Table 1.

Proportion of the breast cancer advanced to the year of screening by year at which the diagnosis would have taken place in the absence of screening

Years after screenAverage lead-time of 3.2 years (λ = 0.34)Average lead-time of 4.7 years (λ = 0.22)
185%90%
260%71%
343%58%
431%47%
522%38%
616%30%
712%25%
89%20%
97%16%
105%14%
1111%
1210%
138%
147%
156%
  • NOTE: λ is the instantaneous rate in the exponential distribution of transition time from progressive preclinical screen-detectable breast cancer to symptomatic disease.