Cancer mortality rates have declined but inequalities in rates have widened.
Relative inequalities are dominated by inequalities in lung cancer mortality.
There is also a contribution from liver and head and neck cancers (men).
And from breast cancer (women), stomach and cervical cancer (younger women).
Understanding these patterns is important in reducing preventable cancer deaths.
In many high-income countries cancer mortality rates have declined, however, socioeconomic inequalities in cancer mortality have widened over time with those in the most deprived areas bearing the greatest burden. Less is known about the contribution of specific cancers to inequalities in total cancer mortality.
Using high-quality routinely collected population and mortality records we examine long-term trends in cancer mortality rates in Scotland by age group, sex, and area deprivation. We use the decomposed slope and relative indices of inequality to identify the specific cancers that contribute most to absolute and relative inequalities, respectively, in total cancer mortality.
Cancer mortality rates fell by 24 % for males and 10 % for females over the last 35 years; declining across all age groups except females aged 75+ where rates rose by 14 %. Lung cancer remains the most common cause of cancer death. Mortality rates of lung cancer have more than halved for males since 1981, while rates among females have almost doubled over the same period.
Current relative inequalities in total cancer mortality are dominated by inequalities in lung cancer mortality, but with contributions from other cancer sites including liver, and head and neck (males); and breast (females), stomach and cervical (younger females). An understanding of which cancer sites contribute most to inequalities in total cancer mortality is crucial for improving cancer health and care, and for reducing preventable cancer deaths.
Cancer is the second leading cause of death worldwide with approximately one in six deaths globally [ ], and one in four deaths in Europe and in the UK, due to cancer. It is the leading cause of death in Scotland (population of approximately 5.4 million) with 16,250 cancer deaths recorded in 2018 (27 % of total deaths). Cancer mortality rates have fallen by 24 % for males and by 10 % for females since 1981; small declines compared to those observed for other major causes of death, such as ischaemic heart disease and stroke [ ].
Cancer mortality rates in Scotland are higher than the UK as a whole for all cancers [ ] and for several specific cancers [ ]. Lung cancer mortality rates, in particular, are around a third higher than the UK average [ ]. While current male lung cancer mortality rates in Scotland are comparable to European rates, rates for females in Scotland are more than twice the rates for females in Europe [ , ].
Describing the magnitude of social inequalities in cancer and monitoring progress in reducing social inequalities in cancer has been recommended as a priority for research [ ]. A recent publication from the International Agency for Research on Cancer (IARC) highlights the large differences in cancer incidence, survival and mortality that exists between and within countries across social groups [ ]. In Scotland, overall cancer mortality rates are currently around 74 % higher in the most deprived areas compared to the least deprived [ ], reflecting persistent inequalities in cancer incidence [ ] and cancer survival [ ].
Reducing social inequalities in total cancer mortality requires an understanding of the contribution of site-specific cancers to absolute and relative inequalities in cancer mortality. Our work examines the extent to which specific cancers contribute to current inequalities in cancer mortality in Scotland. We also look at long-term trends in cancer mortality in Scotland by age group, sex, and area deprivation using high-quality routinely collected Scottish mortality and population records.