title: Variations in prognostic factors in primary breast cancer throughout the menstrual cycle.
abstract: OBJECTIVE
  We investigated whether menstrual cycle dependent variations in prognostic factors are detectable in malignant breast tissue.
  
  
  METHODS
  Since 1977 the Danish Breast Cancer Cooperative Group has collected population-based information about primary clinical data, treatment regimens and follow-up status on Danish women with breast cancer. Information about last menstrual periods prior to surgery was obtained from files recorded at the time of admission for primary surgery. Included in this study were 1060 patients self-reported to be regularly menstruating and with a menstrual period within 6 weeks of surgery and who were operated in a single-step procedure. None of the patients were current users of exogenous hormones at the time of surgery. Variations of prognostic factors throughout the menstrual cycle were evaluated.
  
  
  RESULTS
  Overall, no significant correlation between endogenous hormone fluctuations and oestrogen receptor (ER) status and progesterone receptor (PgR) status were found. Furthermore, we observed no cycle-dependent variation for mitotic index, lymph node involvement or tumour size.
  
  
  CONCLUSIONS
  The classical prognostic factors in breast cancer did not differ significantly throughout the menstrual cycle in the present study.
authors.affiliation: Danish Breast Cancer Cooperative Group, Rigshospitalet, Copenhagen. kroman@dadlnet.dk
authors.forename: N
authors.initials: N
authors.lastname: Kroman
authors.forename: S M
authors.initials: SM
authors.lastname: Thorpe
authors.forename: J
authors.initials: J
authors.lastname: Wohlfahrt
authors.forename: K W
authors.initials: KW
authors.lastname: Andersen
authors.forename: H T
authors.initials: HT
authors.lastname: Mouridsen
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D003718:Denmark; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008597:Menstrual Cycle; D008875:Middle Aged; D008940:Mitotic Index; D011237:Predictive Value of Tests; D011379:Prognosis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone