Posters

Ocular surface squamous neoplasia in new zealand: high prevalence of a rare pathology

Poster Details

First Author: R.Hossain NEW ZEALAND

Co Author(s):    J. McKelvie                    

Abstract Details

Purpose:

Ocular surface squamous neoplasia (OSSN) constitutes a spectrum of conjunctival and corneal squamous cell carcinomas (SCC) with documented higher incidence in the Southern hemisphere. Risk factors include ultraviolet exposure, male gender, and fair complexion. Management options include surgical excision of suspected lesions and/or topical chemotherapy, including Mitomycin-C. Although OSSN is a curable cancer with a low mortality rate, it remains a medical and economic burden. Presently there is limited published epidemiological data for New Zealand (NZ), an area with a high ultraviolet index.

Setting:

This study aimed to identify the prevalence of histology-confirmed OSSN cases within the Waikato region, NZ’s fourth largest region and a largely rural area encompassing 9.6% of NZ’s total estimated population.

Methods:

A retrospective observational study of Waikato region patients with histology-confirmed OSSN from 1 January 2000 to 31 December 2019 was completed in two phases. In phase 1, histology reports of all conjunctival biopsies performed at the publicly funded hospital between 1 January 2000 and 31 December 2009 were reviewed. In phase 2, data collection was extended to include all conjunctival specimens sent for histology from the two private Ophthalmology practices between 1 January 2010 and 31 December 2019. Information analysed included gender, ethnicity, age at time of excision and histology diagnoses.

Results:

Out of 1289 excised conjunctival lesions, 512 (40%) were sent for histology evaluation and 111 cases of OSSN were diagnosed. Patients had an average age of 69, were predominantly male (73%), and most commonly of NZ-European ethnicity (59%). Over the twenty year period, 55% of lesions were diagnosed as severe dysplasia (14%), full thickness dysplasia (33%) or invasive SCC (8%). In phase 1, less lesions were excised with 77% graded as severe dysplasia or worse. In phase 2, nearly four times as many biopsies were performed and 53% of lesions were graded as moderate dysplasia or better.

Conclusions:

This is the largest study to analyse NZ OSSN rates. Although only 40% of samples were sent for histology, the 22% of positive samples in this cohort was significantly higher than other studies, including 9.8% previously reported in Australia. Routine use of histology for conjunctival samples 1) enables early diagnosis of OSSN and 2) is essential to assess accurately the high rates and associated risk factors for OSSN.

Financial Disclosure:

None