title: Role of postmastectomy radiation after neoadjuvant chemotherapy in stage II-III breast cancer.
abstract: OBJECTIVE
  To identify a cohort of women treated with neoadjuvant chemotherapy and mastectomy for whom postmastectomy radiation therapy (PMRT) may be omitted according to the projected risk of local-regional failure (LRF).
  
  
  METHODS
  Seven breast cancer physicians from the University of California cancer centers created 14 hypothetical clinical case scenarios, identified, reviewed, and abstracted the available literature (MEDLINE and Cochrane databases), and formulated evidence tables with endpoints of LRF, disease-free survival, and overall survival. Using the American College of Radiology appropriateness criteria methodology, appropriateness ratings for postmastectomy radiation were assigned for each scenario. Finally, an overall summary risk assessment table was developed.
  
  
  RESULTS
  Of 24 sources identified, 23 were retrospective studies from single institutions. Consensus on the appropriateness rating, defined as 80% agreement in a category, was achieved for 86% of the cases. Distinct LRF risk categories emerged. Clinical stage II (T1-2N0-1) patients, aged >40 years, estrogen receptor-positive subtype, with pathologic complete response or 0-3 positive nodes without lymphovascular invasion or extracapsular extension, were identified as having ≤ 10% risk of LRF without radiation. Limited data support stage IIIA patients with pathologic complete response as being low risk.
  
  
  CONCLUSIONS
  In the absence of randomized trial results, existing data can be used to guide the use of PMRT in the neoadjuvant chemotherapy setting. Using available studies to inform appropriateness ratings for clinical scenarios, we found a high concordance of treatment recommendations for PMRT and were able to identify a cohort of women with a low risk of LRF without radiation. These low-risk patients will form the basis for future planned studies within the University of California Athena Breast Health Network.
authors.affiliation: Department of Radiation Oncology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94143-1708, USA. bfowble@radonc.ucsf.edu
authors.forename: Barbara L
authors.initials: BL
authors.lastname: Fowble
authors.forename: John P
authors.initials: JP
authors.lastname: Einck
authors.forename: Danny N
authors.initials: DN
authors.lastname: Kim
authors.forename: Susan
authors.initials: S
authors.lastname: McCloskey
authors.forename: Jyoti
authors.initials: J
authors.lastname: Mayadev
authors.forename: Catheryn
authors.initials: C
authors.lastname: Yashar
authors.forename: Steven L
authors.initials: SL
authors.lastname: Chen
authors.forename: E Shelley
authors.initials: ES
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000367:Age Factors; D001943:Breast Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002140:California; D017024:Chemotherapy, Adjuvant / Q000379:methods; D015331:Cohort Studies; D003697:Delphi Technique; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008408:Mastectomy; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D018787:Radiation Oncology; D018570:Risk Assessment; D047368:Tumor Burden