Correcting for lead time and length bias in estimating the effect of screen detection on cancer survival

Am J Epidemiol. 2008 Jul 1;168(1):98-104. doi: 10.1093/aje/kwn120. Epub 2008 May 25.


Determination of survival time among persons with screen-detected cancer is subject to lead time and length biases. The authors propose a simple correction for lead time, assuming an exponential distribution of the preclinical screen-detectable period. Assuming two latent categories of tumors, one of which is more prone to screen detection and correspondingly less prone to death from the cancer in question, the authors have developed a strategy of sensitivity analysis for various magnitudes of length bias. Here they demonstrate these methods using a series of 25,962 breast cancer cases (1988-2004) from the West Midlands, United Kingdom.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Bias*
  • Breast Neoplasms / diagnosis
  • Breast Neoplasms / epidemiology*
  • Breast Neoplasms / mortality
  • Confidence Intervals
  • Female
  • Humans
  • Mass Screening
  • Middle Aged
  • Models, Statistical*
  • Sensitivity and Specificity
  • Time Factors
  • United Kingdom / epidemiology