Welcome to the sixteenth part of a series on Hemato-oncology.
Question: Dr. Chiragbhai, thank you for explaining to us about treatment of ALL – Acute Lymphoid Leukemia. It was good to know that this leukemia has a cure rate as high as 60-90%.
Now, can you tell us about the Chronic Leukemias?
Answer: Chronic leukemias include mainly CML i.e. Chronic Myeloid Leukemia and CLL i.e. Chronic Lymphoid Leukemia. They behave very differently from acute leukemias, and are mostly treated as outpatient, often with tablets. In fact, most such patients are not ready to believe that they have “leukemia” and yet we are giving them very good prognosis.
Que: Yes, Leukemia word sounds so scary. How do the chronic leukemias present?
Ans: First, we will talk about CML i.e. Chronic Myeloid Leukemia, since it is the most exciting disease for hematologists. This is the disease where underlying specific genetic abnormality i.e. Philadelphia chromosome, was first identified many years ago. Also, CML is the first disease to have a truly targeted therapy, based on this specific genetic defect i.e. drug called IMATINIB, which revolutionized treatment of CML.
CML results from a stem cell defect i.e. development of a genetic translocation from chromosome 9 to 22, resulting in a fusion gene known as BCR-ABL. Product of this fusion gene is a protein, with very high tyrosine kinase activity. This leads to uncontrolled cell proliferation, resulting in very high counts.
Que: That is really exciting. We used to study about Philadelphia chromosome in medical college, so now we have a medicine based on this knowledge, targeted therapy.
Ans: Yes, and the treatment is also completely different from what we studied then. Anyway, as most people are aware, CML presents with minimal or no symptoms. Patients frequently have high white blood cell count detected on routine examination. Those with more long standing disease present with large spleen and related abdominal discomfort or early satiety, low grade fever, fatigue. These patients frequently have very large spleens, going up to umbilicus. Most patients have high platelet counts as well, however hemoglobin is generally normal. Peripheral smear shows a picture of “bone marrow in blood” i.e. presence of various early cells in blood, such as normoblasts, myelocyte, metamyelocyte, promyelocyte, and occasional blasts, increased basophils.
Que: What causes CML?
Ans: Most cases are not related to any known etiology. However, exposure to atomic radiation increases risk, as noted in Hiroshima and Nagasaki experience.
Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 98243 12144, 98988 31496
Diplomate American Board of Oncology and Hematology. Ahmedabad. firstname.lastname@example.org
Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad. www.shyamhemoncclinic.com