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Treatment

• Older cat with slow progression of the disease – consider simply performing periodic examinations and serial photography to monitor the progress of the lesion(s)
• Younger cat with rapidly progressive disease – consider removing the eye (enucleation)
• There is some evidence that small, isolated, freckle-like lesions have been successfully treated with laser (diode) photoablation (laser surgery), although no controlled or long-term follow-up studies have been performed to conclusively confirm this
• Mild to moderate diffuse iris involvement – most ophthalmologists prefer a conservative approach consisting of periodic examinations and serial photography to monitor the growth progress of the lesion(s); enucleation is an alternative if progression can be documented or the owner is highly concerned about the potential for spread of the cancer
• Extensive iris involvement resulting in changes in pupil shape or mobility, extra-iris extension, invasion into the drainage angle (where the aqueous humor drains) or secondary glaucoma (high pressure in the eye due to cancerous cells blocking the drainage angle) – enucleation of the eyeball is suggested
• Removal of the eyeball must be undertaken with caution and precision; in humans removal of an eyeball afflicted with cancer has been associated with metastasis to the left orbit or to the body

Living and Management

One long-term study shows that patients with early iris melanoma have no increased risk of life-threatening cancer spread compared to controls, but patients with advanced lesions had dramatically shortened survival times. Your cat's prognosis will depend on if and how much the melanoma has spread within the eye. Your veterinarian will schedule follow-up appointments with you every three months to monitor your cat's intraocular pressure if you decline to have surgery performed on the eye. X-rays to check for metastasis should be taken every six months after the initial diagnosis was made.