Demographics, clinical features and prognosis of patients with primary malignant conjunctival tumors at a tertiary hospital in Japan.

Purpose: To clarify the demographic characteristics, clinical features and prognosis of patients with primary malignant conjunctival tumors diagnosed at a single tertiary hospital in Japan.

Study design: Retrospective, observational case series.

Methods: Patients with malignant conjunctival tumors diagnosed histopathologically at Tokyo Medical University Hospital between 2010 and 2022 were retrospectively reviewed. The demographic profile, clinical features and treatment outcomes were analyzed.

Results: A total of 359 patients with histopathologically proven malignant conjunctival tumors were included. All patients were Japanese. The most common malignant conjunctival tumor was lymphoma (n = 197, 54.9%), followed by squamous cell carcinoma (SCC) (n = 97, 27.0%), melanoma (n = 60, 16.7%), and others (n = 5, 1.4%). The mean age of patients at the time of diagnosis was 60.5 ± 17.4 years for lymphoma, 60.2 ± 15.8 years for SCC, and 65.8 ± 15.7 years for melanoma. Among 197 patients with lymphoma, 89.3% had extranodal marginal zone lymphoma (EMZL). Lymphomas were treated with external beam radiation therapy in 52.8%, surgical resection with or without cryopexy in 40.1%, and systemic chemotherapy in 4.0%. During an observation period of more than 12 months, recurrence was observed in 8.4% and extraocular lymphoma occurred in 1.7%. In SCC and melanoma, common surgical resection with sufficient safety margin, cryopexy, and application of 0.04% mitomycin C were performed as eye-preserving therapy. Orbital exenteration was performed in advanced cases. Recurrence rates and regional lymph node metastasis rates during an observation period of more than 12 months were, respectively, 30.1% and 6.2% in SCC. Recurrence rates and regional lymph node or distant organ metastasis rates during an observation period of more than 24 months for melanoma were 29% for both. Tumor-related mortality was 16% in melanoma, but 0% in lymphoma and SCC.

Conclusions: Lymphoma was the major malignant conjunctival tumor in a Japanese ophthalmology referral center, which may reflect a unique epidemiological trend in Japan compared to Western countries. The prognosis of lymphoma and SCC after appropriate treatment was favorable, except for some cases of advanced SCC.