Treatment of chronic myeloid leukemia aims at correcting blood counts in three months, clearing bone marrow of the cells containing Philadelphia chromosome by 12 months and taking the patient to a stage where the leukaemia can only be detected by a very sensitive molecular test by 18 months.
Early treatments for CML
Chronic myeloid leukemia is effectively treated early with specific targeted therapies. This includes a group of drugs called the tyrosine kinase inhibitors that includes drugs like Iamtinib, Dasatinib, Nilotinib etc.
Imatinib is started soon after diagnosis of CML. In responsive cases Imatinib successfully slows the progression of the disease. These tablets are taken every day for life and have been very effective.
It is usually given as soon as a diagnosis is made because it can slow the progression of the cancer and can effectively prevent the condition reaching the accelerated or advanced phase.
Imatinib is a type of tyrosine kinase inhibitor. It blocks the protein called tyrosine kinase. Normally tyrosine kinase helps to stimulate the growth of cancer cells. Blocking tyrosine kinase reduces the production of abnormal white blood cells.
It is available as pills and side effects include nausea, vomiting, swelling in the face and lower limbs, rash, diarrhea and muscle cramps.
10 to 40% of CML patients who take imatinib become resistant to its effects and need an alternative therapy. These patients can be treated with Nilotinib. Nilotinib works in a similar way to Imatinib by blocking tyrosine kinase.
Side effects include vomiting, bone pain, abdominal pain, hair and appetite loss, sleep problems, dry skin, night sweats, numbness, tingling and dizziness.
Treatment for advanced cases of CML
Advanced cases of chronic myeloid leukemia are treated using chemotherapy agents useful against cancers.
Chemotherapy has a range of side effects including bone marrow suppression, anemia, bleeding tendencies, infections, hair and appetite loss, nausea and vomiting, tiredness, infertility etc.
Bone marrow and stem cell transplants
The next step in treatment is with bone marrow and stem cell transplants. This method can offer a cure in chronic leukemia, however, it is only suitable for some patients.
The person is given high dose chemotherapy prior to the transplant to kill off cancer cells. Thereafter the blood cells from the donor are injected into the person so that he or she is free from the cancer.
Bone marrow transplants are fraught with risks and side effects and potential complications. Transplantations have better outcomes if the donor has the same tissue type as the person who is receiving the donation.
A sibling or a twin is often the best match. In most cases of chronic leukaemia especially among elderly patients, the potential risks of transplantation far outweigh any benefit.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)