Background: Early detection has been the historical strategy for improving outcomes in patients diagnosed with melanoma. Since the 1960s, physicians have focused on interventions to educate the public about the nature of melanoma and the importance of sun protection and regular skin cancer screening. Despite these efforts, publications have highlighted the rapid increase in melanoma incidence over the past four decades with minimal changes in the mortality rates. In fact, the recent drop in melanoma mortality has been widely attributed to the introduction of newer medications such as molecular and immune checkpoint therapies approved in the mid 2010’s. However, the impact of ongoing public efforts remains unknown. We thus set out to more closely examine the dynamics of melanoma mortality in the “pre-therapeutic era” and test the hypothesis that death rates have been unwavering. To accomplish this, we characterized and modeled mortality trends between 1969-2014 in both the U.S. and Australia.

Methods: We performed a differential time series analysis based on population-ascertained mortality rates (total, male, and female) from the United States (SEER) and Australia (Cancer Australia). To this end, we calculated the first derivative of yearly mortality rates between 1969-2014 and analyzed trends using linear regression. Melanoma mortality rates were then modeled using a second-order polynomial regression and compared to mortality trajectories of 10 other cancers.

Results: Melanoma mortality rates have been significantly decelerating since the 1970s in both the U.S. (p<0.0001) and Australia (p=0.0021). Zero acceleration occurred around 2001 (95% CI: 1996, 2008) for the U.S. and 2004 (95% CI: 1999, 2011) for Australia. The male mortality rates decelerated 3-4 times faster than females in both countries, though the absolute male mortality rates were much higher. Melanoma mortality followed a quadratic function (R2>0.9). Compared to total U.S. cancer death rates and mortality among ten other cancer types, melanoma showed a similar quadratic distribution albeit with a later inflection point (1986 vs. 2001) and broader focal width.

Conclusion: Deaths due to melanoma have been decelerating for the past five decades, reaching an inflection point around 2001 prior to the advent of modern therapies. These findings suggest that mitigating campaigns had already taken afoot in both the U.S. and Australia.