Validation of a model of lung cancer risk prediction among smokers

J Natl Cancer Inst. 2006 May 3;98(9):637-40. doi: 10.1093/jnci/djj163.

Abstract

The Bach model was developed to predict the absolute 10-year risk of developing lung cancer among smokers by use of participants in the Carotene and Retinol Efficacy Trial of lung cancer prevention. We assessed the validity of the Bach model among 6239 smokers from the placebo arm of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. The expected numbers of lung cancer cases and deaths without lung cancer were calculated from the Bach model and compared with the observed numbers of corresponding events over 10 years. We found that the risk model slightly underestimated the observed lung cancer risk (number of lung cancers expected/number observed = 0.89, 95% confidence interval [CI] = 0.80 to 0.99) over 10 years. The competing risk portion of the model substantially underestimated risk of non-lung cancer mortality (number of non-lung cancer deaths expected/number observed = 0.61, 95% CI = 0.57 to 0.64) over 10 years. The age-specific concordance indices for 10-year predictions were 0.77 (95% CI = 0.70 to 0.84), 0.59 (95% CI = 0.53 to 0.65), 0.62 (95% CI = 0.57 to 0.67), and 0.57 (95% CI = 0.49 to 0.67) for the age groups 50-54, 55-59, 60-64, and 65-69 years, respectively. Periodic radiographic screening in the ATBC Study may explain why slightly more cancers were observed than expected from the Bach model.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Age Distribution
  • Age Factors
  • Aged
  • Anticarcinogenic Agents / administration & dosage
  • Clinical Trials as Topic
  • Confidence Intervals
  • Humans
  • Incidence
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / epidemiology*
  • Lung Neoplasms / etiology*
  • Lung Neoplasms / mortality
  • Lung Neoplasms / prevention & control
  • Mass Chest X-Ray
  • Middle Aged
  • Models, Statistical*
  • Predictive Value of Tests
  • Reproducibility of Results
  • Risk Assessment
  • Risk Factors
  • Smoking / adverse effects*
  • United States / epidemiology
  • alpha-Tocopherol / administration & dosage
  • beta Carotene / administration & dosage

Substances

  • Anticarcinogenic Agents
  • beta Carotene
  • alpha-Tocopherol