Estimating overdiagnosis in low-dose computed tomography screening for lung cancer: a cohort study

Area of Science:

• Oncology
• Radiology
• Pulmonology

Background:

• Lung cancer screening with low-dose computed tomography (LDCT) can lead to overdiagnosis and overtreatment of asymptomatic cancers.
• Volume-doubling time (VDT) is a potential metric to differentiate aggressive from indolent lung cancers detected during screening.

Purpose of the Study:

• To evaluate the utility of VDT in identifying overdiagnosed lung cancer cases detected through LDCT screening.
• To assess the relationship between VDT and lung cancer aggressiveness and mortality.

Main Methods:

• Retrospective analysis of VDT in a prospective LDCT lung cancer screening cohort.
• VDT was calculated for 175 patients with primary lung cancer and categorized as fast-growing (<400 days), slow-growing (400-599 days), or indolent (≥600 days).

Main Results:

• Of 120 subsequently detected cancers, 15.8% were new and fast-growing, while 84.2% were progressive.
• Lung cancer-specific mortality was significantly higher in patients with new, fast-growing cancers (9.2% per year) compared to slow-growing or indolent cancers (0.9% per year).
• A substantial proportion of incident lung cancers (approximately 25%) were classified as slow-growing or indolent.

Conclusions:

• Slow-growing or indolent lung cancers constitute a significant portion of screen-detected cases and may represent overdiagnosis.
• Minimally invasive treatments should be explored for slow-growing or indolent lung cancers to reduce overtreatment.
• VDT estimation, particularly for new cancers, has limitations due to reliance on single measurements and assumptions.