title: Validating a prognostic scoring system for postmastectomy locoregional recurrence in breast cancer.
abstract: OBJECTIVE
  This study is designed to validate a previously developed locoregional recurrence risk (LRR) scoring system and further define which groups of patients with breast cancer would benefit from postmastectomy radiation therapy (PMRT).
  
  
  METHODS
  An LRR risk scoring system was developed previously at our institution using breast cancer patients initially treated with modified radical mastectomy between 1990 and 2001. The LRR score comprised 4 factors: patient age, lymphovascular invasion, estrogen receptor negativity, and number of involved lymph nodes. We sought to validate the original study by examining a new dataset of 1545 patients treated between 2002 and 2007.
  
  
  RESULTS
  The 1545 patients were scored according to the previously developed criteria: 920 (59.6%) were low risk (score 0-1), 493 (31.9%) intermediate risk (score 2-3), and 132 (8.5%) were high risk (score ≥4). The 5-year locoregional control rates with and without PMRT in low-risk, intermediate-risk, and high-risk groups were 98% versus 97% (P=.41), 97% versus 91% (P=.0005), and 89% versus 50% (P=.0002) respectively.
  
  
  CONCLUSIONS
  This analysis of an additional 1545 patients treated between 2002 and 2007 validates our previously reported LRR scoring system and suggests appropriate patients for whom PMRT will be beneficial. Independent validation of this scoring system by other institutions is recommended.
authors.affiliation: Department of Radiation Oncology, Koo Foundation Sun Yat-Sen Cancer Center, Taipei, Taiwan. skye@kfsyscc.org
authors.forename: Skye Hung-Chun
authors.initials: SH
authors.lastname: Cheng
authors.forename: Stella Y
authors.initials: SY
authors.lastname: Tsai
authors.forename: Ben-Long
authors.initials: BL
authors.lastname: Yu
authors.forename: Cheng-Fang
authors.initials: CF
authors.lastname: Horng
authors.forename: Chii-Ming
authors.initials: CM
authors.lastname: Chen
authors.forename: James J
authors.initials: JJ
authors.lastname: Jian
authors.forename: Nan-Min
authors.initials: NM
authors.lastname: Chu
authors.forename: Mei-Hua
authors.initials: MH
authors.lastname: Tsou
authors.forename: Mei-Ching
authors.initials: MC
authors.lastname: Liu
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Huang
authors.forename: Leonard R
authors.initials: LR
authors.lastname: Prosnitz
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000737:chemistry / Q000145:classification / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D015411:Mastectomy, Modified Radical / Q000145:classification; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D016016:Proportional Hazards Models; D011960:Receptors, Estrogen / Q000032:analysis; D018570:Risk Assessment / Q000379:methods*; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D011960:Receptors, Estrogen