title: Persistence of myeloma protein for more than one year after radiotherapy is an adverse prognostic factor in solitary plasmacytoma of bone.
abstract: BACKGROUND
  Prognostic factors for solitary plasmacytoma of bone (SPB), whether measured before or after radiotherapy (RT), have not been established. The authors analyzed multiple factors for myeloma-free survival (MFS) and cause-specific survival (CSS) in SPB patients treated with RT alone.
  
  
  METHODS
  Between 1965 and 2000, 60 patients with carefully staged SPB were treated with RT alone at the M. D. Anderson Cancer Center. Patient ages ranged from 29-77 years (median, 54 years), and 75% of patients had a myeloma (M) protein in the blood and/or urine. No patients showed other lesions on skeletal survey or, in recent years, magnetic resonance imaging (MRI) of the spine; marrow aspirate was normal in all patients. Radiotherapy to the solitary lesion was given to a total dose of 30-70 Gy (median, 46 Gy). The authors analyzed the impact of multiple factors on MFS and CSS, including resolution v. persistence of M protein after RT, secretory v. nonsecretory disease at diagnosis, presence v. absence of an associated soft tissue mass on computed tomography or MRI scan, magnitude of serum M protein elevation at diagnosis, age, spinal v. nonspinal location, Karnofsky performance status, total RT dose, and tumor size.
  
  
  RESULTS
  Median follow-up was 7.8 years (range, 1.0-25.5 years). On multivariate analysis, persistence of M protein more than one year after RT was the only independent adverse prognostic factor for MFS (P = 0.005) and CSS (P = 0.04). Most patients with M protein that persisted for more than one year after RT were diagnosed with multiple myeloma within 2.2 years of treatment.
  
  
  CONCLUSIONS
  Patients with M protein that persists for more than one year after RT should be monitored frequently and considered for standard chemotherapy followed by intensive consolidation therapy when they either develop symptoms or show an increasing M protein level.
authors.affiliation: Department of Radiation Oncology, M.D. Anderson Cancer Center, Houston, Texas, USA. rwilder@mdanderson.org
authors.forename: Richard B
authors.initials: RB
authors.lastname: Wilder
authors.forename: Chul S
authors.initials: CS
authors.lastname: Ha
authors.forename: James D
authors.initials: JD
authors.lastname: Cox
authors.forename: Donna
authors.initials: D
authors.lastname: Weber
authors.forename: Kay
authors.initials: K
authors.lastname: Delasalle
authors.forename: Raymond
authors.initials: R
authors.lastname: Alexanian
mesh_terms: D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000473:pathology*; D009194:Myeloma Proteins / Q000032:analysis*; D010954:Plasmacytoma / Q000473:pathology* / Q000532:radiotherapy*; D011379:Prognosis; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D009194:Myeloma Proteins; C085016:multiple myeloma M-proteins