disease. One study found that uveal metastases from lung carcinoma (47%), pancreatic cancer (37%), and lung carcinoid (33%) often preceded the systemic diagnosis; by contrast, 94% of patients with breast metastases had a history of the disease.13 Other studies have reported similar results.9,14,15 Similarly, 15% of patients with orbital metastases do not have a cancer diagnosis at presentation.7 Some ocular metastases may, albeit rarely, occur after a tumor has been in remission for years (reported up to 43 years later), which may be a diagnostic shock.16-18 The ocular presentation of metastatic disease is also changing. For instance, because the eye is a relatively immunologically privileged site, vitreous metastases of cutaneous melanoma (Fig. 35-1) are increasingly common in patients on checkpoint inhibitors and who are otherwise in remission.19,20 Prior to this therapy, vitreous involvement was seen only in 18% of eye, lid, or orbital cutaneous melanoma metastases.21 , Further, there has been an evolution of local therapies. The goal of local treatment is to retain vision. Thus, observation for response to systemic therapy may work but risks vision loss in cases where the reattachment of the macula is delayed. Treatments to decrease exudative retinal detachments include laser (e.g., PDT), intravitreal anti-VEGF injections, and steroid implants.22 Larger tumors may be treated with EBRT and smaller extramacular tumors with plaque brachytherapy. However, both forms of radiation carry dose-dependent risks of long-term side effects in longer-lived patients.23 Finger has used anti-VEGF drugs as a bridge therapy to more definitive EBRT irradiation.
Chapter Keyword: immunotherapy
Systemic Treatment of Uveal Melanoma: Insights and Emerging Strategies
Uveal melanoma (UM) is a relatively rare cancer, but is the most common primary intraocular malignancy (see Chapter 25) and comprises 5% of all melanoma diagnoses in the United States.1,2 UM arises from mel¬anocytes within the capillary-rich uveal tract, with the most frequent locations being the choroid (90%), ciliary body (6%), and iris (4%).3 Although UM occurs with an incidence of ~2,000 cases per year, it is an aggressive can¬cer.4,5 Screening with periodic, abdominal radiographic imaging, 25%–30% of patients are diagnosed with met¬astatic UM within 5 years (see Chapter 27). Exiting the eye by hematogenous spread, commonly reported met¬astatic sites include the liver (89%), lung (29%), and bone (17%).6 The latency between the treatment of the primary tumor and the emergence of metastases ranges from months to decades, underscoring the likelihood of early dissemination from the primary site and varia¬ble metastatic growth rates.7 Unfortunately, there is no standardized consensus and known effective treatment for advanced UM in the adjuvant or metastatic settings. The prognosis is poor once metastasis develops, with a median overall survival of 10.2 months.8 Long-term sur-vival is unusual except in rare patients with isolated liver metastases amenable to surgical resection. When availa¬ble and clinically appropriate, treatment within a clinical trial is recommended.
Although UM differs from cutaneous melanoma both clinically and biologically, treatment options for advanced stages have largely been adopted with much lower resultant response rates.9 Similarly, in that UM metastases are less responsive than cutaneous melanoma to both chemotherapy and immune checkpoint inhibi¬tors, several treatment modalities have been evaluated, including systemic chemotherapy, immunotherapy, and molecularly targeted agents for the MAPK pathway. As the most common initial site of metastasis is the liver, palliative management includes liver-directed thera¬pies such as bland embolization, chemoembolization, radioembolization, immunoembolization, and hepatic arterial infusion of chemotherapy. In this chapter, we review the molecular pathogenesis of UM, its progno¬sis, and advances in the management of metastatic UM (Mind map 14-1).