title: Postpartum breast cancer behaves differently.
abstract: OBJECTIVE
  Previous studies suggest a worse prognosis for postpartum breast cancer (PPBC) diagnosed within the first 12 months following delivery. We investigated this hypothesis in our setting through a retrospective pilot study.
  
  
  METHODS
  A retrospective multicentre paired case-control study of breast cancer patients diagnosed under age 45 from the UZ Leuven database or affiliated centres. We compared disease outcome of women with a PPBC and those without a pregnancy associated breast cancer (PABC). They were matched for the following prognostic markers: age at diagnosis, tumour type, characteristics and stage. Kaplan-Meier statistics were applied for overall and disease free survival.
  
  
  RESULTS
  53 PPBC cases were matched with 103 controls. All PPBC patients were diagnosed with an invasive ductal carcinoma. Axillary lymph nodes were involved in 56.6% of cases and 13% were primary metastasized at diagnosis. A third was triple-negative and another third was HER-2-positive.The 5-year overall survival was 60% and 84% respec-tively for PPBC cases and control group. 5-year disease free survival was respectively 53% and 68%.
  
  
  CONCLUSIONS
  We confirm that postpartum breast cancer behaves more aggressively than the matched non-PABC group. Longer follow-up and extension of the study group are necessary to confirm these findings.
authors.affiliation: Multidisciplinary Breast Centre, Department of Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium--
authors.forename: N
authors.initials: N
authors.lastname: Van den Rul
authors.affiliation: Multidisciplinary Breast Centre, Department of Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium--
authors.forename: S N
authors.initials: SN
authors.lastname: Han
authors.affiliation: Multidisciplinary Breast Centre, Department of Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium--
authors.forename: K
authors.initials: K
authors.lastname: Van Calsteren
authors.affiliation: Multidisciplinary Breast Centre, Department of Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium--
authors.forename: P
authors.initials: P
authors.lastname: Neven
authors.affiliation: Multidisciplinary Breast Centre, Department of Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium--
authors.forename: F
authors.initials: F
authors.lastname: Amant
keywords: Breast cancer; Matched case-control study; Postpartum; Prognosis
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