Estimated worldwide variation and trends in incidence of lung cancer by histological subtype in 2022 and over time: a population-based study.

BACKGROUND

Lung cancer is the most common cancer worldwide, yet the current epidemiological profile of lung-cancer incidence by histological subtype is only partly understood. We aimed to assess geographical variation in incidence of lung cancer by subtype worldwide in 2022, geographical variation in adenocarcinoma incidence attributable to ambient particulate matter (PM) pollution worldwide in 2022, temporal trends in lung-cancer incidence by subtype from 1988 to 2017 in 19 countries, and generational changes.

METHODS

For this population-based study, we used data from the Global Cancer Observatory (GLOBOCAN) 2022, Cancer Incidence in Five Continents Volumes VII-XII, and members of the African Cancer Registry Network. To obtain national estimates of lung cancer in 2022 for the four main histological subtypes (ie, adenocarcinoma, squamous cell carcinoma [SCC], small-cell carcinoma, and large-cell carcinoma) by year, sex, and age group, we combined national estimates with representative, subsite-specific incidence proportions of lung cancer on the basis of recorded incidence data compiled in Cancer Incidence in Five Continents Volume XII and from members of the African Cancer Registry Network. We calculated country-specific, sex-specific, and age-specific proportions of and sex-specific and age-specific incidence rates per 100 000 people for all four histological subtypes. To account for differences in age composition between populations by country, we calculated age-standardised incidence rates (ASRs) per 100 000 people for lung cancer by subtype and sex at national and regional levels. We also quantified the burden of adenocarcinoma incidence attributable to ambient PM pollution for 179 countries in 2022. We conducted joinpoint regression and age-period-cohort analysis to assess temporal trends in ASRs in 19 countries by sex.

FINDINGS

In 2022, we estimated that there were 1 572 045 new cases of lung cancer worldwide among male individuals, of which 717 211 (45·6%) were adenocarcinoma, 461 171 (29·4%) were SCC, 180 063 (11·5%) were small-cell carcinoma, and 101 861 (6·5%) were large-cell carcinoma. In 2022, we estimated that there were 908 630 new cases of lung cancer worldwide among female individuals, of which 541 971 (59·7%) were adenocarcinoma, 155 598 (17·1%) were SCC, 87 902 (9·7%) were small-cell carcinoma, and 59 271 (6·5%) were large-cell carcinoma. Among male individuals, the highest ASRs were in east Asia for adenocarcinoma (27·12 [95% CI 27·04-27·21] per 100 000 people), east Europe for SCC (21·70 [21·51-21·89] per 100 000 people) and small-cell carcinoma (9·85 [9·72-9·98] per 100 000 people), and north Africa for large-cell carcinoma (4·33 [4·20-4·45] per 100 000 people). Among female individuals, the highest ASRs were in east Asia for adenocarcinoma (19·04 [18·97-19·11] per 100 000 people), north America for SCC (5·28 [5·21-5·35] per 100 000 people) and small-cell carcinoma (4·28 [4·21-4·35] per 100 000 people), and north Europe for large-cell carcinoma (2·87 [2·78-2·96] per 100 000 people). We estimated that 114 486 adenocarcinoma cases among male individuals and 80 378 adenocarcinoma cases among female individuals were attributable to ambient PM pollution worldwide in 2022, with ASRs of 2·35 (95% CI 2·33-2·36) per 100 000 male individuals and 1·46 (1·45-1·47) per 100 000 female individuals. Temporal trends in lung-cancer incidence by subtype and sex during 1988-2017 varied considerably across the 19 countries.

INTERPRETATION

Estimated geographical and temporal distribution of lung-cancer incidence varied across the four main subtypes worldwide. Our study highlights the need for future studies that identify possible causal factors that contribute to the changing risk patterns of lung cancer.

FUNDING

Natural Science Foundation of China Young Scientist Fund, Medical Scientific Research Foundation of Guangdong Province in China, and Young Innovative Talents Project of General Universities in Guangdong Province in China.