About 25% of patients with conjunctival malignant melanoma developed metastatic disease during long-term follow-up in a retrospective study published in BMJ Open Ophthalmology.

Researchers analyzed outcomes in 167 patients treated between 1985 and 2013 at two German centers. Mean follow-up was 78 months, and the average age at diagnosis was 63 years. Most tumors were clinically staged as cT1, involving the bulbar conjunctiva.

Local recurrence occurred in 47% of patients at a mean of 42 months. Overall, 25% developed metastases. Regional lymph node metastasis occurred in 31 patients at a mean of 49 months, and distant (hematogenous) metastasis occurred in 24 patients at a mean of 56 months. Fourteen patients experienced both regional and distant spread.

Tumor location and stage were associated with metastatic risk. cT1 bulbar tumors were linked with lower rates of lymphatic and distant metastasis. In contrast, cT2 tumors—particularly those involving the caruncle, fornix, or tarsal conjunctiva—were associated with higher metastatic risk. Multifocal tumors were associated with increased risk of regional lymphatic spread and also showed higher rates of distant metastasis.

Pathologic staging showed similar trends. pT1 tumors were associated with lower rates of distant metastasis compared with higher-stage tumors. However, among patients with pT1 disease treated with excision alone, metastatic risk was comparable to that of more advanced tumors. In contrast, pT1 tumors treated with adjuvant therapy were associated with lower rates of systemic spread.

Adjuvant therapy was administered in approximately three-quarters of patients. Among treatment modalities, Ruthenium-106 brachytherapy was associated with a lower risk of hematogenous metastasis.

Importantly, patterns of spread followed a sequential course. Patients who developed regional lymph node metastasis had a markedly increased risk of subsequent hematogenous dissemination. Local recurrence was also strongly associated with distant metastasis, reinforcing the link between local and systemic disease progression.

The authors noted that these findings clarify the relationship between clinical stage, tumor location, recurrence, and metastatic progression. The data may help refine risk stratification and guide surveillance strategies in patients with conjunctival melanoma.

The study was limited by its retrospective design and long study period.

The authors reported no competing interests.

Source: BMJ Open Ophthalmology