“Cancer death rates rise sharply with age, and the age of the US population has increased since 1950, so we would expect cancer death rates to rise for that reason alone.
What if we adjust for the increased age of the US population?
The red line, the age-standardized rate, shows this. It shows the cancer death rate if the age structure of the US population was held constant throughout.
This shows a slight rise until 1990 and then a significant decline; rates have fallen by one-third.
This means Americans are now one-third less likely to die from cancer at the same ages as Americans in 1990.”
From Our World in Data.