Kumar, Shaji

SummaryDespite the absence of high‐risk cytogenetics and lower International Staging System (ISS) stages, a subset of patients with multiple myeloma (MM) experience poor overall survival (OS). We studied 1461 patients with newly diagnosed MM to identify patient and disease characteristics that predict a high‐risk phenotype among standard‐risk patients. Fifty‐six percent of all patients presented with standard‐risk disease. Among them, advanced age, extremes of body mass index, non‐hyperdiploid karyotype and abnormal lymphocyte counts were associated with worse OS. Standard‐risk patients with 0–1 of these adverse factors (hazard ratio [HR] 0·32, 95% confidence interval [CI] 0·24–0·43, P < 0·001) and 2 adverse factors (HR 0·54, 95% CI 0·41–0·72, P < 0·001) experienced better OS than high‐risk patients. Two or more adverse factors were present in 17% of standard‐risk patients and were associated with OS comparable to high‐risk patients (HR 0·91, 95% CI 0·67–1·24, P = 0·548). Predictive power among standard‐risk patients was improved using score groups compared to ISS stages. Patients with standard‐risk MM are a heterogeneous group with one in six patients experiencing OS comparable to high‐risk disease. Patients at risk can be identified using readily available patient and disease characteristics. These findings emphasize the importance of accurate risk stratification and help explain part of the heterogeneity observed in clinical practice.

AbstractTrisomies of odd numbered chromosomes are seen in nearly half of patients with multiple myeloma (MM) and typically correlate with a hyperdiploid state and better overall survival (OS). We compared DNA ploidy of monoclonal plasma cells (as a surrogate for the presence of trisomies) assessed simultaneously by PCPRO (plasma cell proliferative index), a novel method that estimates DNA index by multi‐parametric flow cytometry to fluorescence in situ hybridization (FISH) in 1703 patients with plasma cell disorders. The distribution of ploidy was hyperdiploid: 759 (45%), diploid 765 (45%), hypodiploid: 71 (4%), tetraploid/near‐tetraploid: 108 (6%). FISH identified trisomies in 82% (621/756) of patients with hyperdiploidy by PCPRO and no trisomy by FISH was observed in 88% (730/834) of patients without hyperdiploidy. 95% (795/834) of patients without hyperdiploidy on PCPRO had one or less trisomy by FISH. Sensitivity and specificity of PCPRO for detecting hyperdiploidy was 86% (621/725) and 84% (730/865), respectively. Sensitivity increased to 94% (579/618) for patients with more than one trisomy. Newly diagnosed MM patients with hyperdiploidy on PCPRO (147/275) had better OS compared to nonhyperdiploid patients (median not reached vs 59 months, P = 0.008) and better progression free survival (median: 33 vs 23 months, P = 0.03). Within the hyperdiploidy group, patients with high‐hyperdiploidy (DNA index: 1.19‐1.50) versus those with low‐hyperdiploidy (DNA index: 1.05‐1.18) had superior OS (3 year OS of 88% vs 68% P = 0.03). Ploidy assessment by flow cytometry can provide rapid, valuable prognostic information and also reduces the number of copy number FISH probes required and hence the cost of FISH.