Correcting for lead time and length bias in estimating the effect of screen detection on cancer survival.
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.
Duffy
Stephen W
SW
Cancer Research UK Centre for Epidemiology, Mathematics and Statistics, Wolfson Institute for Preventive Medicine, London, United Kingdom.
Nagtegaal
Iris D
ID
Wallis
Matthew
M
Cafferty
Fay H
FH
Houssami
Nehmat
N
Warwick
Jane
J
Allgood
Prue C
PC
Kearins
Olive
O
Tappenden
Nancy
N
O'Sullivan
Emma
E
Lawrence
Gill
G
D000368:Aged; D015982:Bias; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008403:Mass Screening; D008875:Middle Aged; D015233:Models, Statistical; D012680:Sensitivity and Specificity; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology