title: Incidence and prognostic factors of Japanese breast cancer patients with bone metastasis.
abstract: BACKGROUND
  Few previous studies have analyzed the incidence of bone metastases in a defined population of Japanese breast cancer patients and their prognosis after chemotherapy.
  
  
  METHODS
  This is a retrospective cohort study. We investigated 695 patients who underwent surgery for breast cancer. The strategy of adjuvant therapy was as follows. Patients with both estrogen receptors (ERs) and progesterone receptors (PgRs) had endocrine therapy as initial adjuvant therapy (n = 239). Patients with neither ERs nor PgRs had chemotherapy. When metastasis to other organs, including bone, was identified, patients received chemotherapy. The survival rates after surgery and after the onset of bone metastasis, as well as the incidence of bone metastasis, were calculated. We also evaluated the prognostic and predictive factors.
  
  
  RESULTS
  Bone metastases developed in 148 of 695 patients. All 148 received chemotherapy, and 121 of them developed spinal metastases. The 5-year survival rate after bone metastases was 26.1%. Prognostic factors for bone metastases were visceral metastases and PgR status. Cord compression was observed in 17 of the 148 patients, with the thoracic spine being the most common. The 1-year survival rate for patients with bone metastases who received chemotherapy was 66.3%, whereas that of patients with paralysis after spinal metastases was 17.6%. Within 6 months of the development of spinal cord compression, 70.6% of the patients died.
  
  
  CONCLUSIONS
  We reported the incidence and prognostic factors for a defined population of Japanese breast cancer patients with bone and spinal metastases. Our results suggest that the expected survival time for patients with paralysis who received adequate endocrine therapy or chemotherapy is generally poor. However, to detect a predictive factor of long survival after paralysis and establish the indications for surgery, a comparative study among large groups of patients with paralysis and with different backgrounds is necessary.
authors.affiliation: Department of Orthopaedic Surgery, Tokyo Metropolitan Komagome Hospital, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Oka
authors.forename: Taiji
authors.initials: T
authors.lastname: Kondoh
authors.forename: Atsushi
authors.initials: A
authors.lastname: Seichi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hozumi
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000453:epidemiology* / Q000556:secondary* / Q000628:therapy; D001943:Breast Neoplasms / Q000473:pathology*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013125:Spinal Neoplasms / Q000453:epidemiology* / Q000556:secondary*; D015996:Survival Rate