title: Twenty-year incidence and patterns of contralateral breast cancer after breast conservation treatment with radiation.
abstract: OBJECTIVE
  This study was undertaken to determine the incidence of contralateral breast cancer (CLB) after treatment for early-stage breast cancer with breast-conserving treatment (BCT), and to observe patterns of CLB presentation.
  
  
  METHODS
  Medical records of 1,801 women treated for unilateral AJCC Stage 0-II breast cancer with BCT between 1977 and 2000 were analyzed as a retrospective cohort.
  
  
  RESULTS
  The incidence of any CLB at 20 years was 15.4%. The annual risk of developing any CLB remained constant at approximately 0.75% per year after treatment. The median time to any CLB was 8.2 years (range, 0.5-26.5 years). No difference in incidence of CLB was demonstrated in patients with primary invasive carcinoma vs. DCIS (p = 0.84). The majority of patients (83%) developing CLB tumors developed invasive disease. The risk of developing an invasive CLB did not differ significantly for patients with DCIS vs. those with primary invasive carcinoma (p = 0.20). The method of detection of the primary tumor (mammography vs. physical examination) was not predictive of detection of the CLB (p = 0.20). Finally, the location of CLB tumors was not affected by that of prior tumors (p = 0.82).
  
  
  CONCLUSIONS
  The risk of development of CLB persists for at least 20 years after treatment for early-stage breast cancer. CLB tumors are frequently invasive, and their location is not influenced by location of prior tumors. Mammography and physical examination remain essential after BCT for detection of a contralateral breast cancer, regardless of the method of detection of the primary tumor.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. hill@xrt.upenn.edu
authors.forename: Christine E
authors.initials: CE
authors.lastname: Hill-Kayser
authors.forename: Eleanor E R
authors.initials: EE
authors.lastname: Harris
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Hwang
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Solin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000532:radiotherapy*; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy; D018275:Carcinoma, Lobular / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology* / Q000473:pathology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D013997:Time Factors