From the Guidelines
Lung cancer screening is not recommended for nonsmoking Asian populations without specific risk factors, but those with a history of significant exposure to carcinogens, family history of lung cancer, or certain lung diseases may benefit from annual low-dose CT scans. The decision to screen should be based on individual risk factors rather than ethnicity alone, as the incidence of lung cancer in never-smoking Asians is influenced by a combination of genetic, environmental, and hormonal factors 1.
Risk Factors for Lung Cancer in Nonsmoking Asians
- Age
- Unhealthy diet
- Alcohol intake
- Chronic disease (COPD, asthma, and others)
- Social psychology
- Body fat and obesity
- Family history of lung cancer
- Significant secondhand smoke exposure
- Occupational exposures to carcinogens like radon, asbestos, or arsenic
Screening Recommendations
For nonsmoking Asians with specific risk factors, screening with low-dose CT scans may be appropriate. The China Guideline for the Screening and Early Detection of Lung Cancer recommends a screening age of 50-74 years, combined with one of the following conditions: a history of smoking at least 30 packs/year, a passive smoking history ≥ 20 years, a history of COPD, a history of occupational exposure ≥ 1 year, and first-degree relatives diagnosed with lung cancer 1.
Management and Follow-up of Lung Nodules
Lung nodules can be further divided into three types: solid nodules, part-solid nodules, and pure ground-glass nodules (GGNs). The management and follow-up recommendations for lung nodules in China are outlined in a flow chart, which recommends annual screening for patients with pure GGN < 8.0 mm or a solid/part-solid nodule < 6.0 mm, and evaluation after 3 months for patients with pure GGN between 8.0-15.0 mm or the solid component of a solid/part-solid nodule between 6.0-15.0 mm 1.
Importance of Personalized Recommendations
Anyone concerned about their lung cancer risk should consult with their healthcare provider for personalized recommendations based on their complete risk profile rather than ethnicity alone. The identification of high-risk populations is crucial to maximize socio-economic benefits and minimize screening-associated harms, such as radiation exposure and false positives 1.
From the Research
Lung Cancer Screening among Nonsmoking Asian Population
- The incidence and mortality of lung cancer are highest in Asia compared with Europe and USA, with the incidence and mortality rates being 34.4 and 28.1 per 100,000 respectively in East Asia 2.
- Family history is the most common risk factor for nonsmokers in Asia 2.
- Low-dose computed tomography (LDCT) screening is recommended once a year for patients with screening-detected abnormality and persistent exposure to risk factors, however, for high-risk heavy smokers and nonsmokers with risk factors, reassessment scans are recommended at an initial interval of 6 to 12 months 2.
- Current screening guidelines and eligibility criteria can miss more than 50% of lung cancers, and in some geographic areas, such as East Asia, a large proportion of the missed lung cancers are in never-smokers 3.
- Several known and suspected risk factors for lung cancers in never-smokers, such as exposure to secondhand smoke, occupational carcinogens, radon, air pollution, and pulmonary diseases, are well noted 3.
- Knowledge of risk factors may make possible quantification and prediction of lung cancer risk in never smokers, and it is worth considering if and how never smokers could be included in population-based screening programs 3.
- Although screening of never smokers may in the future be effectively conducted, current evidence to support widespread implementation of this practice is lacking 3.
- Risk-based lung cancer screening is an alternative approach that defines screening eligibility based on the personal risk of individuals, and numerous risk prediction models have been developed to estimate the lung cancer risk of individuals incorporating sociodemographic, smoking, and clinical risk factors associated with lung cancer 4.
- LDCT screening may be clinically effective in reducing lung cancer mortality, but there is considerable uncertainty, and there is evidence that a single round of screening could be considered cost-effective at conventional thresholds, but there is significant uncertainty about the effect on costs and the magnitude of benefits 5.