title: Outcomes of positron emission tomography-staged clinical N3 breast cancer treated with neoadjuvant chemotherapy, surgery, and radiotherapy.
abstract: OBJECTIVE
  To evaluate the treatment outcome and efficacy of regional lymph node irradiation after neoadjuvant chemotherapy (NCT) and surgery in positron emission tomography (PET)-positive clinical N3 (cN3) breast cancer patients.
  
  
  METHODS
  A total of 55 patients with ipsilateral infraclavicular (ICL), internal mammary (IMN), or supraclavicular (SCL) lymph node involvement in the absence of distant metastases, as revealed by an initial PET scan, were retrospectively analyzed. The clinical nodal stage at diagnosis (2002 AJCC) was cN3a in 14 patients (26%), cN3b in 12 patients (22%), and cN3c in 29 patients (53%). All patients were treated with NCT, followed by mastectomy or breast-conserving surgery and subsequent radiotherapy (RT) with curative intent.
  
  
  RESULTS
  At the median follow-up of 38 months (range, 9-80 months), 20 patients (36%) had developed treatment failures, including distant metastases either alone or combined with locoregional recurrences that included one ipsilateral breast recurrence (IBR), six regional failures (RF), and one case of combined IBR and RF. Only 3 patients (5.5%) exhibited treatment failure at the initial PET-positive clinical N3 lymph node. The 5-year locoregional relapse-free survival, disease-free survival (DFS), and overall survival rates were 80%, 60%, and 79%, respectively. RT delivered to PET-positive IMN regions in cN3b patients and at higher doses (≥55 Gy) to SCL regions in cN3c patients was not associated with improved 5-year IMN/SCL relapse-free survival or DFS.
  
  
  CONCLUSIONS
  NCT followed by surgery and RT, including the regional lymph nodes, resulted in excellent locoregional control for patients with PET-positive cN3 breast cancer. The primary treatment failure in this group was due to distant metastasis rather than RF. Neither higher-dose RT directed at PET-positive SCL nodes nor coverage of PET-positive IMN nodes was associated with additional gains in locoregional control or DFS.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Hae Jin
authors.initials: HJ
authors.lastname: Park
authors.forename: Kyung Hwan
authors.initials: KH
authors.lastname: Shin
authors.forename: Kwan Ho
authors.initials: KH
authors.lastname: Cho
authors.forename: In Hae
authors.initials: IH
authors.lastname: Park
authors.forename: Keun Seok
authors.initials: KS
authors.lastname: Lee
authors.forename: Jungsil
authors.initials: J
authors.lastname: Ro
authors.forename: So-Youn
authors.initials: SY
authors.lastname: Jung
authors.forename: Seeyoun
authors.initials: S
authors.lastname: Lee
authors.forename: Seok Won
authors.initials: SW
authors.lastname: Kim
authors.forename: Han-Sung
authors.initials: HS
authors.lastname: Kang
authors.forename: Eui Kyu
authors.initials: EK
authors.lastname: Chie
authors.forename: Sung Whan
authors.initials: SW
authors.lastname: Ha
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D017024:Chemotherapy, Adjuvant / Q000379:methods; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015182:Lymphatic Irradiation; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging / Q000379:methods; D049268:Positron-Emission Tomography; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D015996:Survival Rate; D017211:Treatment Failure
chemical_list: D000970:Antineoplastic Agents