pack-year history
A standardized measure of cigarette smoking exposure calculated by multiplying packs smoked per day by years of smoking.
Full Definition
A quantitative method for expressing cumulative cigarette smoking exposure, calculated by multiplying the average number of cigarette packs smoked per day by the number of years of smoking. This standardized measurement is crucial for determining eligibility for lung cancer screening programs, which typically require a minimum of 20 or 30 pack-year smoking history. For example, smoking one pack per day for 30 years equals 30 pack-years, as does smoking two packs per day for 15 years. This metric allows for consistent risk assessment and screening criteria application across diverse patient populations.
Usage
Usage note: Always hyphenate when used as a compound modifier; use 'pack-years' as the noun form.
In Context
- "The patient's 40 pack-year history of smoking qualifies him for annual lung cancer screening with low-dose CT." — Screening eligibility assessment
- "Lung cancer screening guidelines require a minimum 20 pack-year history and current smoking or cessation within 15 years." — Clinical protocol