title: Hazard of recurrence among women after primary breast cancer treatment--a 10-year follow-up using data from SEER-Medicare.
abstract: BACKGROUND
  Few studies have used SEER-Medicare data to describe recurrence of breast cancer after primary treatment for U.S. women.
  
  
  METHODS
  We used SEER-Medicare data to estimate the annual hazard rate (HR) of recurrence for women with breast cancer between 1991 and 1997 with 10 years of follow-up. The Kaplan-Meier method was used to derive the HR. Multivariate Cox proportional hazards model was used to estimate the relative hazard of the recurrence-associated prognostic factors.
  
  
  RESULTS
  Of 20,027 women, 36.8% had recurrence within 10 years, with most of these recurrences (81.9%) occurring within 5 years after diagnosis. Women with stage III cancer showed the highest HR peak and largest magnitude than women with stage I or II disease (both P < 0.01) within the first 5 years. Women with negative tumor hormone receptor status had a higher peak hazard of developing recurrence within the first 5 years (P < 0.01), but the hazards were remarkably lower beyond 5 years of follow-up than in women with positive or unknown hormone receptor status (P > 0.05). Women with poorly differentiated histologic grade tumors showed higher HR in the first 5 years than women with other grades after primary treatment (both P < 0.01). The increased risk of recurrence of breast cancer was associated with advanced stage, moderate and poorly differently grades, and negative hormone receptor status (all P < 0.01).
  
  
  CONCLUSIONS
  The HRs of the recurrence are dynamic over 10 years and are markedly determined by prognostic factors at diagnosis.
  
  
  CONCLUSIONS
  Our study suggests that the optimal follow-up may differ among women.
authors.affiliation: Department of Clinical Effectiveness, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. lcheng@mdanderson.org
authors.forename: Lee
authors.initials: L
authors.lastname: Cheng
authors.forename: Michael D
authors.initials: MD
authors.lastname: Swartz
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao
authors.forename: Asha S
authors.initials: AS
authors.lastname: Kapadia
authors.forename: Dejian
authors.initials: D
authors.lastname: Lai
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Rowan
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Buchholz
authors.forename: Sharon H
authors.initials: SH
authors.lastname: Giordano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology* / Q000473:pathology; D011379:Prognosis; D016016:Proportional Hazards Models; D018426:SEER Program; D014481:United States / Q000453:epidemiology