Paul Holmström

Multiple primary melanomas: A common occurrence in Western Sweden

Patients diagnosed with a single primary cutaneous melanoma are at increased risk of developing multiple primary melanomas. The aim of this study is to describe the epidemiology of multiple primary melanomas (invasive and in situ) in Western Sweden. Data from the Swedish Melanoma Registry from 1990 to 2013 revealed that 898 patients (7.4%) developed 2,037 multiple primary lesions and 11,254 patients developed single lesions. The proportion of subsequent lesions that were melanoma in situ was 47%, compared with 26% of first melanomas (p < 0.0001).The median and mean time to diagnosis of a subsequent melanoma was 38 and 58 months (95% confidence interval (CI), 53-62 months). In total, 49% of subsequent melanomas were detected within 3 years. Patients and physicians should be aware of the high proportion of multiple primary melanomas in Western Sweden, especially during the first years of follow-up.

Modelling the Future: System Dynamics in the Cutaneous Malignant Melanoma Care Pathway.

Incidence rates for cutaneous malignant melanoma are increasing worldwide. Estimates of the future number of melanoma cases are important for strategic planning of the care pathway. The aim of this study was to use system dynamics modelling to evaluate the long-term effects of changes in incidence, population growth and preventive interventions. Historical data on invasive melanoma cases in Western Sweden from 1990 to 2006 were obtained. Using computer simulation software, a model estimating the accumulated number of melanoma cases for 2014 to 2023 was developed. Five future scenarios were designed: stable incidence, business-as-usual, 25% reduced patients delay, 50% reduced doctors delay, and a combination of the last two, called improved overall secondary prevention. After 10 years, improved overall secondary prevention would have resulted in a 42% decrease in melanomas > 4 mm and a 10% increase in melanomas ≤ 1 mm, compared with business-as-usual. System dynamics is a valuable tool, which can help policymakers choose the preventive interventions with the greatest impact.