title: Validation of a novel staging system for disease-specific survival in patients with breast cancer treated with neoadjuvant chemotherapy.
abstract: OBJECTIVE
  We previously described a novel breast cancer staging system for assessing prognosis after neoadjuvant chemotherapy on the basis of pretreatment clinical stage (CS), estrogen receptor status (E), grade (G), and post-treatment pathologic stage (PS). This clinical-pathologic stage (CPS) + EG staging system assigned and summed points for each factor, allowing for better determination of breast cancer-specific survival than CS or PS alone. The current study was undertaken to validate this staging system using internal and external cohorts.
  
  
  METHODS
  We identified an internal cohort of 804 patients treated with neoadjuvant chemotherapy at our institution from 2003 to 2005 and an external cohort of 165 patients treated at another institution. Clinicopathologic characteristics, treatment regimens, and patient outcomes were assessed. Outcomes were stratified by CPS + EG score.
  
  
  RESULTS
  Five-year disease-specific survival (DSS) for the internal cohort was 77% (95% CI, 72 to 82) at a median follow-up of 3.4 years (range, 0.3 to 5.9 years). Five-year DSS for the external cohort was 86% (95% CI, 79 to 91) at a median follow-up of 4.7 years (range, 0.5 to 10.5 years). The ability of the CPS + EG score to stratify outcomes was confirmed in both the internal and external cohorts. Application of the CPS + EG staging system facilitated more refined categorization of patients into prognostic subgroups by outcome than presenting CS or final PS as defined by the American Joint Committee on Cancer (AJCC) staging system.
  
  
  CONCLUSIONS
  The current study validates the CPS + EG staging system in two independent cohorts. We recommend that biologic markers and response to treatment be incorporated into revised versions of the AJCC staging system for patients receiving neoadjuvant chemotherapy.
authors.affiliation: University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Mittendorf
authors.forename: Jacqueline S
authors.initials: JS
authors.lastname: Jeruss
authors.forename: Susan L
authors.initials: SL
authors.lastname: Tucker
authors.forename: Aparna
authors.initials: A
authors.lastname: Kolli
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Newman
authors.forename: Ana M
authors.initials: AM
authors.lastname: Gonzalez-Angulo
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Buchholz
authors.forename: Aysegul A
authors.initials: AA
authors.lastname: Sahin
authors.forename: Janice N
authors.initials: JN
authors.lastname: Cormier
authors.forename: Aman U
authors.initials: AU
authors.lastname: Buzdar
authors.forename: Gabriel N
authors.initials: GN
authors.lastname: Hortobagyi
authors.forename: Kelly K
authors.initials: KK
authors.lastname: Hunt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D011960:Receptors, Estrogen