title: Clinical significance following breast conservation therapy with or without irradiation in breast cancer patients.
abstract: BACKGROUND
  We retrospectively examined the clinical outcome of irradiated versus non-irradiated groups of Japanese breast cancer patients according to their clinical and histopathological characteristics following breast-conserving therapy.
  
  
  METHODS
  We retrospectively evaluated a total of 1197 Japanese female breast cancer patients (598 irradiated and 599 non-irradiated) who received breast-conserving therapy. The median age of the patients was 54 years (range: 24-99 years). We retrospectively examined the local recurrence-free survival rates in those with or without post-operative irradiation according to age, surgical margin status and histopathological characteristics including histological grade, estrogen receptor expression and HER2 status.
  
  
  RESULTS
  Local recurrence-free survival rates in the irradiated group were significantly higher than those in the non-irradiated group, especially in surgical margin-positive [hazard ratio (HR): 0.334, 95% confidence interval: 0.14-0.79, P = 0.001], estrogen receptor-positive (HR: 0.249, 95% confidence interval: 0.11-0.54, P < 0.001), HER2-negative (HR: 0.382, 95% confidence interval: 0.21-0.69, P = 0.001) and non-triple-negative (HR: 0.382, 95% confidence interval: 0.21-0.69, P = 0.001) breast cancer patients.
  
  
  CONCLUSIONS
  The results indicated that irradiation after breast-conserving therapy is strongly recommended in Japanese breast cancer patients, especially those with surgically positive margins, estrogen receptor-positive tumors and HER2-negative invasive breast cancers.
authors.affiliation: Department of Breast Surgery, Nahanishi Clinic, 2-1-9 Akamine, Naha, Okinawa, Japan. k-tamaki@naha-nishi-clinic.or.jp
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tamaki
authors.forename: Nobumitsu
authors.initials: N
authors.lastname: Tamaki
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kamada
authors.forename: Kanou
authors.initials: K
authors.lastname: Uehara
authors.forename: Noriaki
authors.initials: N
authors.lastname: Ohuchi
authors.forename: Minoru
authors.initials: M
authors.lastname: Miyashita
authors.forename: Takanori
authors.initials: T
authors.lastname: Ishida
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sasano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018714:Radiotherapy, Adjuvant; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone