Parameter estimates for invasive breast cancer progression in the Canadian
National Breast Screening Study.
Author(s): Taghipour S(1), Banjevic D, Miller AB, Montgomery N, Jardine AK, Harvey BJ.
Affiliation(s): Author information:
(1)Department of Mechanical and Industrial Engineering, Ryerson University,
Toronto, ON M5B 2K3, Canada. sharareh@ryerson.ca or
Publication date & source: 2013, Br J Cancer. , 108(3):542-8
BACKGROUND: The aim of screening is to detect a cancer in the preclinical state.
However, a false-positive or a false-negative test result is a real possibility.
METHODS: We describe invasive breast cancer progression in the Canadian National
Breast Screening Study and construct progression models with and without
covariates. The effect of risk factors on transition intensities and
false-negative probability is investigated. We estimate the transition rates, the
sojourn time and sensitivity of diagnostic tests for women aged 40-49 and 50-59.
RESULTS: Although younger women have a slower transition rate from healthy state
to preclinical, their screen-detected tumour becomes evident sooner. Women aged
50-59 have a higher mortality rate compared with younger women. The mean sojourn
times for women aged 40-49 and 50-59 are 2.5 years (95% CI: 1.7, 3.8) and 3.0
years (95% CI: 2.1, 4.3), respectively. Sensitivity of diagnostic procedures for
older women is estimated to be 0.75 (95% CI: 0.55, 0.88), while women aged 40-49
have a lower sensitivity (0.61, 95% CI: 0.42, 0.77). Age is the only factor that
affects the false-negative probability. For women aged 40-49, 'age at entry',
'history of breast disease' and 'families with breast cancer' are found to be
significant for some of the transition rates. For the age-group 50-59, 'age at
entry', 'history of breast disease', 'menstruation length' and 'number of live
births' are found to affect the transition rates.
CONCLUSION: Modelling and estimating the parameters of cancer progression are
essential steps towards evaluating the effectiveness of screening policies. The
parameters include the transition rates, the preclinical sojourn time, the
sensitivity, and the effect of different risk factors on cancer progression.
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