Geographical variation of incidence of cutaneous melanoma in Queensland.

OBJECTIVE

The study investigated geographical differences and time trends of incidence rate and body site distribution of cutaneous melanoma in Queensland.

DESIGN

Analysis of data recorded by Queensland Cancer Registry.

PATIENTS

Analysis included 34 021 patients with invasive and 10 710 patients with in situ melanoma diagnosed between 1982 and 2002.

MAIN OUTCOME MEASURES

Age-standardised incidence rates (world standard population) per 100 000 inhabitants of cutaneous melanoma and annual percentage change (APC).

RESULTS

Yearly age-standardised incidence rates of invasive melanoma averaged over the 21 years of observation were highest in the south-eastern part of the state, notably in the statistical division Moreton for men (54.2) and in Fitzroy for women (51.4). Inland divisions had on average lower rates than coastal areas. For both men and women, age-standardised incidence rates of invasive and of in situ melanoma increased between 1982 and 2002 for Queensland as a whole and for almost all its statistical divisions. For invasive cancer, the increase was strongest for Moreton (APC men: 5.4%; women: 4.5%; P < 0.001, respectively). APCs were higher for in situ melanoma compared with invasive melanoma for all statistical divisions and both genders. In both genders, the increase in invasive rates was most pronounced for the trunk (APC men: 3.2%, P = 0.040; women: 2.3%; P = 0.306).

CONCLUSIONS

The south-eastern corner of Queensland endured the main burden of melanoma. Behavioural and lifestyle choices might create the observed differences between statistical divisions. The increase in trunk melanomas is discussed with respect to aetiology.