title: A comparison of clinical-pathological characteristics between symptomatic and interval breast cancer.
abstract: BACKGROUND
  An association between interval breast cancers (cancer detected after a normal mammogram and before the next scheduled mammogram) and tumour aggressiveness has been postulated which may reflect their relatively poor overall prognosis. The aim of this study was to evaluate known prognostic features of screen detected breast cancers compared to interval breast cancers.
  
  
  METHODS
  Patients diagnosed with breast cancer between January 2010 and 2013 at a single unit of the National Breast Screening Program (NBSP) in Ireland and those between the ages of 50 and 65 diagnosed at a symptomatic breast clinic were included in the study. Patients who had not had a screening mammogram within the proceeding two years or had a previous history of breast cancer were excluded. Data were retrospectively collected on patient demographics, tumour type, grade, hormone receptor status and stage of disease at presentation.
  
  
  RESULTS
  There were 915 patients included in the study, with 92% (n = 844) diagnosed through the NBSP. Ductal carcinoma in-situ accounted for 19% (n = 160) of screen-detected breast cancers but only 2.8% of interval cancers (p < 0.05). The most common type of invasive cancer was invasive ductal carcinoma. Tumour grade was significantly higher in interval breast cancers (p < 0.05). Interval cancers were identified at a significantly higher stage (Stage 1 versus 2; p < 0.001) than screen-detected cancers. Interval breast cancers were less likely to be ER positive (76% versus 81%; p < 0.05) and significantly more likely to over-express HER2 (20% vs 10%, p < 0.05) than screen-detected cancers.
  
  
  CONCLUSIONS
  This study highlights the fact that interval cancers appear to have a number of adverse prognostic markers for overall breast cancer survival when compared to women with screen-detected breast cancers. Interval cancers were more likely to be invasive, of a higher grade and stage and with a greater predominance of HER2 and triple negative molecular subtypes. Therefore this heterogeneous group of tumours may be biologically more aggressive and account disproportionately to overall breast cancer mortality.
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland. Electronic address: b_meshkat@hotmail.com.
authors.forename: B
authors.initials: B
authors.lastname: Meshkat
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: R S
authors.initials: RS
authors.lastname: Prichard
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: Z
authors.initials: Z
authors.lastname: Al-Hilli
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: G A
authors.initials: GA
authors.lastname: Bass
authors.affiliation: Department of Histopathology, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Quinn
authors.affiliation: Department of Radiology, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: A
authors.initials: A
authors.lastname: O'Doherty
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: J
authors.initials: J
authors.lastname: Rothwell
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: J
authors.initials: J
authors.lastname: Geraghty
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: D
authors.initials: D
authors.lastname: Evoy
authors.affiliation: Department of Breast Surgery, St Vincent's Healthcare Group, Elm Park, Dublin 4, Ireland.
authors.forename: E W
authors.initials: EW
authors.lastname: McDermott
mesh_terms: D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000453:epidemiology; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000175:diagnosis* / Q000453:epidemiology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000737:chemistry / Q000175:diagnosis* / Q000453:epidemiology; D055088:Early Detection of Cancer / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007494:Ireland; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D009313:National Health Programs; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases; D012189:Retrospective Studies; D063189:Symptom Assessment; D013997:Time Factors
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases
keywords: Breast surgery; Clinical-pathological characteristics of breast tumour; Interval breast cancer; Symptomatic breast cancer