Cutaneous melanoma in New Zealand: 2000-2004.

BACKGROUND

In 2004, we published data on the trends in New Zealand (NZ) cutaneous melanoma (CM) for the period 1995-1999. The present report documents the trends in the next period from 2000 to 2004.

METHOD

Data were obtained from the New Zealand Cancer Registry by way of a computerized search of CM ICD-10 (172) codes from 2000 to 2004. Only one registration per person was made to avoid including patients with metastatic melanoma. The exclusion criteria were: incorrect or absent data; benign naevi; and melanoma in situ. Incidence rates were age standardised to the Segi world population.

RESULTS

The total study population was 8262 patients. There was no increase found in the overall incidence rate over the time period, but men had a statistically higher overall incidence rate (P= 0.0002) and thicker CMs (P= 0.003) compared with women. This gender difference was particularly marked in those patients aged greater than 59 years. Breslow thickness increased from 0.7 to 0.8 mm. The incidence rates varied quite significantly among District Health Boards, with Taranaki having the highest rate (70.3/100 000/year) and Southland had the lowest rate (20.1/100 000). Overall, NZ had a CM incidence rate of 41.2/100 000/year).

CONCLUSION

The current study confirmed that NZ has the highest overall CM incidence rate in the world. Elderly men (>59 years old) have the highest risk of developing melanoma. The increase in melanoma thickness with its associated higher mortality risk is of grave concern.