06. Lung Cancer Screening

Bottom Line:

  • Anyone 55-80 years old with a 30 pack-year smoking history with smoke exposure within the last 15 years should get annual low-dose chest CT.
  • No role of chest x-ray screening.
  • Smoking cessation remain the most important intervention

Background:

  • Lung cancer is the leading cause of cancer-related death in men and women.
  • Cigarette smoking causes 85 to 90 percent of all lung cancer.
  • About 15% of US population smokes cigarettes.
  • 75% of patients present with incurable lung cancer
  • Five-year survival rates is average approximately 18%

Guidelines:

  • As of 2013, the USPSTF recommends annual LDCT scan for high-risk adults 55 to 80 years old with at least a 30 pack-year smoking history and current smoker or having quit within the past 15 years. Discontinue when patients has not smoked for 15 years or has a limited life expectancy.
  • ACS, ACCP, and AATS have similar recommendations but recommend stopping screening at age 74.

Evidence

  • Low dose chest CT LDCT) can scan the lungs in one breath hold, uses no iv contrast, and has less radiation than regular CT, but higher than CXR.
  • National Lung Cancer Screening Trial (NLST)  is the landmark trial
    • Randomized trial comparing annual screening by LDCT scanning vs CXR alone for 3 years. Total follow up of 6.5 years.
    • 53,454 participants 55-74 years of age with 30 pack –year smoking hx and were current smokers or quit within 15 years of enrollment.
    •  RCT demonstrated a 20% reduction in lung cancer death, 6.7% reduction in total mortality.
    • 39% of patients in the CT group had at least one positive scan (non-calcified nodule 4mm or greater)
    • HARMS: 75,000 CT scans, 18, 146 positive tests, 17,066 false positive tests, 673 thoracotomies/mediastinoscopies, 303 bronchoscopies, 99 needle biopsies to prevent 62 deaths from lung cancer.
    • NLST showed a need to screen of 256 people with LDCT annually for 3 years to prevent one lung cancer death over 6 years.
    • Most sites were either NCI-designated cancer centers and large academic medical centers likely to have specialists (i.e. thoracic oncologists and thoracic surgeons) so low adverse event (1.4% of CT group) may not apply in less experienced centers.
  • Large trials of CXR screening have shown no reduction in mortality even with sputum cytology.