title: A clinicopathological study of early-stage synchronous bilateral breast cancer: a retrospective evaluation and prospective validation of potential risk factors.
abstract: BACKGROUND
  The aim of the present study was to investigate potential risk factors for synchronous bilateral breast cancer sBBC).
  
  
  METHODS
  A retrospective analysis was performed of patients diagnosed and treated with operable bilateral breast cancer (BBC) between June 2007 and December 2011. Risk factors for sBBC were evaluated in this cohort and further validated in a prospective observational validation analysis of patients between January 2012 and December 2012. Patients treated with operable unilateral breast cancer during the same period were used as a control group.
  
  
  RESULTS
  A total of 11,247 patients with primary breast cancer underwent operations at the Fudan University Shanghai Cancer Center between June 2007 and December 2012. The incidence of sBBC was 1.6%. The age at diagnosis (HR = 2.4, 95% C.I.: 1.4-4.0, p = 0.001), presence of sclerosing adenosis (HR = 11.8, 95% C.I.: 5.3-26.3, p<0.001), lobular carcinoma component involvement (HR = 5.6, 95% C.I.: 2.6-12.1, p<0.001), and family history of first-degree relatives with breast cancer (HR = 2.0, 95% C.I.: 1.1-3.4, p<0.001) were independent risk factors for sBBC. A subsequent validation study failed to confirm the significance of family history. No significant difference on survival was found between patients with early-stage sBBC and control cases.
  
  
  CONCLUSIONS
  Patients with the presence of sclerosing in the affected breast, and lobular carcinoma component involvement may be at high risk for developing sBBC. This study supports the hypothesis that the host-carcinoma biological relationship, especially for the tumor microenvironment, played a critical role in the carcinogenesis of sBBC.
authors.affiliation: Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Jia-Jian
authors.initials: JJ
authors.lastname: Chen
authors.affiliation: Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Jing-Yan
authors.initials: JY
authors.lastname: Xue
authors.affiliation: Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Ultrasound, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Ya-Ling
authors.initials: YL
authors.lastname: Chen
authors.affiliation: Department of Diagnostic Radiology, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Xiao
authors.affiliation: Department of Pathology, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Yang
authors.affiliation: Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Shao
authors.affiliation: Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D064887:Observational Studies as Topic; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
references.citation: Breast Cancer. 2014 Nov;21(6):732-7
references.pmid: 23408123
references.citation: Tumour Biol. 2013 Apr;34(2):995-1004
references.pmid: 23296702
references.citation: Breast Cancer Res Treat. 2007 Nov;105(3):347-57
references.pmid: 17186359
references.citation: Cancer J. 2000 Jul-Aug;6(4):266-72
references.pmid: 11038147
references.citation: Breast J. 2010 Nov-Dec;16(6):625-32
references.pmid: 21070440
references.citation: Breast Cancer Res Treat. 2011 Feb;126(1):131-40
references.pmid: 20665107
references.citation: Breast. 2011 Apr;20(2):158-64
references.pmid: 21093260
references.citation: Br J Surg. 1984 Sep;71(9):711-4
references.pmid: 6478165
references.citation: Cancer. 2004 Sep 1;101(5):905-12
references.pmid: 15329896
references.citation: J Clin Oncol. 2011 Dec 20;29(36):4763-8
references.pmid: 22105824
references.citation: Med Oncol. 2012 Mar;29(1):16-24
references.pmid: 21193967
references.citation: Can Med Assoc J. 1984 Apr 1;130(7):881-6
references.pmid: 6322952
references.citation: Clin Breast Cancer. 2012 Apr;12(2):145-6
references.pmid: 22054710
references.citation: Gynecol Obstet Fertil. 2008 Jan;36(1):35-44
references.pmid: 18178120
references.citation: J Cancer Res Clin Oncol. 2012 Apr;138(4):705-14
references.pmid: 22237454
references.citation: Cancer. 2000 Jun 15;88(12):2739-50
references.pmid: 10870056
references.citation: Cir Esp. 2013 Mar;91(3):195-7
references.pmid: 23254145
references.citation: Cancer. 2011 Mar 1;117(5):907-15
references.pmid: 20945326
references.citation: Lancet Oncol. 2005 Jun;6(6):377-82
references.pmid: 15925815
references.citation: Eur J Surg Oncol. 2011 Jul;37(7):623-8
references.pmid: 21628090
references.citation: Cancer Genet Cytogenet. 2008 Jul;184(1):67-71
references.pmid: 18558293
references.citation: Clin Breast Cancer. 2012 Dec;12(6):398-403
references.pmid: 23083502
references.citation: N Y State J Med. 1980 May;80(6):908-10
references.pmid: 6250105
references.citation: Cancer. 2001 May 15;91(10):1845-53
references.pmid: 11346865
references.citation: Eur J Surg Oncol. 2002 Jun;28(4):388-91
references.pmid: 12099647
references.citation: Hum Mutat. 2010 Mar;31(3):E1200-40
references.pmid: 20104584
references.citation: BMC Cancer. 2012 Jun 06;12:217
references.pmid: 22672556
references.citation: World J Surg. 2001 Sep;25(9):1117-24
references.pmid: 11571945
references.citation: Asian Pac J Cancer Prev. 2012;13(9):4571-5
references.pmid: 23167382