Epidemiology of melanoma in situ in New Zealand: 2008-2012

The incidence of melanoma in situ varies throughout the world. It is associated with excellent outcomes, however many of those untreated will go on to develop invasive melanoma with a worse prognosis. There is no previously published data on melanoma in situ (MIS) in New Zealand. Further information is needed to enable better understanding of the disease spectrum.

De-identified data were obtained from the New Zealand Cancer Registry (NZCR) by way of computerised search for MIS diagnosis. A separate search was performed to identify all patients with invasive melanoma. World Health Organization standard population was used for calculating age standardised rates.

There was a trend to increasing cases of MIS, but a relative plateauing of invasive melanoma. The number of cases for MIS overtook invasive melanoma in 2012. Overall, men had a significantly higher incidence compared to women. Incidence rates varied markedly between different regions of the country.

This paper provides new information about the epidemiology of MIS in New Zealand and its relevance to clinical practice. Public education strategies may be beginning to show effect with the goal of increasing prevention and earlier detection and treatment to enable decrease in melanoma mortality.