FEATURE
New IMWG Diagnostic Criteria
Allow for Earlier Diagnosis
Updates Represent a “Paradigm Shift” for Multiple Myeloma Treatment
U
nlike most other malignancies,
the disease definition of multiple
myeloma is clinicopathologic:
Myeloma must be confirmed on biopsy
by a pathologist, and a patient must have
clinical manifestations of disease. This
creates a “hurry-up-and-wait” conundrum, though – particularly for patients
with smoldering multiple myeloma, who
have an ultra-high risk of progression to
full-blown disease. They have pathologic
evidence without clinical sequelae, with a
consequent,
and appropriate, delay
in therapy
initiation.
In late
October
2014, the International
Myeloma
Working Group
S. Vincent Rajkumar, MD
(IMWG;
the research division of the International
Myeloma Foundation) released updated
diagnostic criteria for multiple myeloma.
The guidelines, published in The Lancet
Oncology, represent a paradigm shift for
multiple myeloma treatment – and, since
MD, lead author of the Lancet Oncology
manuscript. Dr. Rajkumar is also a professor of medicine and chair of the Myeloma
Amyloidosis Dysproteinemia Group at
the Mayo Clinic in Rochester, Minnesota.
“Early therapy is critical if we are ever going to cure this disease.”
New Definitions Incorporate
Technical Advances
Multiple myeloma is a blood cancer affecting the plasma cells and is frequently
preceded by two asymptomatic premalignant conditions: monoclonal gammopathy of undetermined significance
(MGUS) or smoldering multiple myeloma. Previously, diagnosis of multiple
myeloma has relied on the presence of
one or more “CRAB” features: increased
calcium level, renal failure, anemia, and
destructive bone lesions.
The new diagnostic criteria – an overview of which is provided in the SIDEBAR
– allows physicians to identify “pre-CRAB” patients using validated biomarkers
before end-organ damage has occurred.
The three markers, called “myelomadefining events” include:
• Sixty percent or greater clonal plasma
cells on bone marrow examination
“ e are now willing to treat
W
multiple myeloma before
symptoms happen.”
—S. VINCENT RAJKUMAR, MD
earlier treatment could lead to better outcomes, new hope for improved survival in
patients diagnosed with this disease.
It has been 11 years since the IMWG
issued its last diagnostic criteria. However, the authors of the recent manuscript
wrote, “This definition can no longer be
justified.”
“[The previous definition] was fine
when we had very limited options for
therapy, but it’s not fine when we have
such great treatments that have more than
doubled the survival of multiple myeloma
patients,” said S. Vincent Rajkumar,
76
ASH Clinical News
• An involved/uninvolved free light
chain ratio of ≥100 or greater,
provided the absolute level of the
involved free light chain is ≥100 mg/L
(a patient’s “involved” free light chain
– either kappa or lambda – is the one
that is above the normal reference
range; the “uninvolved” light chain is
the one that typically is in, or below,
the normal range)
• More than one focal lesion on magnetic resonance imaging (MRI) that is
≥5 mm in size
The presence of at least one of these three
markers will be considered sufficient for
a diagnosis of multiple myeloma, regardless of the presence or absence of CRAB
feature 2