Chromosome 13 abnormalities identified by FISH analysis and serum β2-microglobulin produce a powerful myeloma staging system for patients receiving high-dose therapy

Abstract

A careful prognostic evaluation of patients referred for high-dose therapy (HDT) is warranted to identify those who maximally benefit from HDT as well as those who clearly fail current HDT and are candidates for more innovative treatments. In a series of 110 patients with myeloma who received HDT as first-line therapy, times to event (disease progression and death) were studied through proportional hazard models, in relation to different prognostic factors, including a chromosome 13 fluorescence in situ hybridization (FISH) analysis using a D13S319 probe. Δ13 was detected in 42 patients (38%). Follow-up time among surviving patients and survival time were 48 ± 3 and 51 ± 7 months, respectively (median ± SE). In the univariate analysis, Δ13 was the most powerful adverse prognostic factor for all times to event, especially for the survival time (P < .0001) and was followed by β2-microglobulin (β2m) levels 2.5 mg/L or higher (P = .0001). The comparison of survival prognostic models including β2m 2.5 mg/L or greater and another factor favored the Δ13/β2m combination. In 22 patients (20%) with no unfavorable factor, the median survival time was not reached at 111 months. In contrast, among 55 patients (50%) with one unfavorable factor and 33 patients (30%) with 2 unfavorable factors, median survival times were 47.3 ± 4.6 months and 25.3 ± 3.2 months, respectively (P < .0001). We conclude that Δ13, adequately detected by FISH analysis, is a very strong factor related to poor survival, especially when associated with a β2m level of 2.5 mg/L or higher. Routine FISH Δ13 assessment is strongly recommended for patients considered for HDT.