title: Younger age as a prognostic indicator in breast cancer: a cohort study.
abstract: BACKGROUND
  The debate continues as to whether younger women who present with breast cancer have a more aggressive form of disease and a worse prognosis. The objectives of this study were to determine the incidence of breast cancer in women under 40 years old and to analyse the clinicopathological characteristics and outcome compared to an older patient cohort.
  
  
  METHODS
  Data was acquired from a review of charts and the prospectively reviewed GUH Department of Surgery database. Included in the study were 276 women diagnosed with breast cancer under the age of forty and 2869 women over forty. For survival analysis each women less than 40 was matched with two women over forty for both disease stage and grade.
  
  
  RESULTS
  The proportion of women diagnosed with breast cancer under the age of forty in our cohort was 8.8%. In comparison to their older counterparts, those under forty had a higher tumour grade (p = 0.044) and stage (p = 0.046), a lower incidence of lobular tumours (p < 0.001), higher estrogen receptor negativity (p < 0.001) and higher HER2 over-expression (p = 0.002); there was no statistical difference as regards tumour size (p = 0.477). There was no significant difference in overall survival (OS) for both groups; and factors like tumour size (p = 0.026), invasion (p = 0.026) and histological type (p = 0.027), PR (p = 0.031) and HER2 (p = 0.002) status and treatment received were independent predictors of OS CONCLUSION: Breast cancer in younger women has distinct histopathological characteristics; however, this does not result in a reduced survival in this population.
authors.affiliation: Department of Surgery, National University of Ireland, Galway, Ireland. michael.kerin@nuigalway.ie
authors.forename: Elrasheid H A
authors.initials: EH
authors.lastname: Kheirelseid
authors.forename: Jennifer M E
authors.initials: JM
authors.lastname: Boggs
authors.forename: Catherine
authors.initials: C
authors.lastname: Curran
authors.forename: Ronan W
authors.initials: RW
authors.lastname: Glynn
authors.forename: Cara
authors.initials: C
authors.lastname: Dooley
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Sweeney
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kerin
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies