Background
Worldwide, lung cancer is the most common cancer diagnosis in men and the second most common cancer in women, and the leading cause of cancer death. In May 2025, the World Health Organization (WHO) adopted a resolution to advance integrated lung health policies globally, including access to screening. Lung cancer screening is currently being evaluated by the International Agency for Research on Cancer (IARC) Handbooks program. The IARC Handbooks Programme, started in 1995, provides reviews and evaluations of the body of evidence on effects of different primary or secondary cancer prevention measures.

Objectives
Handbook volume 21 will provide comprehensive reviews and consensus evaluations of the available evidence on the efficacy, effectiveness, and harms of different methods for lung cancer screening.

Methods
Each volume of the IARC Handbooks is produced by an international Working Group of experts selected through a transparent process that includes public calls, declarations of interests, and careful conflict-of-interest management. The group meets to peer-review evidence, reach consensus evaluations, and jointly produce the final volume, which is checked, edited, and published by IARC. The development process of a Handbook follows detailed guidelines that are described in the Preambles publicly available (https://handbooks.iarc.fr/).
A Scoping meeting was held in Lyon (France) in April 2025 involving five international scientists without conflict of interest and seven IARC scientists. During the meeting, the panel discussed the topics to be included and developed a preliminary outline for the Handbook.
IARC conveyed a working group (WG) of 23 international independent experts selected based on their publications and without conflict of interest and an invited specialist (scientist with expert knowledge but conflict of interest who provide technical expertise on specific aspects of the topic). Experts were assigned to specific subgroups responsible for the content of different handbook sections. The IARC secretariat coordinating the development of the Handbook is composed of eight scientists. The IARC secretariat performed the preliminary searches of the literature and the WG members drafted subsections of the Handbook.
During remote subgroup meetings, each subgroup discussed and revised handbook section drafts and made preliminary evaluations of the body of evidence. During an upcoming onsite plenary meeting, drafts will be finalised and the final evaluation of the body of evidence regarding different screening methods will be performed.

Results
The evidence on benefits and harms as well as cost-effectiveness of lung cancer screening with chest X-ray and low dose computed tomography (LDCT) will be presented and evaluations about efficacy, effectiveness, and harms will be made.
In addition, the Handbook will describe delivery of lung cancer screening and will assess interventions aiming to increase participation in screening and smoking cessation interventions integrated within lung cancer screening programmes.
The body of evidence regarding potential emerging technologies in lung cancer screening will be also reviewed by the WG as part of the Handbook.
 
Conclusions/Implications
The results of the Handbook are important for policy makers and will support the implementation of the WHO resolution on lung health.