title: Clinicopathological differences between interval and screen-detected breast cancers diagnosed within a screening programme in Northern Portugal.
abstract: OBJECTIVE
  To evaluate clinicopathological differences between screen-detected (SD) and interval (IC) breast cancers diagnosed in women enrolled in an organized breast screening programme in 2000--2007.
  
  
  METHODS
  Breast Cancer Screening Programme of the north region of Portugal.
  
  
  METHODS
  Using data from the screening programme and from the population-based North Region Cancer Registry, SD and IC were identified. Information on screening history, age, date of diagnosis, tumour size, histological type and grade, lymph node status, tumour stage, biomarkers, and treatment was obtained from the cancer registry and from clinical and pathological reports. Association between mode of detection and these clinicopathological characteristics was estimated by unconditional logistic regression.
  
  
  RESULTS
  A total of 442 SD and 112 IC were identified in women aged 50--69. Compared with SD, IC were diagnosed in younger women (60.0 ± 5.8 years and 58.4 ± 6.0 years, respectively), were larger (tumour size >20 mm: 60.2% versus 25.1%), lobular (6.3% versus 16.1%), with a higher differentiation grade (grade 3: 17.7% versus 38.9%), had more lymph node metastases, more advanced stage, and oestrogen receptor (ER) negative (12.9% versus 29.0%) and progesterone negative, and HER2 positive. After multivariable analysis, compared with SD, IC were more likely to be larger than 20 mm, lobular, of grade 3 and negative for ER.
  
  
  CONCLUSIONS
  Our results are consistent with other studies. IC's have a more aggressive biology than SDs. Our findings did not show any unexpected pattern requiring changes to our screening procedures, but continuous identification and characterization of IC is advisable.
authors.affiliation: Institute of Biomedical Sciences Abel Salazar, University of Porto, and Epidemiology Unit, Portuguese Oncology Institute, Porto, Portugal mjbento@icbas.up.pt.
authors.forename: Maria
authors.initials: M
authors.lastname: José Bento
authors.affiliation: Institute of Biomedical Sciences Abel Salazar, University of Porto, Portugal.
authors.forename: Guilherme
authors.initials: G
authors.lastname: Gonçalves
authors.affiliation: Portuguese Cancer League - North Branch, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Aguiar
authors.affiliation: Institute of Biomedical Sciences Abel Salazar, University of Porto, Portugal.
authors.forename: Luis
authors.initials: L
authors.lastname: Antunes
authors.affiliation: Portuguese Cancer League - North Branch, Porto, Portugal.
authors.forename: Vitor
authors.initials: V
authors.lastname: Veloso
authors.affiliation: Faculty of Medicine, University of Coimbra, and Portuguese Cancer League - Centre Branch, Coimbra, Portugal.
authors.forename: Vítor
authors.initials: V
authors.lastname: Rodrigues
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D006801:Humans; D016015:Logistic Models; D008207:Lymphatic Metastasis; D008327:Mammography / Q000379:methods; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D011174:Portugal / Q000453:epidemiology; D012042:Registries; D013997:Time Factors; D014932:Women's Health Services
keywords: breast cancer; interval cancer; organized screening