Ocular surface squamous neoplasia in Northern Thailand: a 16-year review

Abstract

Purpose To evaluate clinical characteristics, treatments, and outcomes in patients with ocular surface squamous neoplasia (OSSN) at a tertiary center in Northern Thailand. Methods Patients diagnosed with either corneal-conjunctival intraepithelial neoplasia (CIN) or squamous cell carcinoma (SCC) from May 2000 to December 2015, were recruited. The patients’ demographics, symptoms, clinical characteristics, cytopathology, treatments, and outcomes were reviewed. Results Overall 171 eyes from 168 patients, 92 eyes were CIN and 79 eyes were SCC. Males were affected in 65.5%. The mean age was 58.8 ± 16.8 (29–99) years. In most cases (60.3%), the tumors were located at the limbus. The most common clinical characteristic was papilliform appearance (46.2%). Human immunodeficiency virus (HIV) infection was found in 37 (22.0%) patients with a mean age of 40.5 ± 7.7 years. The treatments and outcomes were evaluated in 136 eyes whose main initial treatment was wide excision with adjunctive cryotherapy (47.8%), followed by topical mitomycin C (30.9%). The mean follow-up time after treatment was 20.8 ± 2.2 (3–110) months and the recurrence occurred in 18 eyes (13.2%) during the follow-up period. The mean recurrence-free time (months) for CIN was significantly longer than that of SCC (81.3 ± 10.0 [95%CI 61.5 – 101.1] vs 33.2 ± 4.6 [95%CI 24.0 – 42.3], p = 0.030). SCC was the only significant risk factor that influences the recurrence of the tumors with the adjusted hazard ratio of 5.69 (p = 0.005). Conclusion OSSN in Northern Thailand usually involved a limbal area and presented as a papilliform mass. HIV infection should be suspected in young patients. CIN had better outcomes after treatments than invasive SCC.

Clinicopathological Correlates of Ocular Surface Squamous Neoplasia

“…Higher levels of UV-B exposure in Malawi, Thailand, and India (with population-weighted average daily ambient UV radiation levels of 5,019 J/m 2 , 4,862 J/m 2 , and 4,514 J/m 2 , respectively) seem to correlate with the higher proportions of invasive disease in these regions, while Taiwan (2,908 J/m 2 ), which has similar levels of UV-B radiation to our population (3,206 J/m 2 ) had a comparable low rate of invasive disease to that of our study [12, 22, 26‒28]. However, this trend did not hold across all countries, as the recent New Zealand-based study by Hossain et al (2022) had higher rates of invasive disease despite substantially lower UV-B radiation (2,487 J/m 2 ), while Shields et al (2017) found significantly higher rates of invasive disease despite similar levels of radiation exposure (2,736 J/m 2 ) [11, 18].…”

“…UV-B radiation exposure also potentially plays a role in this trend [20]. The younger mean age of diagnosis in Malawi, Thailand, and India could potentially be explained by the higher rates of UV radiation exposure in these regions, a known pathogenic risk factor for OSSN development [22, 26‒28]. Conversely, Taiwan had a comparable higher mean age of diagnosis to our study, reflecting the similar levels of UV-B radiation in that region [12].…”

Demographics, clinical presentation and risk factors of ocular surface squamous neoplasia at a tertiary hospital, South Africa

“…This is in keeping with large studies and follows the pathophysiology of OSSN, which is thought to originate from the limbal stem cells [ 7 , 13 – 16 ]. OSSN is also most commonly reported in the interpalpebral space, with the nasal quadrant mostly affected [ 14 , 15 ]. This is hypothesised to be due to the amplification of UVB radiation on the nasal limbus [ 16 ].…”

“…The large number of pigmented lesions in our study is likely due to our predominantly black African cohort where more pigmentation has been reported than in white patients [ 17 ]. Pigmentation in OSSN lesions has a significant regional variation and has been reported at 1% in a white cohort, 9% in a Thai cohort, 78% in an Indian cohort, and 55% in our mostly black African cohort [ 14 , 15 , 18 ]. Mild and moderate pigmentation likely represents complexion associated melanosis.…”

“…A fibrovascular lesion was more likely to be benign, whereas a leukoplakic or gelatinous lesion was more likely to be OSSN. Kaliki et al [ 14 ] in India and Tananuvat et al [ 15 ] in Thailand found papilliform lesions to be the most common morphological type, whereas Gichuhi et al [ 17 ] in Kenya found a predominance of leukoplakic lesions. This regional difference may be attributed to different associated risk factors such as HPV infection, which could be reviewed in further studies.…”