title: Influence of histology on the effectiveness of adjuvant chemotherapy in patients with hormone receptor positive invasive breast cancer.
abstract: BACKGROUND
  To investigate the effect of adjuvant chemotherapy on long term survival in addition to hormonal therapy in the systemic treatment of hormonal receptor positive breast cancer patients.
  
  
  METHODS
  All patients with primary non-metastatic hormonal receptor positive invasive lobular (mixed) (=ILC) and invasive ductal (=IDC) breast cancer operated on between 1986 and 2007 were identified from a population based cohort. Four hundred ninety-eight patients with lobular (mixed) and sixteen hundred seventeen with ductal cancer were eligible. Both groups were divided in patients receiving adjuvant hormonal treatment with or without systemic chemotherapy.
  
  
  RESULTS
  Overall survival was not statistically different in patients with ILC treated with adjuvant hormonal and chemotherapy compared to hormonal treatment alone (5-year survival 85.2% vs 82.8%, P = .68). In contrast, patients with IDC receiving adjuvant hormonal and chemotherapy had a significantly better overall survival compared to hormonal therapy alone (5-year survival rate 87.6% vs 80.8%, P < .001). In the multivariate analysis however, this significance disappeared suggesting that the data are possibly too small, too unbalanced, or influenced by other confounding factors to come to definitive conclusions.
  
  
  CONCLUSIONS
  There are good reasons to consider ductal and lobular breast cancers as different entities in future studies. Patients with hormone receptor positive ILC seem to benefit differently from additional adjuvant chemotherapy to hormonal therapy as compared with patients with IDC.
authors.affiliation: Department of Surgery, Máxima Medical Centre, PO Box 7777, 5500 MB Veldhoven, The Netherlands. wilfredtruin@hotmail.com
authors.forename: Wilfred
authors.initials: W
authors.lastname: Truin
authors.forename: Adri C
authors.initials: AC
authors.lastname: Voogd
authors.forename: Gerard
authors.initials: G
authors.lastname: Vreugdenhil
authors.forename: Maurice J C
authors.initials: MJ
authors.lastname: van der Sangen
authors.forename: Mike W P M
authors.initials: MW
authors.lastname: van Beek
authors.forename: Rudi M H
authors.initials: RM
authors.lastname: Roumen
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality; D018275:Carcinoma, Lobular / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008875:Middle Aged; D009426:Netherlands; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012042:Registries; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone