title: Reduction in plasma cell proliferation after initial therapy in newly diagnosed multiple myeloma measures treatment response and predicts improved survival.
abstract: Standard myeloma treatment response criteria are determined principally by changes in the monoclonal protein. Reduction in the size of the proliferative component of malignant plasma cells may be an additional metric of assessing response to therapy. We retrospectively analyzed 176 patients with newly diagnosed myeloma with a measurable plasma cell labeling index (PCLI) at diagnosis and repeat measurement 4 months after initiation of therapy. PCLI response was defined as a ≥ 60% reduction. Baseline PCLI is an independent prognostic factor; therefore, we categorized patients into 3 groups: PCLI ≥ 3% (high), ≥ 1% (intermediate), and < 1% (low). Patients achieving a greater PCLI response had improved median overall survival of 54 months compared with 29 months in nonresponders (P = .02). Improved median overall survival with PCLI response occurred in the high initial PCLI group (28 vs 7 months; P = .003) and intermediate group (64 vs 24 months; P = .002). The application of PCLI response and serum M-spike response together provided further prognostic information. On multivariate analysis, the prognostic value of PCLI response was independent of β(2)-microglobulin, elevated creatinine, serum M-spike response, and baseline PCLI. We conclude that a significant reduction in plasma cell proliferation in patients with newly diagnosed myeloma is an important predictor of survival.
authors.affiliation: Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Jeremy T
authors.initials: JT
authors.lastname: Larsen
authors.forename: Cheng E
authors.initials: CE
authors.lastname: Chee
authors.forename: John A
authors.initials: JA
authors.lastname: Lust
authors.forename: Philip R
authors.initials: PR
authors.lastname: Greipp
authors.forename: S Vincent
authors.initials: SV
authors.lastname: Rajkumar
mesh_terms: D000328:Adult; D000368:Aged; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D002097:C-Reactive Protein / Q000378:metabolism; D049109:Cell Proliferation; D005260:Female; D005455:Fluorescent Antibody Technique; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009101:Multiple Myeloma / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D010950:Plasma Cells / Q000166:cytology*; D011379:Prognosis; D015996:Survival Rate; D001613:beta 2-Microglobulin / Q000378:metabolism
chemical_list: D001613:beta 2-Microglobulin; D002097:C-Reactive Protein