TY - JOUR
T1 - Bone marrow mast cell burden and serum tryptase level as markers of response in patients with systemic mastocytosis
AU - Quintás-Cardama, Alfonso
AU - Sever, Matjaz
AU - Cortes, Jorge
AU - Kantarjian, Hagop
AU - Verstovsek, Srdan
PY - 2013/9
Y1 - 2013/9
N2 - Two important response criteria in systemic mastocytosis (SM) are the elimination or reduction in percentage of bone marrow mast cells (MCs) and the reduction of serum tryptase levels. We investigated the accuracy of a single time point reduction of bone marrow MCs and serum tryptase level as response criteria in 50 patients with SM with available serial assessments. Bone marrow MC percentage varied significantly, with an average coefficient of variation (CV) of 65% (range, 6-173%) and 44% of patients having a CV higher than the average. The average CV for serum tryptase level was 19% (range, 0-96%), with 36% of patients having a CV higher than average. These wide variations in bone marrow MC burden and serum tryptase level were independent of the administration of SM-directed therapy, type of therapy or disease subtype. Furthermore, the achievement of a single time point therapy-induced bone marrow complete response (no histological evidence of malignant bone marrow MCs) did not correlate with tryptase level or symptomatic improvement. In conclusion, the value of single measurements of bone marrow MC percentage and serum tryptase level as response criteria in SM is not supported by clinical data. Incorporation of an assessment of the degree in reduction of MCs and tryptase, and assessment of response durability, would make response criteria more clinically meaningful.
AB - Two important response criteria in systemic mastocytosis (SM) are the elimination or reduction in percentage of bone marrow mast cells (MCs) and the reduction of serum tryptase levels. We investigated the accuracy of a single time point reduction of bone marrow MCs and serum tryptase level as response criteria in 50 patients with SM with available serial assessments. Bone marrow MC percentage varied significantly, with an average coefficient of variation (CV) of 65% (range, 6-173%) and 44% of patients having a CV higher than the average. The average CV for serum tryptase level was 19% (range, 0-96%), with 36% of patients having a CV higher than average. These wide variations in bone marrow MC burden and serum tryptase level were independent of the administration of SM-directed therapy, type of therapy or disease subtype. Furthermore, the achievement of a single time point therapy-induced bone marrow complete response (no histological evidence of malignant bone marrow MCs) did not correlate with tryptase level or symptomatic improvement. In conclusion, the value of single measurements of bone marrow MC percentage and serum tryptase level as response criteria in SM is not supported by clinical data. Incorporation of an assessment of the degree in reduction of MCs and tryptase, and assessment of response durability, would make response criteria more clinically meaningful.
KW - Mast cell burden
KW - Response criteria
KW - Systemic mastocytosis
KW - Tryptase
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U2 - 10.3109/10428194.2012.763121
DO - 10.3109/10428194.2012.763121
M3 - Article
C2 - 23278641
AN - SCOPUS:84882995926
SN - 1042-8194
VL - 54
SP - 1959
EP - 1964
JO - Leukemia and Lymphoma
JF - Leukemia and Lymphoma
IS - 9
ER -