Paraneoplastic retinopathy, treatment effects and counselling
Key Takeaways
Paraneoplastic visual loss can precede a known malignancy and occur without visible ocular metastases.
CAR antibodies and MAR ERG patterns support a clinical diagnosis but are not individually definitive.
BDUMP is a bilateral paraneoplastic uveal process requiring systemic malignancy assessment.
Cancer-treatment toxicity decisions require oncology coordination, realistic prognosis and rehabilitation.
Visual loss may arise away from the tumour
Paraneoplastic ocular disease results from an effect of a malignancy rather than direct invasion or ordinary metastasis. Cancer-associated retinopathy, melanoma-associated retinopathy and bilateral diffuse uveal melanocytic proliferation are important examples. Symptoms can precede a known cancer diagnosis. The eye may look relatively normal early despite serious functional loss, so unexplained bilateral photopsias, night blindness or field change deserves a structured assessment.
Ask about tempo, systemic symptoms, cancer history and treatment exposure. Measure acuity, colour and fields, examine the retina and obtain appropriate OCT and electrophysiology. Consider inherited degeneration, toxic retinopathy, nutritional disease and infection as alternatives. A temporal association with cancer is informative but does not prove a paraneoplastic mechanism.
CAR and MAR
Cancer-associated retinopathy (CAR) can affect photoreceptor function and present with photopsias, progressive field loss and reduced vision. Anti-retinal antibodies, including recoverin antibodies in selected cases, may support the assessment. Antibody testing has specificity and interpretation limitations: positive antibodies can occur outside the suspected syndrome, and a negative panel does not exclude every autoimmune retinal process.
Melanoma-associated retinopathy (MAR) often involves night blindness, photopsias and an electronegative ERG pattern reflecting ON-bipolar dysfunction. TRPM1-directed antibodies have been demonstrated in primary research. Distinguish the pattern from congenital stationary night blindness, retinoschisis and acquired vascular disease. Adult onset, melanoma context and the wider assessment help explain why the same ERG pattern can mean a different disease.
Coordinate cancer investigation or review with oncology. Treatment of the underlying malignancy and selected immunomodulation may be considered, but response is variable and no single antibody result guarantees benefit from a particular regimen. Follow both objective function and the patient's ability to navigate, read and cope with glare.
BDUMP
Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a rare paraneoplastic syndrome with bilateral uveal changes, often rapid visual decline, characteristic RPE abnormalities, exudative detachments and cataract. Multiple pigmented or nonpigmented uveal lesions may appear. These findings should prompt consideration of an associated extraocular malignancy rather than an assumption of simultaneous independent ocular melanomas.
Use multimodal imaging and systemic investigation with specialist teams. Proposed treatments, including plasma exchange in selected reports, have limited and variable evidence. Do not describe a case-series response as a proven cure. Distinguish direct choroidal metastases and other causes of bilateral exudative change because their treatment strategies differ.
| Syndrome | Functional or structural clue | Interpretive caution |
|---|---|---|
| CAR | Photoreceptor dysfunction and visual-field loss | Antibodies are not standalone proof |
| MAR | Night symptoms and electronegative ERG | Similar patterns occur in nonparaneoplastic disease |
| BDUMP | Bilateral uveal proliferation and RPE change | Requires systemic malignancy assessment |
| Treatment toxicity | Relation to therapy and dose or timing | Exclude tumour progression and other causes |
Complications of cancer treatment
Radiation can cause retinopathy, macular oedema, cataract, optic neuropathy, surface injury and neovascular glaucoma according to the treated field and dose. The latency and clinical pattern matter. Anti-VEGF and other selected interventions may address complications, but visual outcome depends on the underlying tissue injury. New visual loss after radiotherapy should not automatically be attributed to radiation without excluding tumour recurrence or another emergency.
Systemic cancer therapies can produce inflammatory, vascular, surface and retinal effects. Immune checkpoint treatment can cause ocular inflammation, while targeted agents can have characteristic retinal fluid or other toxicity patterns. Coordinate diagnosis and decisions about continuing, pausing or altering treatment with oncology. The ophthalmologist should describe severity and risk, rather than independently withdrawing a life-prolonging medicine without a coordinated plan when consultation is possible.
Surgery and eye removal also have long-term effects, including refractive change, diplopia, socket problems and adaptation to monocular vision. Include rehabilitation and fellow-eye protection in follow-up. A stable tumour measurement alone does not establish that the patient's functional needs have been met.
Prognosis and informed discussion
Separate local tumour control, preservation of vision and systemic survival when explaining outcomes. Prognostic genetic or staging results estimate risk and have uncertainty; avoid converting a population percentage into a promise for an individual. Ask how much detail the patient wants and include support for anxiety, family concerns and work or driving implications.
A patient with rapid bilateral night-vision loss and melanoma needs electrophysiological and paraneoplastic assessment, not only a search for a visible metastasis. Another with new oedema after radiotherapy needs complication treatment and confirmation of tumour status. In both cases, state the mechanism, coordinate systemic care and provide rehabilitation while diagnostic work continues.
Sources: Primary MAR TRPM1 study, primary BDUMP study and EBO oncology curriculum.
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