title: The impact of the Polish mass breast cancer screening program on prognosis in the Pomeranian Province.
abstract: BACKGROUND
  Mammographic screening results in diagnosis of less advanced breast cancer (BC). A meta-analysis of randomized clinical trials confirmed that BC screening reduces mortality. In 2007, the National Breast Cancer Screening Program (NBCSP) was established in Poland with the crucial aim of reducing mortality from BC. The purpose of this study was to assess the impact of participation in the NBCSP on prognosis.
  
  
  METHODS
  A single institution, non-randomized retrospective study was undertaken. The study population comprised 643 patients with BC treated in the Department of Surgical Oncology (DSO) at the Medical University of Gdansk over a 4-year period, from 01.01.2007 until 31.12.2010. Patients were divided into two groups: group A - patients who participated in the NBCSP (n= 238, 37.0%); and group B - patients who did not participate in the NBCSP (n= 405, 63.0%).
  
  
  RESULTS
  Statistical analysis revealed that group A displayed a less advanced AJCC stage (more patients in AJCC stage I,p= 0.002), lower tumor diameter (more patients with pT1,p= 0.006, and pT < 15 mm,p= 0.008) and a lower incidence of metastases to axillary lymph nodes (more patients with pNO,p= 0.01). From 2009 to 2010 the NBCSP revealed a statistically significant benefit - significantly more patients in stage 0 + I (60.7% vs. 48.8%,p= 0.018) and with tumors pT < 15 mm (48.8% vs. 35.1%,p= 0.011) were observed in group A.
  
  
  CONCLUSIONS
  The study results revealed the beneficial impact of the NBCSP. Superior prognostic factors and favorable staging were observed in women who participated in the NBCSP.
authors.affiliation: Department of Oncological Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Woźniacki
authors.affiliation: Department of Oncological Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Jarosław
authors.initials: J
authors.lastname: Skokowski
authors.affiliation: Department of Mathematics, Uppsala University, Uppsala, Sweden.
authors.forename: Krzystof
authors.initials: K
authors.lastname: Bartoszek
authors.affiliation: Department of Oncological Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kosowska
authors.affiliation: Department of Medical Laboratory Diagnostics and Bank of Frozen Tissues and Genetic Specimens, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Leszek
authors.initials: L
authors.lastname: Kalinowski
authors.affiliation: Department of Oncological Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Jaśkiewicz
keywords: AJCC staging; breast cancer; mass screening; prognosis; prognostic factors; screening