Tobacco Smoking and Lung Cancer Risk After Negative Baseline Low-Dose Computed Tomography Findings.

Area of Science:

• Oncology
• Pulmonology
• Epidemiology

Background:

• Lung cancer (LC) is a leading cause of cancer mortality globally, with smoking as the primary risk factor.
• Understanding long-term LC risk after negative low-dose computed tomography (LDCT) screening is crucial for optimizing screening strategies.
• The role of smoking intensity in stratifying risk post-LDCT requires further investigation.

Purpose of the Study:

• To assess the association between tobacco smoking and long-term LC risk in individuals with negative baseline LDCT findings.
• To inform the development of evidence-based, personalized lung cancer screening intervals.

Main Methods:

• A population-based, prospective cohort study involving over 30,000 participants aged 40-74 years.
• Baseline LDCT screening results were negative; participants were followed for LC incidence.
• Smoking status, pack-years, and time since quitting were analyzed using Kaplan-Meier and Cox regression models.

Main Results:

• Smokers had a significantly higher LC risk (AHR, 2.73) compared to never-smokers, particularly those with ≥20 pack-years.
• Elevated LC risk became statistically significant from 3 years post-LDCT screening onwards.
• A nonlinear dose-response relationship was observed, with risk increasing substantially around 20 pack-years; females showed higher susceptibility.

Conclusions:

• Smokers with initially negative LDCT findings face a substantial, long-term elevated risk of lung cancer.
• The increased risk becomes significant after two years, supporting potential adjustments to initial screening intervals.
• Personalized long-term monitoring strategies based on individual smoking history are recommended for optimizing lung cancer screening.