Contributions
Abstract: PB1528
Type: Publication Only
Session title: Chronic myeloid leukemia - Clinical
Background
Chronic myeloid leukemia (CML) is a clonal disorder of myeloid origin. Paraproteinemias are a group of disorders arising from the clonal proliferation of a lymphoid origin leading to the production of a monoclonal (M-) protein. Though originating from different cell origins, there have been several reports describing patients with coexistence of CML and multiple myeloma (MM) or other paraproteinemias, mostly in patients treated with tyrosine kinase inhibitors (TKIs).
Aims
To determine whether the prevalence of paraproteinemia in a large cohort of CML patients is higher than in the general population in a tertiary medical center.
Methods
This is a cross sectional study among chronic phase CML patients treated in the Institute of Hematology at the Rabin Medical Center, a university affiliated tertiary medical center in Israel. Between February 2019 and Februray 2021 consecutive patients with a diagnosis of chronic phase CML, who gave their consent to the study, performed the following serum samples: protein electrophoresis & immunofixation (SPEP, IFIX), serum free light chains (FLC) and quantitative immunoglobulin (Ig) levels. The study’s primary outcome was the prevalence of paraproteinemia among this cohort of CML patients. Secondary outcomes evaluated the correlations between paraproteinemia and various patient, disease and treatment-related variables. The study was approved by the Institutional Review Board.
Results
A total of 96 patients were recruited. Data for the analysis were available for 90 of them. Patients’ characteristics are presented in Table 1.
On SPEP - 18 patients (20%) had hypergammaglobulinemia, 14 patients (15.5%) had hypogammaglobulinemia and 58 patients (64.5%) had normal gammaglobulin fraction.
M-protein was detected on SPEP and IFIX in 6 patients (6.6%) with a median age of 71.5 years (range 46-74). Among them, two patients had also an abnormal FLC and elevated IgG or IgA levels with corresponding immunoparesis of the uninvolved Ig heavy chain. These patients underwent a bone marrow biopsy and skeletal imaging and were diagnosed with IgG-kappa and IgA-kappa smoldering multiple myeloma (SMM). The other four patients had normal FLCs and their characteristics were compatible with the diagnosis of low risk monoclonal gammopathy of undetermined significance (MGUS). None of the patients in our cohort was diagnosed with active MM.
All six patients with an M-protein are currently under observation for their newly-diagnosed paraproteinemia.
At enrollment, five of the six patients with a detectable M-protein were treated with a TKI [imatinib (n=2), dasatinib (n=2), bosutinib (n=1)] and one had been in TFR for two months, after 6 years of imatinib therapy.
Conclusion
To the best of our knowledge this is the largest study to describe the prevalence of paraproteinemia among CML patients. We found the prevalence of MGUS in chronic phase CML patients (4.4%) to be similar to that of the general population above the age of 50 years. Nonetheless, we found a non-negligible prevalence of SMM (2.2%), a relatively uncommon clinical entity. Based on these data, we recommend to consider screening for paraproteinemia coexistence in patients with CML, since this might have a clinical impact. Further studies, including extended follow up of the present cohort should elucidate the true clinical significance of our findings.
Keyword(s): Chronic myeloid leukemia, Monoclonal gammopathy, Myeloma, Smoldering
Abstract: PB1528
Type: Publication Only
Session title: Chronic myeloid leukemia - Clinical
Background
Chronic myeloid leukemia (CML) is a clonal disorder of myeloid origin. Paraproteinemias are a group of disorders arising from the clonal proliferation of a lymphoid origin leading to the production of a monoclonal (M-) protein. Though originating from different cell origins, there have been several reports describing patients with coexistence of CML and multiple myeloma (MM) or other paraproteinemias, mostly in patients treated with tyrosine kinase inhibitors (TKIs).
Aims
To determine whether the prevalence of paraproteinemia in a large cohort of CML patients is higher than in the general population in a tertiary medical center.
Methods
This is a cross sectional study among chronic phase CML patients treated in the Institute of Hematology at the Rabin Medical Center, a university affiliated tertiary medical center in Israel. Between February 2019 and Februray 2021 consecutive patients with a diagnosis of chronic phase CML, who gave their consent to the study, performed the following serum samples: protein electrophoresis & immunofixation (SPEP, IFIX), serum free light chains (FLC) and quantitative immunoglobulin (Ig) levels. The study’s primary outcome was the prevalence of paraproteinemia among this cohort of CML patients. Secondary outcomes evaluated the correlations between paraproteinemia and various patient, disease and treatment-related variables. The study was approved by the Institutional Review Board.
Results
A total of 96 patients were recruited. Data for the analysis were available for 90 of them. Patients’ characteristics are presented in Table 1.
On SPEP - 18 patients (20%) had hypergammaglobulinemia, 14 patients (15.5%) had hypogammaglobulinemia and 58 patients (64.5%) had normal gammaglobulin fraction.
M-protein was detected on SPEP and IFIX in 6 patients (6.6%) with a median age of 71.5 years (range 46-74). Among them, two patients had also an abnormal FLC and elevated IgG or IgA levels with corresponding immunoparesis of the uninvolved Ig heavy chain. These patients underwent a bone marrow biopsy and skeletal imaging and were diagnosed with IgG-kappa and IgA-kappa smoldering multiple myeloma (SMM). The other four patients had normal FLCs and their characteristics were compatible with the diagnosis of low risk monoclonal gammopathy of undetermined significance (MGUS). None of the patients in our cohort was diagnosed with active MM.
All six patients with an M-protein are currently under observation for their newly-diagnosed paraproteinemia.
At enrollment, five of the six patients with a detectable M-protein were treated with a TKI [imatinib (n=2), dasatinib (n=2), bosutinib (n=1)] and one had been in TFR for two months, after 6 years of imatinib therapy.
Conclusion
To the best of our knowledge this is the largest study to describe the prevalence of paraproteinemia among CML patients. We found the prevalence of MGUS in chronic phase CML patients (4.4%) to be similar to that of the general population above the age of 50 years. Nonetheless, we found a non-negligible prevalence of SMM (2.2%), a relatively uncommon clinical entity. Based on these data, we recommend to consider screening for paraproteinemia coexistence in patients with CML, since this might have a clinical impact. Further studies, including extended follow up of the present cohort should elucidate the true clinical significance of our findings.
Keyword(s): Chronic myeloid leukemia, Monoclonal gammopathy, Myeloma, Smoldering