Conjunctival melanoma: association of cyclooxygenase‐2 tumour expression to prognosis

Abstract

PurposeConjunctival melanoma is a rare but potentially lethal tumour. Its biologic profile is still largely unknown, with recent studies aiming at establishing histopathological and genetic tumour profiles. The aim of this study was to analyse the association between clinicopathological characteristics and tumour expression of cyclooxygenase‐2 (COX‐2) to prognosis, assessing its usefulness as a possible prognostic marker.MethodsCase series of 50 patients from 1991 to 2008 with pathologically proven conjunctival melanoma. Demographic, clinical and pathological characteristics were evaluated by reviewing clinical files and pathology. Expression of COX‐2 was studied by immunohistochemistry of formalin‐fixed paraffin‐embedded tissue samples of 20 melanomas. Samples were classified in a score which included intensity of staining and percentage of cells with positive reactivity.ResultsClinicopathological features significantly associated (p < .05) with a poor prognosis (death) included involvement of fornix and tarsal conjunctiva, tumour thickness exceeding 2 mm, local tumour recurrence, lymph node and systemic metastasis. In the immunohistochemistry study (n = 20) all cases expressed COX‐2 although with different scores. However, only cases with score 4 were associated with a poor outcome. Multivariate association analysis revealed that recurrence rate, metastasis, corneal invasion and tumour thickness were associated with score 4 cases and, therefore, with a clinical profile with a higher risk of death.ConclusionsResults suggest that higher COX‐2 expression may be a negative prognostic factor in conjunctival melanoma. Further studies can address the potential use of anti‐COX‐2 drugs as adjuvant therapy of this disease.