USPSTF recommends annual low-dose CT lung cancer screening for which group?

USPSTF recommends annual low-dose CT lung cancer screening for which group?

• A. Adults aged 60 to 85 years with a 20 pack-year history who currently smoke or quit within the past 15 years.
• B. Adults aged 40 to 70 years with a 15 pack-year history who currently smoke.
• C. Adults aged 50 to 80 years with a 20 pack-year history who currently smoke or quit within the past 15 years.
• D. All adults regardless of age or smoking history.

Answer: (C)

The main idea is that lung cancer screening with low-dose CT should be offered to people who are at substantial risk due to age and smoking history, because in that group the benefits of finding cancer early outweigh the potential harms of screening. The group that fits most clearly is adults aged 50 to 80 who have a 20 pack-year smoking history and who are current smokers or quit within the past 15 years. This threshold comes from evidence showing a mortality reduction from annual LDCT in people with at least 20 pack-years and within that age range, where the balance of benefits and harms favors screening. Why this set fits: age 50–80 targets a population with enough lifetime risk for lung cancer to make screening worthwhile. A 20 pack-year history ensures there is substantial cumulative exposure, increasing the likelihood that screening will detect cancers at a curable stage. The quit-within-15-years criterion acknowledges that risk remains elevated for many years after quitting, so recent quitters still benefit, whereas those who quit longer ago have lower short-term risk and may not gain the same net benefit. Why the other options don’t fit: starting screening at a younger age or with a lower pack-year history reduces the likelihood that screening will improve outcomes enough to outweigh harms; expanding screening to all adults regardless of smoking history ignores the risk-based approach and can lead to many unnecessary tests and procedures.

The main idea is that lung cancer screening with low-dose CT should be offered to people who are at substantial risk due to age and smoking history, because in that group the benefits of finding cancer early outweigh the potential harms of screening. The group that fits most clearly is adults aged 50 to 80 who have a 20 pack-year smoking history and who are current smokers or quit within the past 15 years. This threshold comes from evidence showing a mortality reduction from annual LDCT in people with at least 20 pack-years and within that age range, where the balance of benefits and harms favors screening.

Why this set fits: age 50–80 targets a population with enough lifetime risk for lung cancer to make screening worthwhile. A 20 pack-year history ensures there is substantial cumulative exposure, increasing the likelihood that screening will detect cancers at a curable stage. The quit-within-15-years criterion acknowledges that risk remains elevated for many years after quitting, so recent quitters still benefit, whereas those who quit longer ago have lower short-term risk and may not gain the same net benefit.

Why the other options don’t fit: starting screening at a younger age or with a lower pack-year history reduces the likelihood that screening will improve outcomes enough to outweigh harms; expanding screening to all adults regardless of smoking history ignores the risk-based approach and can lead to many unnecessary tests and procedures.