Abstract
Abstract: :
Purpose:To examine variations in mortality for patients with conjunctival melanoma in the United States over a 26 year period for 1973–1999. Methods:Data from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program Database (1973–1999) were analyzed using the SEER*Stat software. Cases for analysis were defined using International Classification for Diseases for Oncology Second Edition(ICDO–2) histology codes for melanoma (8720–8790) and site codes for conjunctiva (C69.0) and cornea (C69.1). 21 (1%) of the cases were coded with the cornea as the primary site. These were recoded as conjunctival melanoma because melanoma of the cornea is thought to extend from the conjunctiva. Relative survival rates for patients diagnosed with conjunctival melanoma between 1973 and 1999 were calculated by the life table method and adjusted for heterogeneity of withdrawal. Univariate analysis of relative survival curves was done using the Cox proportional hazards model with the level of significance set at P≤0.005. The relative risk ratio was calculated for each factor along with the 95% confidence interval. Results:For the period 1973–1999, 217 cases of conjunctival melanoma were identified in the registry. 212 (98%) of these were reported by a hospital or laboratory. 214 (99%) were confirmed histopathologically. A greater proportion of the cases were male than female (male=127 (58.5%), female 90 (41.5%), P=0.0071]. When adjusted for their proportions in the population, there was a statically significant greater proportion of whites 92.8% than blacks 2.8% (X2=10.644, P=0.0011). The age at diagnosis ranged from 8 to 96 years with a mean of 61.8 years Survival analysis was performed on all histopathologically confirmed cases diagnosed between 1973 and 1999. The observed survival rate after five years was 72.6% (74.1% in males and 70.4% in females) and 46.5% (42.8% in males and 51.7% in females) after ten years. The five–year relative survival rate was 86.8% (88.1% in males and 84.8% in females). The ten–year relative survival rate was 67.5% (61.0% in males and 76.7 % in females). Univariate analysis showed younger age at diagnosis to be correlated with improved survival (P<0.001). Year of diagnosis and gender did not reach statistical significance in univariate analysis. Conclusions:Analysis of data from the SEER Program database indicates a high mortality rate for patient with conjunctival melanoma in the Unites States. The five–year and ten–year survival rates of 72.6% and 46.5% respectively are similar to those found for uveal melanoma in other studies. Younger age at diagnosis correlated with improved survival.
Keywords: melanoma • conjunctiva • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology