Aim: To examine the incidence of thick melanoma in New Zealand from 1994-2004 and investigate associations with melanoma thickness.
Method: The New Zealand Health Information Service provided information on all registrations for malignant melanoma from 1994-2004. Age-standardised registration rates were calculated. Logistic regression analysis was undertaken to identify factors associated with melanoma thickness.
Results: The incidence of thick melanoma did not decrease during 1994-2004. There were statistically significant associations for age, gender, ethnic group, and type of melanoma with melanoma thickness. Of those diagnosed with melanoma, the proportion with thick melanoma was greater for older than younger people, for males compared with females, for Maori compared with non-Maori (despite the lower incidence in Maori), and for those diagnosed with nodular melanoma compared with other types of melanoma.
Conclusion: Strategies to encourage the early detection of melanoma in New Zealand have not yet reduced the incidence of thick melanomas. This may be because it is too soon to see the impact of early detection, or because early detection strategies predominantly identify melanomas that are unlikely to progress, but miss thicker nodular melanomas.