# IMWG consensus definition of primary plasma cell leukaemia at 5 percent circulating plasma cells

Source: https://onco.cc/key-papers/paper-imwg-plasma-cell-leukaemia-definition-bcj-2021/  
OnCo record `paper-imwg-plasma-cell-leukaemia-definition-bcj-2021` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The International Myeloma Working Group lowered the threshold for diagnosing plasma cell leukaemia from 20 percent to 5 percent circulating plasma cells, because patients at 5 percent already have the same dismal outlook.

## Summary

Consensus statement from the International Myeloma Working Group reviewing evidence that 5 percent or more circulating plasma cells on a blood film carries the same poor survival as the historical 20 percent threshold, and redefining primary plasma cell leukaemia accordingly, with recommendations for work-up.

## Fields

- Kind: Key paper
- Last checked: 2026-09-17
- Journal: Blood cancer journal
- Year: 2021
- DOI: 10.1038/s41408-021-00587-0
- Authors: Fernández de Larrea C, Kyle R, Rosiñol L, et al.
- What it means: More patients now receive the diagnosis and the intensive, transplant-based approach that goes with it; trial eligibility uses the new definition.
- Caveats: Based on retrospective series; treatment recommendations remain largely extrapolated from myeloma.

## Sources

- Blood Cancer J 2021: https://doi.org/10.1038/s41408-021-00587-0
- PubMed: https://pubmed.ncbi.nlm.nih.gov/34857730/

## Connected records

- cancers: [Plasma cell leukaemia](https://onco.cc/cancers/plasma-cell-leukaemia/)
- journals: [Blood cancer journal](https://onco.cc/journals/blood-cancer-journal/)

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