Assessment of the accuracy of the Gail model in women with atypical hyperplasia.
OBJECTIVE
An accurate estimate of a woman's breast cancer risk is essential for optimal patient counseling and management. Women with biopsy-confirmed atypical hyperplasia of the breast (atypia) are at high risk for breast cancer. The Gail model is widely used in these women, but has not been validated in them.


METHODS
Women with atypia were identified from the Mayo Benign Breast Disease (BBD) cohort (1967 to 1991). Their risk factors for breast cancer were obtained, and the Gail model was used to predict 5-year-and follow-up-specific risks for each woman. The predicted and observed numbers of breast cancers were compared, and the concordance between individual risk levels and outcomes was computed.


RESULTS
Of the 9,376 women in the BBD cohort, 331 women had atypia (3.5%). At a mean follow-up of 13.7 years, 58 of 331 (17.5%) patients had developed invasive breast cancer, 1.66 times more than the 34.9 predicted by the Gail model (95% CI, 1.29 to 2.15; P < .001). For individual women, the concordance between predicted and observed outcomes was low, with a concordance statistic of 0.50 (95% CI, 0.44 to 0.55).


CONCLUSIONS
The Gail model significantly underestimates the risk of breast cancer in women with atypia. Its ability to discriminate women with atypia into those who did and did not develop breast cancer is limited. Health care professionals should be cautious when using the Gail model to counsel individual patients with atypia.
Division of Biostatistics, Medical Oncology, General Surgery, Internal Medicine, Epidemiology, and Anatomic Pathology, Mayo Clinic, Rochester, MN 55905, USA.
V Shane
VS
Pankratz
Lynn C
LC
Hartmann
Amy C
AC
Degnim
Robert A
RA
Vierkant
Karthik
K
Ghosh
Celine M
CM
Vachon
Marlene H
MH
Frost
Shaun D
SD
Maloney
Carol
C
Reynolds
Judy C
JC
Boughey
D000293:Adolescent; D000328:Adult; D000368:Aged; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D006965:Hyperplasia; D008875:Middle Aged; D015233:Models, Statistical; D011230:Precancerous Conditions / Q000473:pathology; D018570:Risk Assessment; D012307:Risk Factors; D055815:Young Adult