BACKGROUND AND PURPOSE:

• Previous randomized controlled trials have demonstrated the benefit of low dose computed tomography for detection of early-stage lung cancer vs chest radiography or no screening
• Real world evidence is limited
• Potter et al. (BMJ, 2022) examined the impact of low dose computed tomography screening on lung cancer outcomes

METHODS:

• Quasi-experimental study
  • Data derived from the US National Cancer Database and SEER
• Participants
  • 45 to 80 years
  • Diagnosed with non-small cell lung cancer (NSCLC) between January 2010 and December 2018
• Exposures
  • 2010 to 2013: Pre-recommendation of USPSTF lung cancer screening guideline 
  • 2014 to 2018: Post-recommendation of USPSTF screening guideline
• Study design
  • Multivariable ordinal logistic regression
  • Multivariable Cox proportional hazards modeling used to assess outcomes
• Primary outcomes
  • Annual percent change in percentage of stage 1 NSCLC diagnosed among patients aged 45 to 54 (ineligible for screening) and 55 to 80 (potentially eligible for screening)
  • Median all cause survival
  • Incidence of NSCLC
  • Year-to-year changes in likelihood of having earlier stages of disease at diagnosis
  • Changes in hazard of death

RESULTS:

• 763,474 patients
• The percentage of stage I NSCLC diagnosed among patients 55 to 80 years did not significantly increase from 2010 to 2013 but did increase from 2014 to 2018
  • From 2010 to 2013: 27.8% to 29.4%
  • From 2014 to 2018: 30.2% to 35.5%
  • Annual increase: 3.9% per year (95% CI, 3.0 to 4.8)
• The odds were higher of having one lung cancer stage lower at diagnosis during the post-recommendation period, compared with pre-recommendation
  • From 2014 to 2018: 6.2% increase in odds per year
  • Adjusted odds ratio (aOR) 1.062 (95% CI, 1.048 to 1.077); P<0.001
• Median all-cause survival of patients 55 to 80 years did not significantly increase from 2010 to 2013, but did increase from 2014 to 2018
  • From 2010 to 2013: 15.8 to 18.1 months
  • From 2014 to 2018: 19.7 to 28.2 months
  • Annual increase 11.9% per year (95% CI, 8.9 to 15.0)
• The hazard of death decreased significantly faster after 2014 vs before 2014 (P<0.001)
• By 2018, stage 1 NSCLC was the predominant diagnosis among
  • Non-Hispanic White people
  • People living in the highest income or best educated regions
• Stage IV disease at diagnosis were more commonly seen among
  • Non-White people
  • Lower income or less educated regions

CONCLUSION:

• There has been a shift towards more stage 1 NSCLC diagnoses in the US following new USPSTF lung cancer screening recommendations introduced in 2013, suggestive of more early-stage diagnoses
• Increases in the detection of early-stage lung cancer in the US from 2014 to 2018 averted an estimated 10,100 deaths
• Non-white patients and those living in lower resource areas are less likely to experience the benefits of screening recommendations as they are the most likely to have stage IV disease at diagnosis
• The authors state

Differences in the percentage of people at high risk meeting screening eligibility criteria among certain populations and the inability to support lung cancer screening programs in community settings may contribute to widening disparities in the early diagnosis and survival of patients with lung cancer in the near future if efforts to increase eligibility for screening and to increase adoption of screening are neglected

Learn More – Primary Sources:

Association of computed tomography screening with lung cancer stage shift and survival in the United States: quasi-experimental study

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