ABSTRACT: The Effectiveness of the Gail Model in Estimating Risk for Development of Breast Cancer in Women Under 40 Years of Age
Epidemiologic studies have provided information on risk factors for breast
cancer. Gail and associates identified five risk factors using
the Breast Cancer Detection Demonstration Project (BCDDP) population
and developed a model to calculate a composite relative risk
This model is commonly used to counsel women regarding
their risk for breast cancer and was used by the National Surgical
Adjuvant Breast Project (NSABP) for eligibility for the Breast
Cancer Prevention Trial. Because the BCDDP population was composed
almost entirely of women 40 years of age or older, our purpose
was to evaluate the effectiveness of the Gail model in estimating
the risk of breast cancer for women under 40 in the clinical
The Gail risk factors were assessed for 124 patients
under the age of 40 treated for either ductal carcinoma in situ
(DCIS) or invasive breast cancer at the Lahey Hitchcock Medical
Center between 1983 and 1995. The RR was calculated using the
For comparison, two cohorts of women under the age
of 40 were used: 107 randomly selected patients who underwent
a breast biopsy because of a benign condition and 129 nurses
from our institution who responded to a questionnaire that included
reproductive and family history information as used in the Gail
model. The RR calculated was the RR that existed at the time
of the surgical consultation for a suspicious breast lesion.
The Tarone-Ware method was used to analyze statistical significance
of differences between distribution. Contingency tables were
analyzed using Miettinen's modification of Fisher's exact test.
No differences were found between the median RR for all groups.
Only 2 of the 124 patients with breast cancer had a RR of 5 or
more (the RR required to enter the Breast Cancer Prevention Trial).
The distribution of age at menarche (AGEMEN) was the same for
No difference was found for the distribution of age
at first live birth (AGEFLB) between those with breast cancer
and those with a benign biopsy or the control group. The number
of breast biopsies (NBIOPS) was higher in patients with a benign
No difference was found in the distribution of
number of first-degree relatives with breast cancer (NUMREL).
Overall the Gail model failed to differentiate those women about
to have cancer diagnosed from two control populations. The Gail
model is not useful in identifying immediate risk of breast cancer
in women under 40 and should not be used for that purpose.
02/23/2001; The Breast
Ann's NOTE: RR means relative risk. The other special words relate to ways to verify data. Relative risk can be expressed in the same terms for things whose actual risk is completely different.
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