title: Relationship between age and axillary lymph node involvement in women with breast cancer.
abstract: OBJECTIVE
  To study the relation between the presence of axillary lymph node (LN) involvement and age in breast cancer.
  
  
  METHODS
  The breast cancer database of the University Hospitals Leuven contains complete data on 2,227 patients with early breast cancer consecutively treated between 2000 and 2005. A multivariate piecewise logistic regression model was used to analyze LN involvement in relation to age at diagnosis. A similar analysis was then performed on a large, independent, population-based database from the Eindhoven Cancer Registry to investigate whether the effects of the Leuven model could be replicated.
  
  
  RESULTS
  We observed a piecewise effect of age. That is, women up to 70 years of age were less likely to have positive LNs with increasing age (odds ratio per 10-year increase, 0.87). In contrast, older women were more likely to have positive LNs with increasing age. However, for older women, the effect of age interacted with tumor size (P = .0044), suggesting that increasing age is associated with increased risk of LN involvement, mainly in small tumors. These findings were replicated in the Eindhoven Cancer Registry database.
  
  
  CONCLUSIONS
  Axillary LN involvement varies with age at diagnosis; its probability decreases with increasing age up to the age of approximately 70 years, but increases again thereafter. However, this increase is mainly seen in smaller tumors and suggests a different behavior of small breast cancers in older adult patients. We hypothesize that decreased immune defense mechanisms, related with aging, may play a role in earlier invasion into LNs.
authors.affiliation: Multidisciplinary Breast Centre and Department of General Medical Oncology, University Hospitals Leuven, Leuven, Belgium. hans.wildiers@uz.kuleuven.ac.be
authors.forename: Hans
authors.initials: H
authors.lastname: Wildiers
authors.forename: Ben
authors.initials: B
authors.lastname: Van Calster
authors.forename: Lonneke V
authors.initials: LV
authors.lastname: van de Poll-Franse
authors.forename: Wouter
authors.initials: W
authors.lastname: Hendrickx
authors.forename: Jo
authors.initials: J
authors.lastname: Røislien
authors.forename: Ann
authors.initials: A
authors.lastname: Smeets
authors.forename: Robert
authors.initials: R
authors.lastname: Paridaens
authors.forename: Karen
authors.initials: K
authors.lastname: Deraedt
authors.forename: Karin
authors.initials: K
authors.lastname: Leunen
authors.forename: Caroline
authors.initials: C
authors.lastname: Weltens
authors.forename: Sabine
authors.initials: S
authors.lastname: Van Huffel
authors.forename: Marie-Rose
authors.initials: MR
authors.lastname: Christiaens
authors.forename: Patrick
authors.initials: P
authors.lastname: Neven
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008875:Middle Aged; D015233:Models, Statistical; D012044:Regression Analysis