Ocular surface squamous neoplasia with orbital tumour extension: risk factors and outcomes.

Purpose: To describe the risk factors, clinical features, histopathology, treatment, and outcomes of patients with orbital tumour extension of ocular surface squamous neoplasia (OSSN).

Methods: Retrospective study of 51 patients with orbital tumour extension (cases) and 360 patients without orbital extension (controls).

Results: Of 1,653 patients with OSSN, orbital tumour extension was noted in 51 (3%) cases. The risk factors for orbital tumour extension included outdoor occupation (p < 0.03; Odds ratio (OR) = 1.96), Human Immunodeficiency Virus (HIV) infection (p < 0.0001; OR = 5.81), prolonged duration of symptoms (p = 0.01; OR = 1.02), tumour bilaterality (p = 0.02; OR = 2.92), forniceal and tarsal conjunctival involvement, diffuse tumour (p < 0.0001; OR = 9.13), inferior quadrantic location (p < 0.0001; OR = 7.51), increased tumour thickness (p = 0.04; OR = 1.59), higher % of ocular surface involvement (p = 0.002; OR = 1.12), nodular (p = 0.002; OR = 2.61) and nodulo-ulcerative (p < 0.0001; OR = 11.05) tumour morphology, poorly differentiated tumours (p = 0.006; OR = 4.23); invasive squamous cell carcinoma (SCC) (p < 0.0001; OR = 29.76), spindle cell and mucoepidermoid variant (p = 0.02; OR = 16.94) tumours. At a mean follow-up period of 27 months, tumour recurrence in the socket was noted in 1 (2%), locoregional lymph node metastasis (LNM) in 15 (29%) patients, and nine (18%) patients died due to systemic metastasis (SM). T4 tumour at presentation was a risk factor for LNM (p = 0.01; Hazard ratio (HR) = 5.60) and SM (p = 0.0003; HR = 5.09).

Conclusion: Orbital extension of OSSN is rare. Outdoor occupation, HIV infection, larger and thicker tumours in the inferior quadrant with forniceal and/or tarsal conjunctival involvement with nodular or noduloulcerative morphology, poor tumour differentiation, SCC, spindle cell and mucoepidermoid variants on histopathology are at increased risk for orbital tumour extension.