Geotemporal Analysis of Melanoma Incidence and Mortality Identifies Distinct Clusters of Trends within the United States Between 2001 and 2019.

The extent to which the geographic diversity of the US plays a significant role in melanoma incidence and mortality over time has not been precisely characterized. We obtained age-adjusted melanoma data for the 50 states between 2001 and 2019 from the Surveillance, Epidemiology, and End Results registry and performed hierarchical clustering (complete linkage, Euclidean space) to uncover geo-temporal trend groups over 2 decades. While there was a global increase in incidence during this time (b = +0.41, P < .0001), there were 6 distinct clusters (by absolute and Z-score) with significantly different temporal trends (analysis of covariance P < .0001). Cluster 2 states had the sharpest increase in incidence with b = +0.66, P < .0001. For mortality, the global rate decreased (b = -0.03, P = .0003) with 3 and 6 clusters by absolute and Z-scores, respectively (analysis of covariance P < .05). Cluster 1 states exhibited the smallest decline in mortality (b = -0.017, P = .008). Mortality to incidence ratios declined (b = -0.0037, P < .0001) and harbored 4 and 6 clusters by absolute and Z-score analysis, respectively (analysis of covariance P < .0001). Cluster 4 states had the lowest rate of mortality to incidence ratios decline (b = -0.003, P < .0001). These results provide an unprecedented higher dimensional view of melanoma behavior over space and time. With more refined analyses, geospatial studies can uncover local trends which can inform public health agencies to more properly allocate resources.