Stratification of breast cancer risk in women with atypia: a Mayo cohort study.
OBJECTIVE
Atypical hyperplasia is a well-recognized risk factor for breast cancer, conveying an approximately four-fold increased risk. Data regarding long-term absolute risk and factors for risk stratification are needed.


METHODS
Women with atypical hyperplasia in the Mayo Benign Breast Disease Cohort were identified through pathology review. Subsequent breast cancers were identified via medical records and a questionnaire. Relative risks (RRs) were estimated using standardized incidence ratios, comparing the observed number of breast cancers with those expected based on Iowa Surveillance, Epidemiology, and End Results (SEER) data. Age, histologic factors, and family history were evaluated as risk modifiers. Plots of cumulative breast cancer incidence provided estimates of risk over time.


RESULTS
With mean follow-up of 13.7 years, 66 breast cancers (19.9%) occurred among 331 women with atypia. RR of breast cancer with atypia was 3.88 (95% CI, 3.00 to 4.94). Marked elevations in risk were seen with multifocal atypia (eg, three or more foci with calcifications [RR, 10.35; 95% CI, 6.13 to 16.4]). RR was higher for younger women (< 45; RR, 6.76; 95% CI, 3.24 to 12.4). Risk was similar for atypical ductal and atypical lobular hyperplasia, and family history added no significant risk. Breast cancer risk remained elevated over 20 years, and the cumulative incidence approached 35% at 30 years.


CONCLUSIONS
Among women with atypical hyperplasia, multiple foci of atypia and the presence of histologic calcifications may indicate "very high risk" status (> 50% risk at 20 years). A positive family history does not further increase risk in women with atypia.
Degnim
Amy C
AC
Division of General Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Visscher
Daniel W
DW
Berman
Hal K
HK
Frost
Marlene H
MH
Sellers
Thomas A
TA
Vierkant
Robert A
RA
Maloney
Shaun D
SD
Pankratz
V Shane
VS
de Groen
Piet C
PC
Lingle
Wilma L
WL
Ghosh
Karthik
K
Penheiter
Lois
L
Tlsty
Thea
T
Melton
L Joseph
LJ
Reynolds
Carol A
CA
Hartmann
Lynn C
LC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001941:Breast Diseases / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology; D001943:Breast Neoplasms / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology; D015331:Cohort Studies; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia / Q000150:complications* / Q000453:epidemiology; D008875:Middle Aged; D012306:Risk; D013997:Time Factors