Differential time series analysis shows deceleration in melanoma mortality prior to the widespread use of highly effective therapies.

ABSTRACT

BACKGROUND: Although the recent drop in melanoma mortality has been attributed to the introduction of newer therapies, the impact of ongoing public efforts remains unknown. OBJECTIVE: Characterize and model melanoma mortality trends before the era of molecular and immune therapies (1969-2014) in the U.S. and Australia. METHODS: Differential time series analysis based on population-ascertained melanoma mortality rates from the U.S. and Australia. Mortality rates were modeled and compared to the trajectories of ten other cancers. RESULTS: Melanoma mortality rates have been significantly decelerating since the 1970s in both the U.S. (P < .0001) and Australia (P = .0021). Zero acceleration occurred around 2001 (95% CI 1996, 2008) for the U.S. and 2004 (95% CI 1999, 2011) for Australia. Male mortality rates decelerated 3x-4x faster than females in both countries. Melanoma mortality followed a similar quadratic function (R2 > 0.9) to 10 other cancers, albeit with a later inflection point (1986 vs 2001) and broader focal width. LIMITATIONS: Absolute mortality data used without further stratification or considering cancer incidence or covariates. CONCLUSION: Melanoma deaths have been decelerating for the past 5 decades, reaching an inflection point around 2001, suggesting that mitigating campaigns were already afoot in both the U.S. and Australia before the advent of modern therapies.