A high bone marrow plasma cell labeling index in stable plateau-phase multiple myeloma is a marker for early disease progression and death

The plasma cell labeling index (PCLI) is a measure of plasma cell prolifera tive activity and is an important prognostic factor in newly diagnosed mult iple myeloma (MM). Occasionally patients have been observed with stable, pl ateau phase MM with minimal numbers of residual light-chain-restricted mono clonal plasma cells, but a high PCLI. No data are available on the outcomes for such patients. Data from 57 patients with plateau phase MM and a marro w PCLI of more than 1.0% were compared with 105 matched control patients wi th MM with a marrow PCLI of less than 1.0%. All patients had less than 10% total plasma cells on marrow aspirate and biopsy. The median time to progre ssion and overall survival were 8 months and 20 months, respectively, in th e high PCLI group versus 39 months and 56 months, respectively, in the low PCLI group (P < .0001). These findings suggest that a high PCLI in patients with apparently stable, plateau phase MM is an adverse parameter that may predict a short time to disease progression and death. (Blood, 2001;97:2522 -2523) (C) 2001 by The American Society of Hematology.