title: Impact of lymph node status on clinical outcomes after accelerated partial breast irradiation.
abstract: OBJECTIVE
  To compare outcomes after accelerated partial breast irradiation (APBI) between node-negative and node-positive patients.
  
  
  METHODS
  A total of 534 patients with early-stage breast cancer received APBI including 39 node-positive (N+) cases. Clinical, pathologic, and treatment-related factors were compared between node-negative (N-) and N+ cohorts. Local recurrence (LR), regional recurrence (RR), axillary failure (AF), distant metastases (DM), disease-free survival (DFS), cause-specific survival (CSS), and overall survival (OS) were analyzed.
  
  
  RESULTS
  N+ patients were younger (p = 0.04), had larger tumors (p < 0.001), and were more likely to receive chemotherapy (p < 0.001). Mean follow-up was 7.8 years for N+ patients and 6.3 years for N- patients (p = 0.06). No differences were seen in 5-year actuarial rates of LR (2.2% vs. 2.6%, p = 0.86), AF (0% vs. 0%, p = 0.69), DFS (90.0% vs. 88.0%, p = 0.79), or OS (91.0 vs. 84.0%, p = 0.65) between the two groups, whereas higher rates of RR (0% vs. 6.1%, p < 0.001) and DM (2.2% vs. 8.9%, p = 0.005) were noted in N+ patients. A trend for improved CSS (p = 0.06), was seen in N- patients. Age, tumor size, receptor status, T-stage, chemotherapy, APBI technique, and nodal status (p = 0.86) were not associated with LR, while a trend for an association with LR was noted with close/positive margins, (p = 0.07), and failure to receive adjuvant hormonal therapy (p = 0.06).
  
  
  CONCLUSIONS
  No differences were seen in the rates of LR or AF between N- and N+ patients after APBI. These results support the continued enrollment of node-positive patients in Phase III trials evaluating the efficacy of APBI including the National Surgical Adjuvant Breast and Bowel Project-B39/Radiation Therapy Oncology Group 0413.
authors.affiliation: Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI, USA.
authors.forename: Chirag
authors.initials: C
authors.lastname: Shah
authors.forename: J Ben
authors.initials: JB
authors.lastname: Wilkinson
authors.forename: Simona
authors.initials: S
authors.lastname: Shaitelman
authors.forename: Inga S
authors.initials: IS
authors.lastname: Grills
authors.forename: Peter Y
authors.initials: PY
authors.lastname: Chen
authors.forename: Nayana
authors.initials: N
authors.lastname: Dekhne
authors.forename: Ishmael
authors.initials: I
authors.lastname: Jaiyesimi
authors.forename: Michelle
authors.initials: M
authors.lastname: Wallace
authors.forename: Christina K
authors.initials: CK
authors.lastname: Mitchell
authors.forename: Frank A
authors.initials: FA
authors.lastname: Vicini
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy; D001943:Breast Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D020266:Radiotherapy, Conformal; D016896:Treatment Outcome; D047368:Tumor Burden