Conjunctival Melanoma in 430 Cases: Comparative Analysis of the Impact of Orbital Invasion on Tumor Recurrence, Metastasis, and Death.

Abstract

To compare the clinical features at presentation and treatment outcomes of conjunctival melanoma by absence/presence of orbital invasion. A retrospective review of patients with conjunctival melanoma managed at a single tertiary referral center from April 18, 1974, to September 9, 2019. Of 430 patients with conjunctival melanoma, 21 (5%) had orbital invasion at presentation. A comparison between the 2 groups (orbital invasion absent vs. present) revealed that the orbital invasion group had a higher frequency of prior eyelid incisional biopsy (5% vs. 24%, P = 0.006), greater tumor basal diameter (12.2 vs. 17.3, P = 0.009), greater tumor thickness (2.4 vs. 7.0, P < 0.001), more quadrants involved (1.8 vs. 2.5, P = 0.002), and more clock hours involved (4.4 vs. 5.8, P = 0.037). In addition, those with orbital invasion were more likely to undergo exenteration as primary treatment (1% vs. 24%, P < 0.001). Multivariate relative risk regression analysis revealed that variables predictive of orbital invasion included greater tumor thickness (P < 0.001) and greater involvement of the fornix (P = 0.031) and tarsus (P = 0.033). Outcomes revealed orbital invasion group with greater 5-year/10-year distant metastatic rate (16%/21% vs. 63%/63%, P = 0.005), and greater melanoma-related death rate (7%/13% vs. 38%/53%, P = 0.001). Conjunctival melanoma with orbital invasion at presentation demonstrate larger, more extensive tumors involving the fornix or tarsus, and with greater rate of melanoma-related metastasis and death.