Estimating malignancy risk of melanocytic choroidal tumours detected in the Australian National Eye Health Survey

Abstract

ABSTRACT Clinical relevance: The malignant potential of choroidal melanocytic tumours detected incidentally in the community is thought to be low, but this has not been assessed using a validated screening tool. An accurate characterisation of the malignant potential of these lesions has implications for resource allocation, service provision, education, and training. Background: MOLES (Mushroom shape, Orange Pigment, Large size, Enlargement, and Subretinal fluid) categorises tumours as ‘common naevus’, ‘low-risk naevus’, ‘high-risk naevus’, and ‘probable melanoma’. The MOLES system recommends that patients with common naevi (score = 0) undergo review by a community optometrist every two years, ideally with sequential colour photography. For the remaining patients (score ≥ 1), specialist imaging and assessment are recommended, with referral triaged as non-urgent for patients with low-risk (score = 1) or high-risk naevi (score = 2) and urgent for patients with probable melanoma (score > 2). Methods: Lesions flagged as choroidal melanocytic tumours on retinal photographs taken during the Australian National Eye Health Survey were retrospectively analysed by an ocular oncologist. Each lesion was assigned a MOLES score and categorised as common, low-risk, high-risk or probable melanoma. Results: Seventy-seven choroidal naevi were identified. Seventy-five (97%) of the choroidal naevi were categorised as common naevi, with a MOLES score of 0. Two (3%) choroidal naevi had a score of 1 and diagnosed as low-risk naevi due to their size. No naevi had a score of 2 or more. Conclusion: All choroidal naevi detected in this nationally representative population survey were innocuous. This suggests that the vast majority of choroidal melanocytic tumours that are incidentally detected in Australia can be managed in primary eye care settings without the need for specialist referral. MOLES provides a simple evidence-based method for choroidal naevi assessment in primary care.