Malignant melanoma amongst Maori and New Zealand Europeans, 2000-2004.

BACKGROUND

Although cutaneous melanoma (CM) is rare among dark-skinned populations, it has been found that dark-skinned patients diagnosed with CM tend to have greater Breslow thickness and therefore a worse prognosis.

METHODS

Data was obtained from the New Zealand Cancer Registry pertaining to CM ICD-10 codes from 2000 to 2004. This data was used to compare different ethnicities. We compared New Zealand Europeans with those identifying themselves as Maori. Incorrect or absent data, benign nevi, and melanoma in situ were all excluded from analysis. Only one data entry was accepted per patient to avoid the inclusion of metastases.

RESULTS

Overall, 9004 patients were registered as being diagnosed with CM during 2000-2004, and 7120 with complete ethnicity data were analyzed. A total of 69 cases were identified as Maori. The incidence of CM among Maori is 2.7 per 100,000. Maori had significantly greater Breslow thickness compared with New Zealand Europeans (1.3 vs. 0.80 mm, P < 0.0001). There were differences in type of CM between the two groups (P < 0.00001); in particular, Maori had more acral CM (2.9% vs. 0.8%).

CONCLUSIONS

Cutaneous melanoma is much less common among Maori than among New Zealand Europeans, but Maori have a greater Breslow depth and therefore have a worse prognosis. Increased awareness on behalf of these groups and health care practitioners should assist in ensuring early detection, thereby improving the overall outcome in Maori.