title: Long-term survival outcomes following internal mammary node irradiation in stage II-III breast cancer: results of a large retrospective study with 12-year follow-up.
abstract: OBJECTIVE
  To examine the effect of internal mammary node irradiation (IMNI) on disease-free survival (DFS) and overall survival (OS) in breast cancer patients treated with modified radical mastectomy and postoperative radiation therapy.
  
  
  METHODS
  Between 1994 and 2002, 396 patients with stage II-III breast cancer were treated with postmastectomy radiation therapy with (n=197) or without (n=199) IMNI. Patients who received neoadjuvant chemotherapy were excluded. IMNI was administered at the clinical discretion of the treating physician. Median RT dose was 50.4 Gy (range, 45.0-59.4 Gy) in 28 fractions, with inclusion of the supraclavicular fossa in 96% of patients. Adjuvant chemotherapy was administered to 99.7% of the patients and endocrine therapy to 53%.
  
  
  RESULTS
  The median follow-up was 149 months (range, 124-202). IMNI patients had more advanced nodal stage and non-high grade tumors than those without IMNI (P<.001). Otherwise, disease and treatment characteristics were well balanced. The 10-year DFS with and without IMNI was 65% and 57%, respectively (P=.05). Multivariate analysis demonstrated that IMNI was an independent, positive predictor of DFS (hazard ratio [HR], 0.70; P=.02). Benefits of IMNI in DFS were seen most apparently in N2 patients (HR, 0.44; 95% confidence interval [CI], 0.26-0.74) and inner/central tumors (HR, 0.55; 95% CI, 0.34-0.90). The 10-year OS with and without IMNI was 72% and 66%, respectively (P=.62). The 10-year DFS and OS were 61%, and 69%, respectively.
  
  
  CONCLUSIONS
  Internal mammary node irradiation significantly improved DFS in postmastectomy breast cancer patients. Pending long-term results from randomized trials, treatment of internal mammary nodes should be considered in postmastectomy radiation therapy.
authors.affiliation: Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jee Suk
authors.initials: JS
authors.lastname: Chang
authors.forename: Won
authors.initials: W
authors.lastname: Park
authors.forename: Yong Bae
authors.initials: YB
authors.lastname: Kim
authors.forename: Ik Jae
authors.initials: IJ
authors.lastname: Lee
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Keum
authors.forename: Chang Geol
authors.initials: CG
authors.lastname: Lee
authors.forename: Doo Ho
authors.initials: DH
authors.lastname: Choi
authors.forename: Chang-Ok
authors.initials: CO
authors.lastname: Suh
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Huh
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001365:Axilla; D001943:Breast Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D018275:Carcinoma, Lobular / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D017024:Chemotherapy, Adjuvant / Q000379:methods; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods; D015182:Lymphatic Irradiation / Q000401:mortality*; D015411:Mastectomy, Modified Radical / Q000379:methods / Q000401:mortality; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology; D012189:Retrospective Studies; D055815:Young Adult