title: Outcomes and patterns of failure in solitary plasmacytoma: a multicenter Rare Cancer Network study of 258 patients.
abstract: OBJECTIVE
  To assess the outcomes and patterns of failure in solitary plasmacytoma (SP).
  
  
  METHODS
  The data from 258 patients with bone (n = 206) or extramedullary (n = 52) SP without evidence of multiple myeloma (MM) were collected. A histopathologic diagnosis was obtained for all patients. Most (n = 214) of the patients received radiotherapy (RT) alone; 34 received chemotherapy and RT, and 8 surgery alone. The median radiation dose was 40 Gy. The median follow-up was 56 months (range 7-245).
  
  
  RESULTS
  The median time to MM development was 21 months (range 2-135), with a 5-year probability of 45%. The 5-year overall survival, disease-free survival, and local control rate was 74%, 50%, and 86%, respectively. On multivariate analyses, the favorable factors were younger age and tumor size <4 cm for survival; younger age, extramedullary localization, and RT for disease-free survival; and small tumor and RT for local control. Bone localization was the only predictor of MM development. No dose-response relationship was found for doses >30 Gy, even for larger tumors.
  
  
  CONCLUSIONS
  Progression to MM remains the main problem. Patients with extramedullary SP had the best outcomes, especially when treated with moderate-dose RT. Chemotherapy and/or novel therapies should be investigated for bone or bulky extramedullary SP.
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. mahmut.ozsahin@chuv.ch
authors.forename: Mahmut
authors.initials: M
authors.lastname: Ozsahin
authors.forename: Richard W
authors.initials: RW
authors.lastname: Tsang
authors.forename: Philip
authors.initials: P
authors.lastname: Poortmans
authors.forename: Yazid
authors.initials: Y
authors.lastname: Belkacémi
authors.forename: Michel
authors.initials: M
authors.lastname: Bolla
authors.forename: Fazilet Oner
authors.initials: FO
authors.lastname: Dinçbas
authors.forename: Christine
authors.initials: C
authors.lastname: Landmann
authors.forename: Bernard
authors.initials: B
authors.lastname: Castelain
authors.forename: Jeroen
authors.initials: J
authors.lastname: Buijsen
authors.forename: Jürgen
authors.initials: J
authors.lastname: Curschmann
authors.forename: Sidney P
authors.initials: SP
authors.lastname: Kadish
authors.forename: Anna
authors.initials: A
authors.lastname: Kowalczyk
authors.forename: Yavuz
authors.initials: Y
authors.lastname: Anacak
authors.forename: Josef
authors.initials: J
authors.lastname: Hammer
authors.forename: Tan D
authors.initials: TD
authors.lastname: Nguyen
authors.forename: Gabriela
authors.initials: G
authors.lastname: Studer
authors.forename: Rachel
authors.initials: R
authors.lastname: Cooper
authors.forename: Meriç
authors.initials: M
authors.lastname: Sengöz
authors.forename: Luciano
authors.initials: L
authors.lastname: Scandolaro
authors.forename: Abderrahim
authors.initials: A
authors.lastname: Zouhair
mesh_terms: D000704:Analysis of Variance; D001859:Bone Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000473:pathology; D010954:Plasmacytoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016896:Treatment Outcome