Abstract
Purpose: :
To study the incidence of malignant conjunctival melanoma in Sweden during the period from 1960 to 2005, with respect to age distribution, gender and changes in incidence over time.
Methods: :
Patients with conjuctival melanoma were identified through the Swedish Cancer Registry and cross-checked against hospital files. Of the 170 cases included in this study, 166 (97.6%) were confirmed by microscopy. For the other 4 cases (2.5%) no samples were found and the pathological examination was not possible. The crude and age-standardized incidences were estimated separately for each gender using the Swedish population of 1970 to 1974 as a standard and the annual change in incidence over time was estimated using a regression model with logarithmic incidence numbers.
Results: :
In total 170 patients met the criteria, of whom 89 were males and 81 females. During the 46-year period, the age-standardized incidence of conjunctival melanoma increased significantly in the male population from 0.10 cases/million to 0.74 cases/million ( P < 0.001). The same trend was observed in the female population with an increase from 0.06 cases/million to 0.45 cases/million (P = 0.007). The age-standardized incidence of conjunctival melanoma between genders showed no significant differences. The annual relative change in age-standardized incidence was 16.9% (95% CI, 12.2% - 21.6%) in males and 19.5% (95%CI, 9.3% - 29.7%) in females. The age-specific incidence revealed a significantly higher incidence in men 65 years and older (1.48 cases/million) compared to men younger than 65 (0.3 cases/million). The same occurred in women 65 years and older where the age-specific incidence (1.39 cases/million) was significantly higher compared to women younger than 65 years (0.2 cases/million).
Conclusions: :
A population based investigation performed to establish the incidence of conjunctival melanoma in Sweden during the period of 1960 to 2005 revealed an increasing incidence in both the male and female population.
Keywords: conjunctiva • melanoma • clinical (human) or epidemiologic studies: prevalence/incidence