Chronic Myeloid Leukemia: Clinical and Laboratory Features At Presentation To a Referral Hospital In Southern Nigeria

Chronic Myeloid Leukaemia (CML) is one of the commonly diagnosed leukaemias and has been extensively studied, making it the first malignancy to have a constant identified mutation present which is relevant for diagnosis. CML is also a model for targeted therapy in the treatment of cancer.

Before the development of molecular techniques in diagnosis of CML, the clinical and laboratory parameters which included spleen size, total white blood cell (WBC) count, peripheral and bone marrow smears were essential in making a diagnosis of CML. In a developing country with less availability of molecular techniques of diagnosis, these parameters are still invaluable.

Here we present an eight year retrospective study of patients who were diagnosed with CML in our center, which is a tertiary referral center in the Niger-Delta zone of Nigeria.

We carried out a retrospective study of all CML cases who presented to the department of hematology at the University of Port Harcourt Teaching Hospital, Nigeria, from the year July 2004 – June 2012. Data were extracted from patients' records and included age, sex, absence/presence & duration of symptoms, full blood count and presence of Philadelphia chromosome. Other investigations done were erythrocyte sedimentation rate, uric acid, renal and liver function tests. Diagnosis of CML was made based on clinical features, full blood count, bone marrow aspirate and karyotyping for Philadelphia chromosome where available. The data generated from the above information were analyzed with SPSS statistical package software with results expressed in statistical tables.

A total of 105 haematological malignancies were seen between July 2004 and June 2012 of which 34 (32.4%) were CML. The mean age of presentation was 32.4 ± 16.2 years (range 19 - 75 years, median 36.5 years). There were 18 males and 16 females. The males had a lower mean age than the females (37.3 vs. 40.4 years) but this was not statistically significant (p=0.59), however the median age of males and females were the same (36 vs. 36.5 years). Males were only slightly more affected than females (male, female ratio 1.1 : 1).

No patient was asymptomatic at presentation. The commonest presenting clinical features were splenomegaly (91.2%), anemia (61.8%), fever (50%) and weight loss (50%). One patient had undergone a splenectomy. Seven (20.6%) presented as incidental findings while being investigated for other reasons due to development of complications such as renal failure, hearing loss, priapism, and had a higher mean WBC of 535.7 X 10⁹/L. All the patients presented with leucocytosis (mean 287 X 10⁹/L, range 72-1343 X 10⁹/L). There was no case of thrombocytopenia, but nine (26.5%) had thrombocytosis with a mean platelet count of 639.1 X 10⁹/L. Nineteen (55.9%) had a raised ESR.

Bone marrow aspirate findings of all patients typically showed increased cellularity and marked myeloid hyperplasia. Of the total 34 CML patients, 3(8.8%) presented in the accelerated phase and only 1(2.9%) in the blastic phase, majority presented in the chronic phase. Karyotyping for Philadelphia chromosome was done for 12(35.3%) and was positive in all cases.

CML represented about a third of the haematological cancers seen at our center. Our median age of presentation is lower than Caucasian values (32.4 vs ∼60 years) as reported by other African literature. The males presented at an earlier age than the women although this was not statistically significant. The clinical and laboratory parameters are comparable to international studies, though our patients had very high WBC count at presentation. We did not have any asymptomatic patient. This may be attributed to lack of awareness on the importance of routine medical checkup and evaluation in low resource countries. However, a larger multi-center study is required to corroborate these findings.

No relevant conflicts of interest to declare.