|Year : 2021 | Volume
| Issue : 4 | Page : 208-213
A retrospective analysis of clinicopathological features and treatment outcomes of patients with chronic myeloid leukemia at a tertiary hospital
Sohaila Fatima MBBS, MD 1, Abdulrahman Alshehri2, Wajih A Siddiqui2, Shahid Aziz3
1 Department of Pathology, Aseer Central Hospital, Abha, KSA
2 Department of Hematology and Oncology, Aseer Central Hospital, Abha, KSA
3 Internal Medicine, King Khalid University Abha, KSA
|Date of Submission||28-Oct-2021|
|Date of Acceptance||07-Dec-2021|
|Date of Web Publication||18-May-2022|
Department of Pathology, King Khalid University, PO Box 641, Postal Code 61421, Abha
Source of Support: None, Conflict of Interest: None
Introduction Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that shows the characteristic formation of the Philadelphia chromosome, containing the BCR-ABL1 fusion gene.
Objective The experience with patients with CML regarding clinical features, as well as efficacy and safety of tyrosine kinase inhibitors (TKIs) as a treatment for CML was analyzed in this study.
Materials and methods A retrospective study was conducted in patients diagnosed with CML regarding clinicomorphological features and treatment outcome in a tertiary hospital located in southwest Saudi Arabia from July 2004 to June 2020. The study population included patients diagnosed with CML who were older than 12 years. Patients younger than 12 years, BCR-ABL-negative CML, and other myeloproliferative neoplasm were not included in the study. Medical records of patients were reviewed, and data were collected.
Results During this period, 80 patients with CML were treated. The mean age was 41.6 years, with a slight male predominance. Overall, 90% of patients presented with abdominal discomfort and fatigue. Chronic phase represented 90% of all cases, with 55.5% showing intermediate-risk category of the Sokal score. Patients receiving a first-line treatment with first-generation TKI represented 42.5% and second-generation TKIs represented 52.5%. Complete hematological response was noted in 96.2% of patients after 3 months of treatment, and a major molecular response was seen in 77.2% of patients after 12 months of treatment. Adverse events (AEs) of TKI noted were 16 (20%), of which 81.2% were grade 1. They were as follows: pleural effusion in four (5%), neutropenia in two (2.5%), bone marrow suppression in four (5%), and skin itching in six (7.5%) in patients with dasatinib, contributing to 56.2% of all AEs. Overall, four (5%) patients were in treatment-free remission. Mean survival period in chronic phase CML was found to be 15.4 years, whereas in advanced phase CML was 4.7 years.
Conclusion Our study revealed that patients with CML were predominantly middle aged with a slight male preponderance. Most patients presented in the chronic phase, with the Sokal score in the intermediate-risk category. Patients were treated upfront with TKIs with a significant number receiving second-generation TKIs. First-generation TKIs had lesser AEs as compared with second-generation TKIs, but these toxicities were mild.
Keywords: clinicopathological features, CML, outcome, TKI, treatment
|How to cite this article:|
Fatima S, Alshehri A, Siddiqui WA, Aziz S. A retrospective analysis of clinicopathological features and treatment outcomes of patients with chronic myeloid leukemia at a tertiary hospital. Egypt J Haematol 2021;46:208-13
|How to cite this URL:|
Fatima S, Alshehri A, Siddiqui WA, Aziz S. A retrospective analysis of clinicopathological features and treatment outcomes of patients with chronic myeloid leukemia at a tertiary hospital. Egypt J Haematol [serial online] 2021 [cited 2022 Aug 13];46:208-13. Available from: http://www.ehj.eg.net/text.asp?2021/46/4/208/345389
| Introduction|| |
Myeloproliferative neoplasms (MPN) are clonal disorders. Chronic myeloid leukemia (CML) is an MPN which results due to t (9;22) (q34.1; q11 .2), leading to the formation of Philadelphia (Ph) chromosome, in which granulocytes are the major proliferative component. The translocation affects hematopoietic stem cell, resulting in BCR-ABL1 fusion gene . BCR-ABL1 is a hybrid gene that codes for a 210-KDa leukemogenic tyrosine kinase (TK) protein . The BCR-ABL protein formed as a result is an inherently active TK that can phosphorylate a variety of substrates, resulting in the activation of various signaling pathways that regulate cell growth and differentiation. These clonal cells are able to overcome normal growth limits and become leukemic . CML progresses between a chronic phase (CP) and an advanced phase (AP) that may contain an accelerated phase (AP), a blast crisis phase (BP), or both. The global yearly incidence of CML is 1–2 per 100 000 people and accounts for approximately 15% of newly diagnosed leukemia cases in adults with a slight male predominance . According to the Saudi Cancer Registry 2017 report, CML accounts for 0.62% of all newly diagnosed cancer cases in adults . Several prognostic indices are used to stratify patients with CML, the most common of which are Sokal , Hasford , and the European Treatment and Outcome Study (EUTOS) . Sokal studied individuals with chronic CML and developed a technique for calculating a score based on multivariate analysis. The Sokal score is calculated using the patient’s age, spleen size, platelet count, and blast percentage in the blood  and is classified into low risk (0.8), intermediate risk (0.8–1.2), and high risk (>1.2). Our experience with patients with CML regarding clinicopathological features and the efficacy and safety of tyrosine kinase inhibitors (TKIs) as a treatment for CML was expressed in this study.
| Materials and methods|| |
This was a retrospective study conducted in a tertiary hospital located in southwest Saudi Arabia in patients diagnosed with CML who were treated from July 2004 to June 2020 regarding clinicomorphological features, risk stratification by the Sokal score, and treatment outcome.
The study population included patients diagnosed with CML who were older than 12 years. Patients younger than 12 years, BCR-ABL-negative CML, and other MPN were not included in the study. The sample size was 80 patients.
Study tools and data collection
Medical records of patients were reviewed and age, sex, risk stratification by Sokal score, treatment, adverse effects of TKIs, and hematological and molecular remission were noted.
Sokal score=exp ([0.0116×(age in years–43.4)]+[0.0345×(spleen size in cm–7.51)]+[0.188×((platelets in 109/L/700)2–0.563)]+[0.0887×(blasts in %–2.10)]).
The primary outcome was hematological remission and secondary outcome was molecular remission.
Hematological remission was determined by complete blood count and peripheral blood smears, and molecular analysis was done by RQ-PCR on peripheral blood.
Complete hematologic response (CHR) includes white blood cell count less than or equal to 11.0×103/μl; platelets less than 450×103/μl; absence of blasts and promyelocytes; myelocytes plus metamyelocytes less than 5%; basophils less than 20%; and no extramedullary involvement. CHR that has been confirmed for at least four weeks after it was initially documented on Day 14 is referred to be confirmed CHR. Cytogenetic response categories included complete cytogenetic response (CCyR) (0% Ph-positive metaphases), partial cytogenetic response (PCyR) (1–35% Ph-positive metaphases), major cytogenetic response (MCyR) (≤35% Ph-positive metaphases), and minor cytogenetic response (>35% to 95% Ph-positive metaphases).
Molecular response was assessed according to the International Scale (IS) as the ratio of BCR-ABL1 transcripts to ABL1 transcripts, reported as BCR-ABL1% on a log scale. BCR-ABL1 transcript level less than or equal to 0.1% corresponding to a decrease of 3 logs below the standardized baseline was defined as a major molecular response (MMR) or MR3 .
Hydroxyurea (HU) was used for cytoreduction, at a dose of 1–4 g/day, depending on the white blood cell count, presence of symptoms, and urgency to lower the white blood count. It was overlapped with TKIs, and once white blood cells count reached less than 100×103/μl HU, it was stopped and patient was continued on TKI.
In females, once pregnancy was confirmed, the patient was shifted to pegylated interferon (PEG-IFN) alfa-2a therapy at a dose of 90–180 μg/week subcutaneously followed by TKIs after delivery.
TKIs were given orally in conventional doses: imatinib 400 mg every 24 h, nilotinib 300 mg every 12 h, and dasatinib 100 mg every 24 h.
The choice of TKIs was according to the Sokal score, patient’s age, the existence of comorbid conditions, and anticipated complications of these drugs. Imatinib was given to any patient unless resistance or complication developed. Dasatinib was avoided in patients with congestive heart failure, pleural disease, or bleeding diathesis. Nilotinib was avoided in patients with cardiac disease with prolonged QT interval, uncontrolled diabetes mellitus, and pancreatitis.
In case of toxicity owing to any TKIs, medication was withheld for 1–2 weeks till symptoms resolved and then rechallenged with adjusted dosage with close observation and monitoring for toxicity recurrence. If it recurred, then the patient was shifted to another suitable agent.
The basic statistical analysis of cases and percentages were applied manually, and the mean survival time by Kaplan–Meier survival analysis was calculated using the Excel software (The Microsoft Corporation, Redmond, Washington, USA) (XLSTAT 2020.5.1.1077Z).
The procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation and with the Helsinki Declaration of 1964, as revised in 2013. This study was approved by the Ethics and Internal Review Board committee of the hospital (rec. number 2019-01-05). The waiver of patient consent was obtained owing to the retrospective nature of the study.
| Results|| |
The hospital received 80 newly diagnosed patients with CML who were treated between July 2002 and June 2020.
The patients age ranged from 16 years to 95 years, with a mean age of 41.6 years. The majority of patients [40 (50%)] were between the ages of 21 and 40 years. Only three (3.75%) patients were under the age of 20 years and three (3.75%) were above the age of 70 years. The male-to-female ratio was found to be 1.1 : 1 ([Figure 1]). The number of patients presented with abdominal discomfort was 29 (36.2%), fatigue was 20 (25%), abdominal discomfort and fatigue was 23 (28.7%), bleeding diathesis was three (3.75%), nonspecific skin lesions was two (2.5%), visual impairment was one (1.25%), acute compartment syndrome was one (1.25%), and priapism (with sickle cell anemia) was one (1.25%). One patient at diagnosis had advanced pancreatic carcinoma.
Phases of CML ([Table 1]) at the time of diagnosis showed 72 (90%) patients were in the CP, with four (5%) patients each in AP and BP.
Using the Sokal score ([Table 2]), 72 patients were found in the CP, with 22 (30.5%) in the low-risk category, 40 (55.5%) in the intermediate-risk category, and six (8.3%) in the high-risk group. The data for four patients were missing.
Treatment and toxicities
[Table 3] shows that the first-line treatment of the patients was as follows: imatinib 34 (42.5%), dasatinib 28 (35%), nilotinib 14 (17.5%), PEG-IFN 2 (2.5%), HU 1(1.25%), and no treatment 1 (1.25%). An elderly patient with pancreatic cancer and substantial comorbidities could not be given any treatment and died. Two patients were pregnant at the time of diagnosis. They were given PEG-IFN as the first-line treatment followed by TKIs (Imatinib in one and dasatinib in the other patient) after delivery. HU was given to 58 people before or at the same time as first-line TKI treatment.
|Table 3 First-line treatment of the patients and adverse events (AEs) of TKIs|
Click here to view
Regarding the toxicities of TKIs, 16 (20.5%) events of toxicities were noted as follows: imatinib in two (12.5%), nilotinib in five (31.25%), and dasatanib in nine (56.25%). As per the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, grade 1 was seen in 13 (81.2%) and grade 2 in three (18.7%) cases, of which one had skin itching and two had pleural effusion. There was no difference in the incidence of toxicity between chronic and advanced phases of CML.
Two patients later on developed nonhematological malignancies, malignant melanoma (after 24 months) and died shortly, and malignant gastrointestinal stromal tumor (after 18 months) of diagnosis of CML.
[Table 4] shows that CHR was noted in 96.2% of patients after 3 months of treatment. Molecular studies at 12 months of treatment revealed MMR in 61 (77.2%), partial response in four (5%), and failure in 14 (17.7%) patients. Overall, three (16.6%) patients were later on diagnosed with multiple TKI failure and referred for allogeneic stem cell transplantation.
The follow-up range was from minimum of 12 months up to 16 years. The mean survival period ([Figure 2]) in CP-CML in the study was calculated to be 15.4 years whereas in advanced phase CML was 4.7 years, and on comparison of the groups, it was found to be statistically significant (P=0.006).
|Figure 2 Kaplan-Meier survival analysis in chronic and advanced phase patients of CML (XLSTAT 2020.5.1.1077Z).|
Click here to view
Regarding treatment-free remission, four patients (5%) were in treatment-free remission, with one patient for 2 years and three for 4 years.
| Discussion|| |
CML is an MPN that develops as a result of a genetic alteration in a pluripotent hemopoietic stem cell. Patients in our study ranged in age from 16 to 95 years, with a mean age of 41.6 years, which is comparable to an Asian study that reported the mean age to be 39.3 years, with a range of 13 to 95 years . There was a male predominance, which was similar to our study. In another study conducted in Kingdom of Saudi Arabia (KSA), there were 142 males and 106 females, with a mean age of 38.2 years, but they included pediatric patients also in the study .
The patients with CML are predominantly seen in CP constituting 90–95% of all cases, with anemia and splenomegaly being the most common presentations . The majority (90%) of patients in the study at the time of diagnosis presented in CP with abdominal discomfort and fatigue. Other presentations included nonspecific skin lesions, bleeding diathesis, visual impairment, acute compartment syndrome, and priapism.
National Comprehensive Cancer Network (NCCN) Guidelines recommend determination of Sokal or Hasford risk status as part of the initial diagnostic and prognostic workup of CML . In our study, Sokal score was used, and patients with low-risk (30.5%), intermediate-risk (55.5%), and high-risk (8.3%) categories were found. Another study from India showed comparable distribution of cases with low risk (20.7%), intermediate risk (57.4%) high risk (21.8%) . Molecular responses are greater with second-generation TKIs across all risk groups, and high-risk groups may benefit more from newer agents for achieving early milestones and prevent progression to AP or BP . In clinical practice, patients with low-risk disease are treated with imatinib, whereas patients with intermediate-high risk disease are treated with second-generation TKIs .
High circulating neutrophil counts in CML might cause thrombotic problems, which can be minimized with cytoreductive treatment . HU before or concurrently with the start of first-line TKI treatment for cytoreduction was received by 72.5% of patients. The anti-CML effect of interferon alfa-2a may be achieved by dendritic cell activation, which may preferentially drive T-cell death of autologous Ph-positive cells but not Ph-negative cells . Pregnant patients who were diagnosed with CML were started upfront on PEG-IFN, and also if patients became pregnant during the course of TKI treatment, they were immediately shifted to PEG-IFN.
The patients in this study received first-generation (imatinib) and second-generation (dasatinib and nilotinib) TKIs. First-line dose adjustments, interruptions, and shifting to another TKI were observed usually as a result of adverse effects, lack of treatment responses, and poor compliance (noted mostly in case of imatinib). The risk score, patient’s age, the existence of comorbid conditions, ability to tolerate therapy, and TKI toxicity profile all had a role in the decision to use first-line TKI therapy (dasatinib, imatinib, or nilotinib) in a specific patient. Second-generation TKIs were given to younger patients, especially women, because achieving a deep and quick molecular response may allow TKI therapy to be stopped for fertility reasons. Older patients with comorbidities, especially cardiovascular, showed better response to imatinib . In our study, hematological remission was achieved in 96.2% of patients within 12 weeks of diagnosis and MMR in 77.2% patients at 12 months of treatment. The MMR rates for imatinib, dasatinib, and nilotinib were found to be 76, 90, and 91%, respectively, in the MD Anderson Cancer Center (MDACC) experience . Overall, eight (44.4%) of our patients who had suboptimal or failure of response were on irregular treatment owing to lack of compliance or financial constraints.
TKIs gave rise to the concept of a ‘functional’ or ‘operational cure,’ defined as the absence of disease progression and resistance, as well as long-term independence from any disease, sign or symptom in spite of presence of residual leukemic cells, and this can be achieved only with lifelong TKI treatment . However, multiple clinical trials have indicated that 40–60% of patients who obtain a deep and persistent reduction or eradication of remaining BCR-ABL1 transcripts (Deep Molecular Response) after several years of TKI treatment can safely stop taking their medication without relapsing ,. In our study, four patients were on treatment-free remission. The inclusion criteria for the EURO-SKI trial (ClinicalTrials.gov Identifier: NCT01596114) were used to determine eligibility to cease TKI . Outside of controlled clinical studies, treatment withdrawal is safe and effective. It should be considered in routine clinical practice if molecular monitoring is done on a regular basis in standardized laboratories and according to the criteria outlined in the European Society of Medical Oncology (ESMO) and National Comprehensive Cancer Network (NCCN) Guidelines .Imatinib has been linked to chronic weariness, hypophosphatemia, and a decrease in bone mineral density, as well as skin hypopigmentation. Hematologic adverse effects, platelet aggregation inhibition, and pleural effusion have been linked to dasatinib. Rash, headache, electrolyte imbalances, and lipase, glucose, and bilirubin elevation were more common with nilotinib than imatinib . The adverse events of TKI which were noted in our study were skin itching, neutropenia, pleural effusion, and bone marrow suppression ([Table 1]). Dasatinib contributed to maximum (56.2%) adverse events, notable being bone marrow suppression and pleural effusion. The majority of adverse events were grade 1, and treatment was continued either by dose reduction or discontinuation for a short period or shifting patient to another TKI. There was no death related to treatment. In another study done by Alenzi et al.  in KSA, imatinib was found to be safe. We had one patient in advanced phase (blast crisis) and three patients with multiple TKI failures who were referred to a larger center for allogeneic stem cell transplantation.
Mean survival time (Kaplan–Meier survival analysis) in CP in our study was calculated to be 15.4 years, whereas in advanced phase was 4.7 years. Since the introduction of imatinib therapy, the overall survival of newly diagnosed patients with CML has increased dramatically. In a study, the median survival in CP was 8.9 years, in AP it was 4.8 years, and in BP it was 6 months . This is a real-time study with many patients lost to follow-up, and the results obtained may not fully reflect the expected results in general population. Future studies in patients who are in treatment-free remission is very promising. They should be kept on follow-up and close molecular monitoring (every 6 months), which will throw light for consideration of CML as curable disease with the use of TKIs.
| Conclusion|| |
Our study revealed that patients with CML were predominantly middle aged with a slight male preponderance. Majority of patients presented in chronic phase, with the Sokal score in intermediate-risk category. Patients were treated upfront with TKIs, with a significant number receiving second-generation TKIs. First-generation had lesser adverse events as compared with second-generation TKIs, but these toxicities were mild.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]