Breslow thickness in the Netherlands: a population-based study of 40 880 patients comparing young and elderly patients

BACKGROUND: Melanoma incidence has increased rapidly in the last decades, and predictions show a continuing increase in the years to come. The aim of this study was to assess trends in melanoma incidence, Breslow thickness (BT), and melanoma survival among young and elderly patients in the Netherlands. METHODS: Patients diagnosed with invasive melanoma between 1994 and 2008 were selected from the Netherlands Cancer Registry. Incidence (per 100 000) over time was calculated for young (<65 years) and elderly patients (⩾65 years). Distribution of BT for young and elderly males and females was assessed. Regression analysis of the log-transformed BT was used to assess changes over time. Relative survival was calculated as the ratio of observed survival to expected survival. RESULTS: Overall, 40 880 patients were included (42.3% male and 57.7% female). Melanoma incidence increased more rapidly among the elderly (5.4% estimated annual percentage change (EAPC), P<0.0001) than among younger patients (3.9% EAPC, P<0.0001). The overall BT declined significantly over time (P<0.001). Among younger patients, BT decreased for almost all locations. Among elderly males, BT decreased for melanomas in the head and neck region (P=0.001) and trunk (P<0.001), but did not decrease significantly for the other regions. Among elderly females, BT only decreased for melanomas at the trunk (P=0.01). The relative survival of elderly patients was worse compared with that of younger patients (P<0.001). CONCLUSION: Melanoma incidence increases more rapidly for elderly than for younger patients and the decline in BT is less prominent among elderly patients than among young patients. Campaigns in the Netherlands should focus more on early melanoma detection in the elderly.