The global landscape of cancer burden attributable to tobacco smoking in 2022: a population-based systematic analysis

Background: Tobacco smoking is the most modifiable risk factor significantly contributing to the global cancer burden. Quantification of tobacco smoking-related cancer burden is essential for guiding future cancer prevention and control policy development. Methods: We used smoking prevalence data obtained from national surveys and relative risks for smoking-associated cancers extracted from high-quality published studies to calculate population attributable fractions (PAFs). We then aggregated PAFs and cancer incidence and mortality data from GLOBOCAN 2022 to estimate age-standardized incidence and mortality rates (ASIRs and ASMRs) attributable to smoking. We also compared cancer ASIRs and ASMRs between never-smokers and smokers. Findings: In 2022, estimates indicated that globally, 2,723,853 new cancer cases and 1,800,642 cancer-related deaths among individuals aged 20 years and above could be attributed to tobacco smoking, corresponding to PAFs of 14.76% (95% CI: 11.90%-17.17%) and 18.84% (95% CI: 15.22%-21.88%), respectively. Overall, males demonstrated substantially higher PAFs than females (incidence: 23.52% vs. 5.66%; mortality: 27.93% vs. 7.40%). However, for males, the highest PAF was observed in regions with a high Human Development Index (HDI), whereas for females, it peaked in regions with a very high HDI. Laryngeal exhibited the highest PAFs, followed by lung, bladder, esophageal, and oral cavity & pharyngeal cancers. However, lung cancer accounted for the largest proportion of smoking-related cancer cases (males 43.30%; females 49.97%) and deaths (males 50.04%; females 55.07%) worldwide. In higher-HDI regions, lung cancer contributed to nearly half of the smoking-related cancer burden (ranging from 45.08% to 63.25% across sexes for cases and deaths). Conversely, in lower-HDI regions, the burden was predominantly driven by oral cavity & pharyngeal, esophageal, and cervical cancers. In Eastern Asia, while the ASIRs and ASMRs of lung cancer among smokers were not globally the highest, the ASIRs (males: 39.04 per 100,000; females: 43.67 per 100,000) and ASMRs (males: 28.92 per 100,000; females: 20.86 per 100,000) among never-smokers in this region exceeded those in other geographical areas. Interpretation: Future efforts must therefore integrate aggressive, context-specific tobacco control into the core of cancer prevention strategies while prioritizing research into the unique risk factors driving lung cancer among never-smokers, particularly in high-burden populations such as Asian females. Funding: Capital's Funds for Health Improvement and Research (CFH2024-2G-40214), the CAMS Innovation Fund for Medical Sciences (2021-I2M-1-011), National High Level Hospital Clinical Research Funding (2025-LYZX-R-A03), and 2023 Special Survey on Science and Technology Basic Resources (2023FY100605).