BACKGROUND-AIM:
Educational inequalities in both tobacco smoking behaviour and cancer mortality persist across Europe, yet the extent to which inequalities in smoking contribute to cancer mortality remains underexplored. Conventional indicators such as smoking prevalence do not reflect the duration or intensity of smoking. Lifetime smoking exposure indicators such as pack-years may provide a more precise estimate of cancer risk. This is particularly important for assessing educational inequalities in cancer mortality, as lower-educated groups accumulate far greater lifetime exposure. This study estimated the contribution of smoking based on pack-years and of educational inequalities in smoking to cancer mortality across 28 European countries in 2022.

METHODS:
Population attributable fractions (PAFs) for smoking were estimated using Levin’s formula, applying categorical pack-years derived from the Special Eurobarometer surveys (2017-2020; n=56201 aged ≥15), and relative risks for smoking-related cancers from published meta-analyses. These PAFs were applied to GLOBOCAN 2022 mortality data to estimate all cancer deaths by age and education level in each country and sex. Population preventable fractions (PPFs) were calculated using a counterfactual scenario in which all educational groups were assigned the lowest pack-years distribution observed within each country.

RESULTS:
An estimated 332000 cancer deaths or 22.5% (95% uncertainty interval, UI: 20.0%–25.0%) of all cancer deaths in Europe in 2022 were attributable to smoking. Men accounted for 70.4% of these deaths, and lung cancer alone represented more than 60% of smoking-attributable cancer deaths (203800; 189200–216900). Marked regional differences were observed, with the highest PAFs in Eastern Europe among men (32.6% [29.6%–35.4%]) and in Northern Europe among women (17.9% [15.5%–20.2%]). A clear educational gradient in pack-years was observed for both sexes, and a similar pattern in smoking-attributable cancer mortality was found for men. However, educational gradients were less consistent for women, with some Southern and Eastern European countries showing lower PAFs in the lower-education groups. If educational inequalities in smoking were eliminated, an estimated 58,000 cancer deaths or 4.0% (1.6%–7.2%) of all cancer deaths, could have been avoided, with the highest PPFs observed in Eastern Europe for men (5.7% [2.2%–9.9%]) and in Northern Europe for women (5.3% [2.7%–8.3%]).

CONCLUSIONS:
Tobacco smoking continues to be a major contributor to cancer mortality in Europe, accounting for nearly one in four of all cancer deaths. While educational inequalities in smoking do not fully explain smoking-related cancer deaths, educational inequalities in smoking-related cancer need to be monitored, as their contribution may grow over time. Achieving substantial reductions in smoking-related cancer deaths will require sustained population-wide declines in smoking combined with strategies and gains that ensure these benefits reach all socioeconomic groups.