title: Tumor response ratio predicts overall survival in breast cancer patients treated with neoadjuvant chemotherapy.
abstract: BACKGROUND
  Neoadjuvant chemotherapy (NAC) is commonly used to treat locally advanced breast cancer. Pathologic complete response (pCR) predicts improved overall survival (OS); however, prognosis of patients with partial response remains unclear. We evaluated whether tumor response ratio (TRR) is a better predictor of OS than current staging methods.
  
  
  METHODS
  Using the National Comprehensive Cancer Network Breast Cancer Outcomes Database, we identified patients with stage I-III breast cancer who had NAC and pretreatment imaging at City of Hope (1997-2010). Patient demographics, tumor characteristics, and OS were analyzed. TRR was calculated as residual in-breast disease divided by size on pre-NAC imaging. Four TRR groups were stratified; TRR 0 (pCR), TRR > 0-0.4 (strong partial response, SPR), TRR > 0.4-1.0 (weak partial response, WPR), or TRR > 1.0 (tumor growth, TG). OS was estimated by the Kaplan-Meier method and tested by the log-rank test. Cox regression was performed to evaluate associations between OS and TRR in a multivariable analysis while controlling for potential confounders.
  
  
  RESULTS
  There were 218 eligible patients identified; 59 (27 %) had pCR, 61 (28 %) SPR, 72 (33 %) WPR, and 26 (12 %) TG. Five-year OS decreased continuously with increasing TRR:pCR (90 %), SPR (79 %), WPR (66 %), and TG (60 %). TRR was the only measure that significantly predicted OS (p = 0.0035); pathologic stage (p = 0.23) and pre-NAC clinical tumor stage (cT) (p = 0.87) were not significant. TRR continued to be statistically significant by multivariable analysis (p = 0.016).
  
  
  CONCLUSIONS
  TRR takes into account both pretreatment and residual disease and more accurately predicts OS than pathologic stage and pre-NAC cT. TRR may be useful to more accurately assess prognosis and OS in breast cancer patients undergoing NAC.
authors: Department of Surgical Oncology, City of Hope, Duarte, CA, USA.
authors: Marian
authors: M
authors: Miller
authors: Rebecca A
authors: RA
authors: Ottesen
authors: Joyce C
authors: JC
authors: Niland
authors: Laura
authors: L
authors: Kruper
authors: Steven L
authors: SL
authors: Chen
authors: Courtney
authors: C
authors: Vito
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D018275:Carcinoma, Lobular / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate