A Contemporary Appraisal of Ocular Melanoma in New Zealand (Aotearoa)

This thesis represents a contemporary appraisal of ocular melanoma in New Zealand (Aotearoa), providing fundamental knowledge on uveal and conjunctival melanoma in a population with an exceptionally high burden of cutaneous melanoma. Seven nationwide studies, both prospective and retrospective, spanning 21 years, were completed. For uveal melanoma, a multi-platform, multi-centre approach for data collection was conducted to accurately estimate the true incidence of uveal melanoma; as approximately one-third of patients received treatment that did not result in histological diagnosis and was therefore not included in the national cancer registry. The results demonstrate that NZ has the highest incidence of uveal melanoma in the Southern Hemisphere – affecting approximately 11.5 (crude) and 8.2 (age-adjusted) persons per million population, typically affecting those with a predisposing phenotype of fair skin and light iris colour. Despite the increased incidence, survival following treatment was comparable to international centres for those undergoing treatment modalities resulting in a histopathological diagnosis (biopsy or enucleation). For small-to-medium-sized uveal melanoma treated with ruthenium-106 plaque brachytherapy, ocular morbidity and disease-specific mortality were better than the preceding iodine-125 radioisotope used in NZ and overall outcomes were favourable when compared to international standards. Optometrists in NZ play a crucial role in detecting suspicious pigmented eye lesions – referring two thirds of all suspicious lesions reviewed in the national ocular oncology service, while also monitoring a number of benign pigmented lesions in the community. A new MRI protocol to image iris lesions using a readily available 3T MRI scanner was developed – representing an advancement in ocular oncology imaging, and the characteristics of histologically-verified iris melanoma described. Notably, the incidence of conjunctival melanoma in a region with significant ultraviolet radiation was unchanged in the last two decades, possibly ascribable to a population change in behaviour towards sunlight exposure, following mass health campaigns directed at reducing cutaneous melanoma. Whilst these studies provide a strong foundation on the epidemiology, referral patterns, investigations and treatment outcomes for ocular melanoma in NZ, more research is required to address the literature gap for this disease in this region. Future multicentre collaborations on ocular melanoma, especially in the Pacific region, are indicated.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Ophthalmology

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2024

Author dc:creator

• Lim, Joevy

Advisors dc:contributor.advisor

• McGhee, Charles
• Misra, Stuti
• Gokul, Akilesh

• Ocular melanoma
• uveal melanoma
• conjunctival melanoma
• epidemiology
• uveal ring melanoma
• MRI
• plaque brachytherapy
• ocular oncology

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/74026

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/74026