title: The role of postmastectomy radiotherapy in clinically node-positive, stage II-III breast cancer patients with pathological negative nodes after neoadjuvant chemotherapy: an analysis from the NCDB.
abstract: OBJECTIVE
  The role of postmastectomy radiotherapy (PMRT) in clinically node-positive, stage II-III breast cancer patients with pathological negative nodes (ypN0) after neoadjuvant chemotherapy (NAC) remains controversial.
  
  
  METHODS
  A total of 1560 clinically node-positive, stage II-III breast cancer patients treated with NAC and mastectomy who achieved ypN0 between 1998 and 2009 in the National Cancer Database were analyzed. The effects of PMRT on overall survival (OS) for the entire cohort and multiple subgroups were evaluated. Imputation and propensity score matching were used as sensitivity analyses to minimize biases.
  
  
  RESULTS
  Of the entire 1560 eligible patients, 903 (57.9%) received PMRT and 657 (42.1%) didn't. At a median follow-up of 56.0 months, no statistical difference was observed for OS between two groups by univariate and multivariate analyses (P = 0.120; HR 1.571, 95% CI 0.839-2.943). On subgroup analyses, PMRT significantly improved OS in patients with clinical stage IIIB/IIIC disease, T3/T4 tumor, or residual invasive breast cancer after NAC (P < 0.05). This improvement in OS remained significant after sensitivity analyses for the propensity score-matched patients.
  
  
  CONCLUSIONS
  This study demonstrated that PMRT showed a heterogeneous effect in clinically node-positive, stage II-III breast cancer patients with ypN0 following NAC. PMRT improved OS for patients with clinical stage IIIB/IIIC disease, T3/T4 tumor, or residual invasive breast tumor after NAC. In the absence of definitive conclusions from prospective studies, including the ongoing NSABP B-51 trial, our findings may help identify specific groups of women with clinically node-positive, stage II-III breast cancers who could benefit from PMRT after NAC.
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Breast Tumor Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.|Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Jieqiong
authors.initials: J
authors.lastname: Liu
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Department of General Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.|Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Mao
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Shuai
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Department of Radiation Oncology, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Breast Tumor Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.|Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: Department of Neurological Surgery, Mayo Clinic Florida, Jacksonville, FL, USA.
authors.forename: Betty Y S
authors.initials: BY
authors.lastname: Kim
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Breast Tumor Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Jacobs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008408:Mastectomy / Q000379:methods*; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D009367:Neoplasm Staging; D011182:Postoperative Care / Q000379:methods*; D018714:Radiotherapy, Adjuvant / Q000379:methods*; D016019:Survival Analysis; D055815:Young Adult
keywords: breast cancer; complete pathological nodal response; neoadjuvant chemotherapy; postmastectomy radiotherapy; survival benefit