Risk factors and prognosis of orbital exenteration in conjunctival melanoma

To identify the risk factors of orbital exenteration and to evaluate the prognosis of exenterated patients with conjunctival melanoma (CM).

79 consecutive CM patients treated at our centre from January 2000 to September 2021 were included. The demographic, clinical and pathological characteristics were compared between eye-sparing patients and orbital exenteration patients. Main outcomes including progression-free survival (PFS), distant metastasis-free survival (DFS) and disease specific survival (DSS) were assessed in exenterated patients.

The mean follow-up period was 46 ± 39 months. Risk factors for orbital exenteration were identified as worse cT category (OR, 50.75; 95% CI, 5.40-477.07; P = 0.001) and greater tumour thickness (OR, 1.27; CI, 1.04-1.55; P = 0.02). Of the 32 patients who underwent orbital exenteration, three (9.4%) had local recurrence; six (18.8%) experienced regional metastasis; sixteen (50.0%) suffered distant metastasis and fifteen (46.9%) died of metastatic disease. In patients who received orbital exenteration, palpebral conjunctiva involvement (PFS: P < 0.01; DFS: P < 0.05; DSS: P = 0.04), histological ulceration (PFS: P = 0.03; DFS: P = 0.01; DSS: P = 0.03) and regression (PFS: P = 0.01; DFS: P < 0.01; DSS: P = 0.04) were identified as risk factors for poor prognosis. Caruncle involvement (P = 0.01) was also associated with increased risk of melanoma related mortality in exenterated patients.

Histopathological factors should be taken into account when formulating surgical plans for orbital exenteration and when evaluating patients' prognosis following exenteration. For CM patients with caruncle or palpebral conjunctiva involvement, orbital exenteration should be considered for unresectable disease.