title: [Clinical analysis of multiple myeloma patients with bone-related extramedullary disease: a longitudinal study on 834 consecutive patients in a single center of China].
abstract: OBJECTIVE
  To analyse the incidence, clinical features, prognosis of bone-related extramedullary disease （bEMD） and its relationship with strict EMD (sEMD) in MM patients.
  
  
  METHODS
  The records of 834 consecutive newly diagnosed patients with MM in our hospital between 1993 and 2013 were retrospectively reviewed.
  
  
  RESULTS
  ①Among 834 patients at diagnosis, 32 cases (3.8%) showed bEMD, and 40 cases (4.8%) showed sEMD. Patients with bEMD at presentation showed significant lower level of lactate dehydrogenase (180.9 U/L vs 299.2 U/L, P=0.034) and higher overall response rate (ORR) (95.7% vs 66.7%, P=0.009) compared with sEMD patients. While the above two parameters were comparable between patients with bEMD and without EMD. ②As to the prognosis of patients without autologous hematopoietic stem cell transplantation (auto-HSCT), the overall survival (OS) of patients with sEMD, bEMD and without EMD was 14.0, 37.5, and 38.0 months, respectively. The time to progression (TTP) of the three groups was 11.5, 27.0, and 22.0 months, respectively. Compared to the patients with sEMD, the outcomes (both OS and TTP) of the other two groups was significantly better (P<0.05). Patients with bEMD at presentation was comparable to the patients without EMD, but the two groups were better than the patients with sEMD. ③The incidence of bEMD during follow-up was 0.5%. The OS of patients with sEMD, bEMD and without EMD during follow-up was 26.0, 17.0, and 40.0 months, respectively. The TTP of the three groups was 13.0, 11.0, and 25.0 months, respectively. The outcomes (both OS and TTP) of patients with bEMD at relapse/progression showed no significant difference as compared with the other two groups (P>0.05).
  
  
  CONCLUSIONS
  The clinical features of MM patients with bEMD are different from the patients with sEMD. Outcomes of this population is significantly better than the latter, and is comparable to the patients without EMD. It suggests that bEMD alone has no negative prognostic significance in MM patients.
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Shuhui
authors.initials: S
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Gang
authors.initials: G
authors.lastname: An
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Sui
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Zengjun
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Dehui
authors.initials: D
authors.lastname: Zou
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Yaozhong
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Junyuan
authors.initials: J
authors.lastname: Qi
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin　300020, China.
authors.forename: Lugui
authors.initials: L
authors.lastname: Qiu
mesh_terms: D001847:Bone Diseases; D002681:China; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D009101:Multiple Myeloma; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012189:Retrospective Studies