title: Progesterone receptor loss identifies hormone receptor-positive and HER2-negative breast cancer subgroups at higher risk of relapse: a retrospective cohort study.
abstract: BACKGROUND
  To assess the prognostic value of progesterone receptor (PR) expression in patients with hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer subgroups.
  
  
  METHODS
  A retrospective review of breast cancer patients who underwent mastectomy or breast-conserving surgery between January 1998 and December 2007 was performed. The prognostic impact of PR status on disease-free survival (DFS) was analyzed.
  
  
  RESULTS
  Of the 1,301 patients included in this study, the median follow-up time was 64 months, and the median age was 46 years. There were 18.4% of patients (n=219) with PR negative (PR-) cancer. Women with PR-breast cancer were more likely to be postmenopausal (P<0.001) and have pN3 stage (P=0.031) and Stage III (P=0.049) cancer. Cox regression univariate and multivariate analysis showed that PR status was a significant prognostic factor for DFS. Patients with PR- status had poorer DFS (hazard ratio =1.626, 95% confidence interval =1.060-2.497, P=0.026). The 5-year DFS for patients with PR- and PR+ breast cancer was 79.4% and 86.2%, respectively, and the 8-year DFS for patients with PR- and PR+ breast cancer was 69.6% and 78.1%, respectively (P=0.012). A significant difference in DFS was observed between PR- and PR+ disease in patients with node-negative cancer, but was not for patients with lymph node metastasis (P=0.242). In premenopausal patients, DFS varied significantly by PR status (P=0.049). A marginally significant difference in DFS between the PR- and PR+ disease was seen in postmenopausal patients (log rank P=0.065).
  
  
  CONCLUSIONS
  Lack of PR expression is associated with worse survival in patients with hormone receptor-positive and HER2-negative breast cancer subgroups.
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China.
authors.forename: Jia-Yuan
authors.initials: JY
authors.lastname: Sun
authors.affiliation: Department of Radiation Oncology, Xiamen Cancer Center, The First Affiliated Hospital of Xiamen University, Xiamen, People's Republic of China.
authors.forename: San-Gang
authors.initials: SG
authors.lastname: Wu
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China.
authors.forename: Feng-Yan
authors.initials: FY
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China.
authors.forename: Huan-Xin
authors.initials: HX
authors.lastname: Lin
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China.
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: He
keywords: breast cancer; breast cancer subtype; progesterone receptor; prognosis; recurrence