COMS Study findings

Last updated: October 2026

The Collaborative Ocular Melanoma Study (COMS) remains the foundation of modern choroidal melanoma management — but the field has moved meaningfully since its landmark publications, particularly around radiation dosing.

Core COMS findings (still the reference standard)

Standard brachytherapy protocol per COMS: Iodine-125 plaque delivering 85 Gy to the tumour apex (or 5mm depth, whichever is greater) — this became the long-standing gold standard for medium-sized uveal melanoma.

What's changed: the move toward lower, individualized dosing

A significant current trend, reflected in 2024-2025 literature, questions whether the COMS 85 Gy apex dose is higher than necessary for many tumours:

• Several series (e.g., 62.5 Gy protocols) have achieved local control rates comparable to COMS (roughly 9-10% recurrence) with substantially less radiation delivered to the lens, optic disc, and fovea
• American Brachytherapy Society (ABS) guidelines now support dosing to the actual tumour apex height rather than defaulting to a fixed 5mm depth for smaller tumours — reducing unnecessary radiation to critical structures without compromising tumour control
• A 2025 review of over 3,000 patients across 20 studies found only a weak relationship between apex dose and recurrence risk, reinforcing that higher dose does not proportionally improve control
• The clinical rationale: personalized, lower-dose plaque design aims to balance tumour control with preserving vision — particularly relevant for smaller tumours where lens and macular toxicity from a full 85 Gy dose can be the dominant cause of vision loss, rather than the tumour itself

Practical implication for residents

Know the COMS findings as the historical foundation (equivalence of brachytherapy and enucleation for medium tumours; no benefit to pre-enucleation radiation for large tumours) — but be aware that contemporary ocular oncology practice increasingly individualizes radiation dose downward from the classic 85 Gy protocol, especially for smaller tumours, based on more recent dosing evidence.

Key references: COMS Report No. 18. Arch Ophthalmol. 2001;119:969-982.  |  Echegaray JJ, et al. Brachytherapy for Uveal Melanoma: Is the Dose Too High? Retinal Physician. 2024.  |  AAO. Diagnosis and Management of Choroidal Melanoma, EyeNet, 2024.