Abstract
BACKGROUND: Ocular surface squamous neoplasia (OSSN) is a relatively rare disease with a low mortality and highly variable incidence. Despite a high incidence of OSSN in the Southern hemisphere, there is limited epidemiological data for New Zealand. The current study aims to assess the incidence, demographics, and histological grade of OSSN in the Waikato region of New Zealand, home to ~10% of the population of New Zealand. METHODS: Non-interventional retrospective cohort study. All conjunctival biopsy histology reports from 2010 to 2019 in the Waikato region of New Zealand were analysed. Age, sex, and ethnicity were analysed and the incidence of OSSN was calculated. Main outcome measures included histological grade, rate of recurrence, and incidence of OSSN. RESULTS: A total of 386 patients underwent conjunctival biopsy with histology during the study period. Eighty-three lesions (22%) involving 80 patients (21%) were reported positive for OSSN. Patients with OSSN had a mean age of 68.9 years (SD = 13.2), were predominantly male (76%), and of New Zealand-European ethnicity (53%). Conjunctival intraepithelial neoplasia-1 (30%) was the most frequent diagnosis. Three patients (4%) had recurrent lesions requiring repeat biopsy. The peak annual OSSN incidence rate was 3.81/100,000 population in 2019. The overall ten-year incidence was 2.13/100,000 population/year. CONCLUSION: This is the largest study to investigate OSSN incidence in New Zealand. The incidence rate of OSSN is one of the highest rates reported in the literature.