title: A Prognostic Model for Patients with Triple-Negative Breast Cancer: Importance of the Modified Nottingham Prognostic Index and Age.
abstract: OBJECTIVE
  Considering the distinctive biology of triple-negative breast cancer (TNBC), this study aimed to identify TNBC-specific prognostic factors and determine the prognostic value of the Nottingham Prognostic Index (NPI) and its variant indices.
  
  
  METHODS
  A total of 233 patients with newly diagnosed stage I to III TNBC from 2003 to 2012 were reviewed. We retrospectively analyzed the patients' demographics, clinicopathologic parameters, treatment, and survival outcomes. The NPI was calculated as follows: tumor size (cm)×0.2+node status+Scarff-Bloom-Richardson (SBR) grade. The modified NPI (MNPI) was obtained by adding the modified SBR grade rather than the SBR grade.
  
  
  RESULTS
  The median follow-up was 67.8 months. Five-year disease-free survival (DFS) and overall survival (OS) were 81.4% and 89.9%, respectively. Multivariate analyses showed that the MNPI was the most significant and common prognostic factor of DFS (p=0.001) and OS (p=0.019). Young age (≤35 years) was also correlated with poor DFS (p=0.006). A recursive partitioning for establishing the prognostic model for DFS was performed based on the results of multivariate analysis. Patients with a low MNPI (≤6.5) were stratified into the low-risk group (p<0.001), and patients with a high MNPI (>6.5) were subdivided into the intermediate (>35 years) and high-risk (≤35 years) groups. Age was not a prognostic factor in patients with a low MNPI, whereas in patients with a high MNPI, it was the second key factor in subdividing patients according to prognosis (p=0.023).
  
  
  CONCLUSIONS
  The MNPI could be used to stratify patients with stage I to III TNBC according to prognosis. It was the most important prognosticator for both DFS and OS. The prognostic significance of young age for DFS differed by MNPI.
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jeanny
authors.initials: J
authors.lastname: Kwon
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.; Breast Care Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Keun-Yong
authors.initials: KY
authors.lastname: Eom
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Tae Ryool
authors.initials: TR
authors.lastname: Koo
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Byoung Hyuck
authors.initials: BH
authors.lastname: Kim
authors.affiliation: Breast Care Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Eunyoung
authors.initials: E
authors.lastname: Kang
authors.affiliation: Breast Care Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Sung-Won
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Breast Care Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Yu Jung
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Breast Care Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea.; Breast Care Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: In Ah
authors.initials: IA
authors.lastname: Kim
keywords: Age factors; Prognosis; Triple negative breast neoplasms