title: Invasive cancers detected after breast cancer screening yielded a negative result: relationship of mammographic density to tumor prognostic factors.
abstract: OBJECTIVE
  To evaluate common breast tumor prognostic characteristics, including estrogen receptor (ER) status, grade, size, and method of detection, in relationship to mammographic density.
  
  
  METHODS
  The study involved 121 women who had negative results at both screening mammography and breast physical examination within 17 months before a diagnosis of breast cancer. Mammographic density was classified according to Breast Imaging Reporting and Data System patterns 1 through 4 (where 1 indicates a fatty breast and 4 indicates a dense breast). Axillary nodal status and tumor histologic ER status, histologic grade, size, stage, and method of detection (mammography alone, palpation alone, or both palpation and mammography) were analyzed by density category and tested for statistically significant differences across categories by using analysis of variance.
  
  
  RESULTS
  Statistically significant differences (P <.05) by density category were found for the following variables: ER positivity (15 of 15 tumors in category 1 breasts, 32 of 41 tumors in category 2 breasts, 37 of 49 tumors in category 3 breasts, and eight of 16 tumors in category 4 breasts were ER positive), occurrence of grade 1 tumors (eight, 11, 19, and four tumors in category 1, category 2, category 3, and category 4 breasts, respectively, were grade 1), mean tumor size (11.3, 13.0, 14.7, and 19.7 mm for category 1, category 2, category 3, and category 4 breasts, respectively), detection with mammography alone (13, 31, 36, and four tumors in category 1, category 2, category 3, and category 4 breasts, respectively, were detected with mammography alone), and occurrence of stage I tumors (10, 25, 28, and five tumors in category 1, category 2, category 3, and category 4 breasts, respectively, were stage I).
  
  
  CONCLUSIONS
  In women with negative results at clinical and mammographic screening within 17 months before breast tumor detection, subsequently diagnosed cancers tend to be ER negative, of higher grade, and larger in size in those with dense tissue patterns than in those with fat patterns.
authors.affiliation: Departments of Radiology and Medical Education, University of Michigan Health System, 1500 E Medical Center Dr, 2910 Taubman Center, Ann Arbor, MI 48109-0326, USA.
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Roubidoux
authors.forename: Janet E
authors.initials: JE
authors.lastname: Bailey
authors.forename: Linda A
authors.initials: LA
authors.lastname: Wray
authors.forename: Mark A
authors.initials: MA
authors.lastname: Helvie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis