Ocular oncology surgery

Ocular oncology surgery covers different procedures for eye tumours rather than one operation. For squamous neoplasia of the eye surface—abnormal growth in its surface cells—surgical excision removes the affected tissue. Medicines applied to the eye surface offer another treatment approach. For choroidal melanoma, a cancer inside the eye, iodine-125 plaque brachytherapy delivers radiation from a plaque placed against the outside of the eye; this differs from enucleation, which removes the eye. Proton therapy is another form of radiation treatment for ocular tumours. Its planning combines eye imaging, assessment by an eye specialist and surgery to place clips.

The alternatives depend on the particular eye condition. For ocular surface squamous neoplasia, treatments studied alongside excision include medicines applied to the eye: fluorouracil, interferon alfa-2b and mitomycin-C. These comparisons concern surface disease, not melanoma inside the eye. A separate diagnostic procedure, vitrectomy for biopsy, can help identify the cause of unexplained disease affecting the vitreous, retina or choroid—the gel inside the eye and tissues at the back of the eye. Its purpose is to help establish a diagnosis, rather than to establish that cancer has been removed. After radiation treatment for uveal melanoma, selected patients may need further surgery inside the eye to manage damage associated with remaining dead tumour tissue. This is a different situation from choosing the initial cancer treatment.

In the COMS trial, the iodine-125 plaque treatment group included 650 treated patients with choroidal melanoma. Their tumours measured 2.5–10.0 mm in height and no more than 16.0 mm across the base. Patients entered the trial between 1987 and 1998, so these are historical treatment results. Follow-up lasted at least one year for 638 patients and at least five years for 411. Within the first five years, 69 eyes were removed and treatment failure was reported in 57 eyes. Treatment failure meant tumour growth, recurrence or spread through the outer wall of the eye. The estimated five-year risk was 12.5% for eye removal and 10.3% for treatment failure, calculated using a method that accounts for differences in follow-up time. These results describe plaque treatment in this defined patient group, not expected results for every eye tumour or a direct comparison with eye-removal surgery.

For ocular surface squamous neoplasia, dry eye was the most commonly reported side effect across surgical excision and the topical medicines studied. For choroidal melanoma treated with a radiation plaque, further treatment can include removal of the eye; tumour treatment failure was the most common reason for this within the first three years in the COMS trial. After radiation for uveal melanoma, dead tumour tissue remaining inside the eye can cause toxic tumour syndrome, a serious blood-vessel complication that threatens the eye and its function. Surgery inside the eye has been used to prevent or treat this complication in selected patients, with the choice and timing depending on the tumour and the condition of the eye.

Follow-up after treatment can address both the treated eye and the possibility of cancer spreading elsewhere. In the COMS plaque-treatment trial, eye examinations included ultrasound and photographs of the back of the eye before treatment, every six months for five years, then annually. This was the trial’s schedule. For uveal melanoma, control of the tumour in the eye does not eliminate the possibility of spread, particularly to the liver. A Scottish consensus statement published in 2023 describes follow-up for posterior uveal melanoma based on low-to-medium or high risk of spread. That framework was adopted in Scotland, but it was consensus-based because adequate evidence to establish the surveillance strategy was lacking; it is not a universal follow-up schedule.