title: Breast cancer risk by extent and type of atypical hyperplasia: An update from the Nurses' Health Studies.
abstract: BACKGROUND
  Women with atypical hyperplasia (AH) on a benign breast biopsy specimen are at increased risk for the development of breast cancer. However, the relation between the type and extent of AH (atypical ductal hyperplasia [ADH] vs atypical lobular hyperplasia [ALH]) and the magnitude of the breast cancer risk is not well defined.
  
  
  METHODS
  A nested case-control study of benign breast disease and breast cancer risk was conducted. Women with breast cancer and prior benign breast biopsy findings (488 cases) were matched to women with prior benign breast biopsy findings who were free from breast cancer (1907 controls). Benign breast biopsy slides were reviewed and categorized as nonproliferative, proliferative without atypia, or AH (ADH or ALH). The number of foci of AH was also recorded.
  
  
  RESULTS
  Among women with ADH, the interrelation between the extent of atypia and breast cancer risk was not significant (odds ratio [OR] for 1 or 2 foci, 3.5; 95% confidence interval [CI], 2.2-5.6; OR for ≥3 foci, 2.7; 95% CI, 1.4-5.1; P = .41). Similarly, although the risk with ALH was higher for those with ≥3 foci than for those with <3 foci, the difference was not statistically significant (OR for 1 or 2 foci, 5.2; 95% CI, 2.7-10.0; OR for ≥3 foci, 8.0; 95% CI, 4.5-14.2; P = .19).
  
  
  CONCLUSIONS
  This analysis demonstrates that the extent of ADH or ALH does not significantly contribute to breast cancer risk. The lack of a significant dose-response relation between the extent and type of atypia and breast cancer risk suggests that it would be premature to use the extent of atypia to influence management decisions for women with ADH or ALH.
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Collins
authors.affiliation: Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston, Massachusetts.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Aroner
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.
authors.forename: James L
authors.initials: JL
authors.lastname: Connolly
authors.affiliation: Institute of Public Health, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Graham A
authors.initials: GA
authors.lastname: Colditz
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Schnitt
authors.affiliation: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.|Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts.
authors.forename: Rulla M
authors.initials: RM
authors.lastname: Tamimi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: atypical hyperplasia; benign breast disease; breast cancer