Lung cancer is the deadliest cancer in China, responsible for more deaths than any other malignancy. In 2022, approximately 1.06 million new cases were diagnosed and over 730,000 people died from the disease, representing 22% of all cancer cases and 28.5% of all cancer deaths. Despite improvements in air quality, rising smoking rates and an aging population mean the burden is expected to grow in coming decades.
The stage at which lung cancer is detected is the single most important factor determining survival. Patients diagnosed at Stage I have a 5-year survival rate of around 82%, yet fewer than 20% of Chinese lung cancer patients are diagnosed at this early stage. Overall, China's 5-year lung cancer survival rate improved only modestly from 16.1% to 19.7% between 2003-2005 and 2012-2015, largely because most patients present with advanced-stage disease.
Low-dose computed tomography (LDCT) is the only proven method to reduce lung cancer deaths through screening. Major trials including the US National Lung Screening Trial (NLST) and the European NELSON trial have demonstrated that LDCT screening can reduce lung cancer mortality by 20-31% by detecting cancers earlier. China has been progressively expanding LDCT screening programs since 2009, and age-standardized 5-year survival has risen to 28.7% in 2019-2021.
This paper presents the 2025 revision of China's national LDCT lung cancer screening guideline, updating the previous 2023 version. The revision was developed by a multidisciplinary expert panel spanning thoracic surgery, medical oncology, radiology, pathology, and epidemiology, incorporating both the latest international evidence and the unique epidemiological characteristics of lung cancer in China.
The 2025 guideline recommends LDCT screening for individuals aged 50 to 80 who meet at least one additional risk criterion. The lower age threshold of 50 was retained (rather than lowering to 40 or 45 as some other guidelines suggest) because age-specific incidence data show that lung cancer rates in younger Chinese adults are considerably lower than the all-age average, and younger patients carry a higher risk of overdiagnosis.
Smoking history remains the primary risk factor for screening eligibility. Individuals who have smoked 20 or more pack-years (packs per day multiplied by years of smoking) qualify, as do those with 20 or more years of passive smoke exposure. Former smokers who quit within the last 5 years remain eligible; those who have abstained for more than 5 years may be advised to stop screening, reflecting the gradual reduction in risk after cessation.
Occupational carcinogen exposure is now more precisely defined. The previous guideline vaguely referenced 'long-term occupational exposure' without specifying duration. The 2025 update clarifies that cumulative exposure to recognized lung carcinogens (including radon, arsenic, beryllium, chromium, asbestos, silica, coke oven emissions, and coal smoke) of 5 or more years qualifies for screening. Individuals with high-intensity exposures qualify at 1 or more years.
A new stopping criterion has been added for the upper age boundary. Rather than using a rigid cutoff age, the guideline now recommends individualized assessment. If annual screening reveals that a participant's health status cannot tolerate potential lung cancer surgery, or if they develop a severe life-threatening illness, discontinuation of LDCT screening is recommended regardless of age. Family history combined with smoking also remains a qualifying criterion.
The guideline shifts from a 'lowest dose possible' philosophy to a 'right dose' philosophy. Rather than simply minimizing radiation exposure, the updated approach balances three competing considerations: the ALARA principle (as low as reasonably achievable), safety (ASARA), and diagnostic benefit (AHARA). Doses that are too low compromise image quality and can necessitate repeat scans - paradoxically increasing total patient exposure.
Specific scan parameters are calibrated to patient body size using BMI. For individuals with BMI of 30 or below, the recommended radiation dose is 0.2 mSv or less. For larger individuals with BMI above 30, doses up to 0.5 mSv are recommended. When equipment cannot achieve the lower threshold, slightly higher doses remain acceptable as long as they stay within the low-dose standard, with maximum values of 1.0 and 1.5 mSv for smaller and larger patients respectively.
Image reconstruction uses thin-slice techniques to improve nodule detection and characterization. Reconstructed slice thickness of 0.625 to 1.250 mm is recommended, with 20-30% inter-slice overlap to facilitate computer-aided detection (CAD) and volumetric analysis. Full lung coverage from apex to the costophrenic angles is performed in a single breath-hold at maximum inhalation.
Advanced image processing methods are recommended for suspicious lesions. For ground-glass nodules that may represent early lung cancer, multiplanar reformation (MPR), maximum intensity projection (MIP), and curved planar reformation (CPR) techniques help visualize internal vascular structures, nodule margins, and nearby vessel displacement. CAD software combined with human radiologist review is specifically recommended to improve nodule detection rates.
The 2025 guideline raises the threshold for classifying a nodule as 'positive' at baseline screening. Previously, solid nodules or the solid components of part-solid nodules with an average diameter of 5 mm or larger were considered positive. The new threshold is 6 mm average diameter. Non-solid nodules remain positive at 8 mm or larger. This change is expected to reduce false-positive rates by up to 36.8% - dramatically reducing unnecessary follow-up - while causing very little delay (approximately 1.5%) in diagnosing actual cancers.
Mean diameter replaces maximum diameter as the standard measurement metric. Research has shown that mean diameter more accurately distinguishes malignant from benign nodules than maximum diameter. For part-solid nodules, the measurement now focuses specifically on the mean diameter of the solid component rather than the overall nodule.
Follow-up intervals for positive nodules at baseline have been shortened and made more flexible. Solid or part-solid nodules with mean diameter 6-15 mm now require follow-up CT in 3-6 months (previously 6 months). Non-solid nodules in the 8-15 mm range are rescanned at 6 months. Nodules 15 mm or larger prompt either immediate multidisciplinary team (MDT) review or a 2-3 week course of anti-inflammatory treatment followed by reassessment at 1 month.
Annual screening nodule management follows a similar logic. Newly appearing non-calcified nodules detected at annual screening require a 6-month follow-up scan. If a previously identified nodule shows clear growth or significant increase in its solid component, immediate multidisciplinary treatment is initiated. Nodules that are stable or shrinking return to the standard annual schedule.
When LDCT raises suspicion of lung cancer, a structured multidisciplinary approach takes over. Lesions highly suspicious for lung cancer prompt review by a panel including senior thoracic surgeons, medical oncologists, pulmonologists, and radiologists. For patients suitable for surgery, surgical resection is the strongly preferred first-line intervention. The MDT framework ensures each case is evaluated from multiple clinical perspectives before a treatment path is chosen.
Airway lesions detected on LDCT are evaluated with bronchoscopy. Suspected tracheal or bronchial abnormalities lead to fiberoptic bronchoscopy. If the bronchoscopic examination confirms malignancy and surgery is feasible, surgery-centered MDT treatment is initiated. If bronchoscopy is negative, the patient returns to the standard annual screening schedule.
For patients who cannot tolerate surgery, tissue diagnosis is still obtained through minimally invasive methods. Bronchial brushing, biopsy, transbronchial mediastinal lymph node biopsy, or percutaneous lung biopsy may be performed depending on the case. Critically, the guideline now recommends that all tissue samples from suspected lung cancers undergo next-generation sequencing (NGS) to identify targetable genetic mutations, enabling personalized molecularly targeted therapy.
Screening intervals can be extended for consistently negative screeners. There is no strong biological reason why every eligible individual needs annual scans indefinitely. The guideline recommends pausing screening for 2 years for individuals who have had two consecutive negative annual LDCT results, reducing cost and radiation burden. Those with positive results maintain the annual frequency.
Overdiagnosis - detecting cancers that would never have caused symptoms or death - is a serious concern in LDCT screening. The NLST trial found that most overdiagnosed lung cancers were early adenocarcinomas arising from subsolid (ground-glass) nodules, and that overdiagnosis was more common in older women and Asian populations. Research in China specifically has found rising early-stage lung cancer rates in women without a corresponding drop in late-stage rates, a pattern consistent with overdiagnosis.
Active surveillance rather than immediate surgery is safe for pure ground-glass (non-solid) nodules. A 10-year follow-up Chinese study found no significant difference in survival between CT surveillance and immediate surgery for non-solid nodules, whether or not they grew during follow-up. This supports a conservative approach: continue monitoring until solid components appear before considering surgery, particularly in younger women where overdiagnosis risk is highest.
China-specific lung cancer risk prediction models are being developed and validated. Most global risk models were built from predominantly smoker populations in Western countries and do not fully capture Chinese epidemiology, where never-smokers represent a substantial fraction of lung cancer patients. Models incorporating both smokers and non-smokers are being constructed using large Chinese prospective cohorts, though the guideline notes that more prospective validation is needed before these tools can support population-level screening decisions.
Emerging technologies including AI, radiomics, and molecular biomarkers are poised to transform lung cancer screening. These tools hold promise for refining high-risk group selection, personalizing screening intervals, and improving the characterization of positive nodules. The guideline identifies the transition toward 'precision screening' as a key direction for future development, aiming to make screening more individualized and more efficient across China's diverse regions.
The 2025 guideline places unprecedented emphasis on shared decision-making at every stage of the screening process. Rather than treating screening as a purely medical intervention administered to patients, the guideline recommends that informed consent and collaborative decision-making between clinicians and participants be integrated into high-risk group identification, choice of screening interval, and management of detected nodules. This is particularly important for nodules with substantial uncertainty about their clinical significance.
Smoking cessation is highlighted as the most fundamental strategy for reducing lung cancer risk. The guideline explicitly states that quitting smoking is the single most effective action any smoker can take, and recommends that lung cancer screening programs be integrated with structured smoking cessation support. Participation in screening provides a 'teachable moment' and the guideline advises incorporating cessation counseling throughout the entire screening workflow.
In summary, the four major changes in the 2025 update are: first, clearer and more specific criteria for occupational exposure (5 years generally, 1 year for high-intensity); second, adoption of mean diameter (replacing maximum diameter) as the standard nodule measurement; third, raising the baseline positive solid nodule threshold from 5 mm to 6 mm and shortening positive nodule follow-up from 6 months to 3-6 months; and fourth, embedding informed consent and shared decision-making throughout all three key screening steps.
Together, these changes aim to make China's LDCT screening program simultaneously more effective and less harmful. By targeting the right populations more precisely, measuring nodules more accurately, reducing unnecessary follow-up through a higher positivity threshold, and empowering patients through shared decision-making, the 2025 guideline seeks to improve early lung cancer detection while minimizing overdiagnosis, false alarms, and unnecessary procedures across China's large and diverse population.