title: Methods for estimation of bone marrow plasma cell involvement in myeloma: predictive value for response and survival in patients undergoing autologous stem cell transplantation.
abstract: In myeloma, the bone marrow plasma cell percentage (BMPC%) is usually estimated independently on the aspirate, core biopsy, and plasma cell labeling index (PCLI) samples. This study was done to determine which of the 3 individual estimates correlates best with complete response (CR) and survival. Seventy-five consecutive patients who underwent SCT for relapsed myeloma were studied. The median BMPC% on the marrow aspirate, core biopsy, and PCLI studies were 20, 25, and 20, respectively. There was a significant correlation between the three methods, rho > 0.65, P < 0.001. However, in 8% of patients the BMPC% was different by an absolute value of 50% between methods. No individual method was predictive for CR. However, the highest estimate of the BMPC% among the three methods was a significant predictor of CR (P = 0.02). Survival following SCT was longer among patients with a low BMPC% (< or =60) by the PCLI method compared to those with higher values, median survival 23 versus 7 months, respectively, P = 0.02. PFS was also different, with survival times of 11 and 5 months, respectively, P = 0.003. Similar results were obtained when the highest estimate of the BMPC% was used in survival analysis (P = 0.02 and 0.004, respectively). Statistical significance was lower when the BMPC% on the aspirate or biopsy used in survival analysis. Compared to any individual method of estimating BMPC%, the highest estimate of the BMPC% is the best predictor of CR in myeloma. It is also prognostic for poor survival and PFS following SCT for myeloma. We recommend that all three methods of estimating BMPC% be routinely performed and that the highest value be used for prognostic purposes.
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, Minnesota 55905, USA. rajkumar.vincent@mayo.edu
authors.forename: S V
authors.initials: SV
authors.lastname: Rajkumar
authors.forename: R
authors.initials: R
authors.lastname: Fonseca
authors.forename: A
authors.initials: A
authors.lastname: Dispenzieri
authors.forename: M Q
authors.initials: MQ
authors.lastname: Lacy
authors.forename: J A
authors.initials: JA
authors.lastname: Lust
authors.forename: T E
authors.initials: TE
authors.lastname: Witzig
authors.forename: T M
authors.initials: TM
authors.lastname: Therneau
authors.forename: R A
authors.initials: RA
authors.lastname: Kyle
authors.forename: P R
authors.initials: PR
authors.lastname: Greipp
authors.forename: M A
authors.initials: MA
authors.lastname: Gertz
mesh_terms: D000328:Adult; D000368:Aged; D001854:Bone Marrow Cells / Q000473:pathology*; D002452:Cell Count; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008297:Male; D008722:Methods; D008875:Middle Aged; D009101:Multiple Myeloma / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D010950:Plasma Cells / Q000473:pathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D016019:Survival Analysis; D014182:Transplantation, Autologous; D016896:Treatment Outcome