Choroidal Metastases

Haematogenous deposits of systemic cancer in the choroid, the commonest intraocular malignancy in adults, reflecting the high blood flow to the posterior choroid. Found in up to 10 to 12 percent of patients with advanced cancer at autopsy.

• Primary sites: breast carcinoma (about 40 percent in women), lung carcinoma (about 25 percent; commonest in men, often presenting with the eye lesion before the primary is found), gastrointestinal tract, kidney, prostate, skin melanoma, thyroid, and other cancers; in about 15 to 20 percent the primary is unknown at presentation.
• Bilateral in 20 to 30 percent and multifocal in many; usually in the posterior pole and temporal fundus.
• Usually occurs in the setting of widespread metastatic disease (liver, bone, brain), and the eye can be the first sign of systemic malignancy.
• Risk factors for ocular spread: breast and lung primaries, advanced disease, and cerebral metastases.

• Blurred vision, visual field loss, metamorphopsia, floaters, photopsia, and pain (with raised intraocular pressure or inflammation); about 20 to 30 percent are asymptomatic.
• Fundus: flat or slightly elevated creamy white to yellow subretinal mass with an irregular surface, mottled pigment ("leopard spots") and exudative retinal detachment that is disproportionately large for the tumour size; lesions are often multiple or bilateral.
• Dome shaped or mushroom shaped (rare) in some; breast metastases are often flat and diffuse; melanoma and carcinoid are brown or pink.
• Associated findings: choroidal folds, retinal pigment epithelial detachment, vitreous cells, and secondary glaucoma with iris involvement; may affect the optic disc.
• Rapid growth over weeks, with visual loss, is typical.

• Dilated fundus examination, fundus photographs, and widefield imaging.
• B-scan ultrasound: dome or plateau shaped mass with medium to high internal reflectivity (irregular), subretinal fluid; thickness usually under 5 mm. Optical coherence tomography with enhanced depth imaging (lumpy anterior surface, "lumpy bumpy", subretinal fluid, shaggy photoreceptors); fundus autofluorescence (leopard spot pattern); fluorescein angiography (early hypofluorescence, late staining) and indocyanine green angiography.
• Systemic workup: history of cancer, physical examination, CT or PET-CT of chest, abdomen and pelvis, brain MRI, tumour markers, and bone scan; where the primary is unknown, biopsy (fine needle aspiration or a biopsy of an accessible site) with immunohistochemistry (cytokeratin, TTF-1, oestrogen and progesterone receptors, PSA, PAX8, melanoma markers).
• Differentiate from choroidal melanoma (isolated, dark, collar stud, acoustic hollowness) and other tumours.

• Multidisciplinary care with oncology; treatment aims at palliation, quality of life, and preservation of vision, and depends on symptoms, tumour size, systemic disease control, and life expectancy.
• Asymptomatic small tumours and tumours responding to systemic therapy (chemotherapy, hormonal therapy, targeted therapy, immunotherapy) can be observed with review every 4 to 8 weeks. Oestrogen receptor positive breast cancer: aromatase inhibitors (anastrozole 1 mg daily, letrozole 2.5 mg daily) or tamoxifen 20 mg daily, with CDK4/6 inhibitors added to an aromatase inhibitor or fulvestrant in advanced disease; HER2-positive disease: trastuzumab; lung cancer with EGFR mutation: osimertinib 80 mg daily; ALK-rearranged: alectinib 600 mg twice daily; other targeted and immune checkpoint therapies according to the primary.
• Radiotherapy for symptomatic, progressive or sight threatening lesions:
  • External beam radiotherapy: 30 to 40 Gy in 10 to 20 fractions (commonly 30 Gy in 10 fractions or 40 Gy in 20 fractions) gives tumour control in 85 to 95 percent and improves vision in 50 to 70 percent.
  • Plaque brachytherapy (iodine-125 or ruthenium-106, apex dose 40 to 70 Gy), proton beam therapy, or stereotactic radiosurgery for solitary or large lesions and previously irradiated eyes.
  • Photodynamic therapy with verteporfin (6 mg/m2) and transpupillary thermotherapy for small or radioresistant tumours; intravitreal anti-VEGF (bevacizumab 1.25 mg) for associated neovascular and exudative components.
• Enucleation only for painful blind eyes with neovascular glaucoma or extensive tumour with no useful vision.
• Radiation complications: cataract, dry eye, radiation retinopathy and optic neuropathy (monitor and treat with intravitreal anti-VEGF).
• Prognosis is determined by the primary and the extent of systemic disease: median survival is about 7 to 12 months for lung cancer, 1 to 2 years for breast cancer, and varies for other tumours; local therapy provides durable local control.
• Follow up every 1 to 3 months initially with examination, ultrasound, and optical coherence tomography.