Conjunctival melanoma in the Netherlands: a nationwide study

To evaluate risk factors for local recurrence, regional and distant metastases, and mortality associated with conjunctival melanoma.

This was a retrospective study of 194 patients with histologically confirmed conjunctival melanoma diagnosed between 1950 and 2002 in the Netherlands. Data were collected from all university centers and many nontertiary hospitals, using the National Pathology and the Leiden Oncologic Registration Systems. Based on the number of incidences, this study included 70% of the conjunctival melanomas in The Netherlands. Clinical and histopathological data for conjunctival tumors were reviewed and compared with data reported in the literature. Risk factors for local, regional, and distant metastases and survival were analyzed using the Kaplan-Meier and Cox regression analyses.

Of 194 patients with conjunctival melanoma, 112 had a local recurrence (median, 1; range, 1-9) during follow-up (median, 6.8 years; range, 0.1-51.5). Location was the most important risk factor for development of local recurrence, and significantly more occurred with nonepibulbar (log rank, P=0.044) tumors. Significantly fewer local recurrences occurred with tumors initially treated with excision and adjuvant brachytherapy rather than with excision only (log rank, P=0.008) or with excision and cryotherapy (log rank, P <0.038). Forty-one (21%) patients had regional lymph node metastases, mostly to the parotid or preauricular lymph nodes (n=26; 13%). Risk factors for regional metastases were tumor thickness (log rank, P <0.001) and tumor diameter (log rank, P=0.010). Forty-nine (25%) patients (mean, 4.37 years) had development of distant metastases, mainly in the lung, liver, skin, and brain. Tumor-related survival was 86.3% (95% confidence interval [CI], 81.0-91.6) at 5 years, 72% (95% CI, 79.7-64.4) at 10 years, and 67% (95% CI, 58.9-76.1) at 15 years. The main mortality risk factors were nonepibulbar location (log rank, P <0.0001) and tumor thickness (log rank, P=0.0004).

Nonepibulbar tumors more often recur locally and are associated with a shorter survival independent of other risk factors. Tumor thickness is also an important predictor of regional and distant metastases, as well as survival. A prospective study is needed to compare the effect of excision with radiotherapy and excision with cryotherapy on the number of local recurrences, exenteration rate, and survival.