Metastatic disease in conjunctival malignant melanoma: a retrospective analysis of 167 cases

Objective To analyse the data of a cohort of patients with conjunctival melanoma in order to analyse risk and guarding factors and to investigate the impact on metastatic disease with and without adjuvant therapy. Methods and analysis We have retrospectively analysed the impact of clinical aspects and adjuvant therapies after tumour excision or biopsy in 167 patients cared for at the University Hospital Essen and the University Hospital Tübingen, Germany. Clinical as well as histopathological data and therapeutic approaches were analysed with regard to regional (lymphatic) and/or distant (haematogenous) spread during follow-up. The Kaplan-Meier estimate method was used to analyse survival and the Cox regression hazard model to define the probability of metastases depending on different factors. P value of <0.05 was considered statistically significant. Results 167 cases of malignant conjunctival melanoma were retrospectively analysed. The patients received treatment and were followed up for 78.3±67.5 months. Local tumour recurrence occurred in n=79 patients (47.3%) after a mean of 41.5±70.33 months. 30 patients (37.9%) with a recurrence had not received adjuvant therapy. The overall rate of metastasis was 24.5% (n=41). In n=31 cases, regional lymphatic metastases were found after a follow-up of 48.9±63.5 months; in n=24 cases, distant metastases were found, occurring after 55.5±67.4 months. In n=14, the metastatic disease took both pathways. Ruthenium-106 brachytherapy performed in localised melanoma of the bulbar conjunctiva showed a relevant effect of decreasing the risk for haematogenous metastases by 74% (HR=0.256, p = 0.003). 4 out of 54 patients developed distant metastases. Conclusion In conjunctival melanoma, it is important to perform an adjuvant therapy after excision. This reduces not only local recurrences but also significantly the risk for haematopoietic spread.