Contributions
Abstract: PB1828
Type: Publication Only
Background
Generally, chronic myeloid leukemia (CML) and essential thrombocythemia (ET) are characterized by distinctive clinical and laboratory characteristics, including the spectrum of genetic abnormalities - Philadelphia chromosome (Ph) and BCR-ABL1 fusion transcripts in CML and JAK2, CALR or MPL gene mutations in ET. Therefore, even in the presence of overlapping features in some cases, the correct diagnosis can be assigned. However, in rare cases Ph chromosome and BCR-ABL1 fusion transcripts can be found in otherwise typical ET. Due to the low number of reported cases the subsequent course of the disease and the response to tyrosine kinase inhibitors (TKI) in such patients with BCR-ABL1-positive thrombocytosis is largely unknown.
Aims
Methods
In total, 31 pts with Ph(+) and/or BCR-ABL1(+) isolated thrombocytosis and a moderate or absent leukocytosis were retrieved from the hospital database. The cohort comprised 17 females and 14 males, at a median age of 47 years (range 23-86). Diagnosis was based on blood and bone marrow morphology and differential, cytogenetics and/or molecular testing according to the WHO criteria (2008). Molecular monitoring was carried out using Xpert BCR-ABL Monitor or Xpert BCR-ABL Ultra tests (Cepheid). In total, follow up data for at least 6 months (mean 65 months) are available for 25 patients treated with TKI as a first-line therapy.
Results
At diagnosis the median leukocyte count was 22 x109/l (range 6-36) and platelet count – 1316x109/l (range 770-2815). Splenomegaly was found in 5 pts (16.1%). Only one patient was diagnosed in accelerated phase as the remaining presented in chronic phase at diagnosis. Interestingly, 4 pts (12.9%) had a history of an antecedent solid tumor. All patients enrolled in the study were BCR-ABL1(+): b3a2 (n=16) or b2a2 (n=15). Karyotypes were available in 23 pts and classical Ph was found in 16 of them (69.6%), while in 5 pts (21.7%) a cryptic translocation was detected as well as a variant Ph in the remaining 2 pts (8.7%). Imatinib was used as a first line therapy in 15 pts and optimal response was achieved in 53.3% (n=8), while 5 were switched to a second line, and 2 - to a third line therapy. First-line treatment with Nilotinib in 10 patients resulted in optimal response in 80% (n=8). In total, major molecular response (MR) was achieved in 80% (n=20), including deep MR in 56% (n=14). One pt was lost of follow up after optimal response was registered. No response was documented in 4 pts (16%) and progression to blast crisis developed in 2 of them. The mean OS was estimated 143 months and the cumulative proportion surviving at 5 years was 91%.
Conclusion
Interestingly, CML presenting with isolated thrombocytosis at diagnosis in our cohort had high proportion of antecedent malignancies and high incidence of cryptic Ph translocation without any specific correlation with the transcript types. However, the clinical course and molecular response to TKI therapy was similar to the reported in CML in general. Ackowledgements: Partial support by the National Science Fund.
Session topic: 8. Chronic myeloid leukemia - Clinical
Keyword(s): Thrombocytosis, Molecular response, Chronic myeloid leukemia
Abstract: PB1828
Type: Publication Only
Background
Generally, chronic myeloid leukemia (CML) and essential thrombocythemia (ET) are characterized by distinctive clinical and laboratory characteristics, including the spectrum of genetic abnormalities - Philadelphia chromosome (Ph) and BCR-ABL1 fusion transcripts in CML and JAK2, CALR or MPL gene mutations in ET. Therefore, even in the presence of overlapping features in some cases, the correct diagnosis can be assigned. However, in rare cases Ph chromosome and BCR-ABL1 fusion transcripts can be found in otherwise typical ET. Due to the low number of reported cases the subsequent course of the disease and the response to tyrosine kinase inhibitors (TKI) in such patients with BCR-ABL1-positive thrombocytosis is largely unknown.
Aims
Methods
In total, 31 pts with Ph(+) and/or BCR-ABL1(+) isolated thrombocytosis and a moderate or absent leukocytosis were retrieved from the hospital database. The cohort comprised 17 females and 14 males, at a median age of 47 years (range 23-86). Diagnosis was based on blood and bone marrow morphology and differential, cytogenetics and/or molecular testing according to the WHO criteria (2008). Molecular monitoring was carried out using Xpert BCR-ABL Monitor or Xpert BCR-ABL Ultra tests (Cepheid). In total, follow up data for at least 6 months (mean 65 months) are available for 25 patients treated with TKI as a first-line therapy.
Results
At diagnosis the median leukocyte count was 22 x109/l (range 6-36) and platelet count – 1316x109/l (range 770-2815). Splenomegaly was found in 5 pts (16.1%). Only one patient was diagnosed in accelerated phase as the remaining presented in chronic phase at diagnosis. Interestingly, 4 pts (12.9%) had a history of an antecedent solid tumor. All patients enrolled in the study were BCR-ABL1(+): b3a2 (n=16) or b2a2 (n=15). Karyotypes were available in 23 pts and classical Ph was found in 16 of them (69.6%), while in 5 pts (21.7%) a cryptic translocation was detected as well as a variant Ph in the remaining 2 pts (8.7%). Imatinib was used as a first line therapy in 15 pts and optimal response was achieved in 53.3% (n=8), while 5 were switched to a second line, and 2 - to a third line therapy. First-line treatment with Nilotinib in 10 patients resulted in optimal response in 80% (n=8). In total, major molecular response (MR) was achieved in 80% (n=20), including deep MR in 56% (n=14). One pt was lost of follow up after optimal response was registered. No response was documented in 4 pts (16%) and progression to blast crisis developed in 2 of them. The mean OS was estimated 143 months and the cumulative proportion surviving at 5 years was 91%.
Conclusion
Interestingly, CML presenting with isolated thrombocytosis at diagnosis in our cohort had high proportion of antecedent malignancies and high incidence of cryptic Ph translocation without any specific correlation with the transcript types. However, the clinical course and molecular response to TKI therapy was similar to the reported in CML in general. Ackowledgements: Partial support by the National Science Fund.
Session topic: 8. Chronic myeloid leukemia - Clinical
Keyword(s): Thrombocytosis, Molecular response, Chronic myeloid leukemia