CML
The history of this disease is very impressive. CML has been known to medical science for almost a century. The cause of this illness is unclear. However, survivors of atomic disasters in Japan had a significantly higher risk of developing CML, as well as individuals exposed to any other form of external irradiation.
It was one of the very first illnesses for which a unique chromosomal abnormality was discovered (known as Philadelphia Chromosome). It is also one of the first cancers that responded very well to biological treatment with Interferon. Some of the most impressive results of bone marrow transplantation come from patients with CML.
Approximately, 3,000 to 5,000 Americans develop CML each year. It always involves the blood and bone marrow, as well as the spleen and liver. CML is twice as frequent in men as in women. It is more commonly seen after age 50 but can be seen in any age group, even in children. This disease is due to overproduction of myeloid cells.
Signs and Symptoms
The disease has three distinct phases:
Chronic Phase: In up to 40% of patients, CML is diagnosed incidentally through a routine blood test. Patients may not show any signs for many months. As the disease progresses, it can cause any of the following problems:
- Fatigue, weakness
- Loss of appetite,
- Fever
- Weight loss
- Night sweats
- Enlargement of the spleen, which can be painful
- Enlargement of the liver
- Anemia
- Low platelet count
- Frequent infections
- In rare cases, patients with very high white blood count may present with Hyperviscosity syndrome.
Accelerated Phase is a transition phase from chronic to blastic phase. The diagnosis is made from rapid changes in blood counts and the picture of bone marrow. Some patients may experience a greater degree of severe symptoms, such as high fevers, accelerated weight loss, rapid enlargement of spleen, etc.
Blastic phase is when CML transforms into an acute leukemia, at which point the patient will display more symptoms and may suffer from any or all of acute leukemia complications.
Diagnosis
This diagnosis is often made incidentally, when an elevated white blood count is noticed in a routine blood workup. A bone marrow test will establish the diagnosis. The white blood count may be extremely high. An evaluation of blood and bone marrow under microscope will lead to a diagnosis. The confirmatory test is detection of Philadelphia Chromosome.
Staging
Refers to the extent of the disease and is a very good guideline for a plan of treatment which will affect the outcome of CML. The best indicators for this purpose are stages of the illness:
- Chronic Phase
- Accelerated Phase
- Blastic phase
Treatment
Gleevec is the first line treatment option for CML in almost all phases. This drug can induce durable remissions is great majority of patients. Other treatment options include Bone Marrow Transplantation (BMT) when indicated and other chemotherapy agents such as Busulfan, Hydrea and Interferon.
CML can be cured in up to 70 percent of patients who undergo Bone Marrow Transplantation (BMT). Upon establishing a diagnosis, if the patient is deemed to be a candidate for BMT, a search for a donor must be initiated. If an identical twin or a matching sibling is available, a BMT should be considered.
For patients who do not have a sibling donor, a search for an unrelated donor must be initiated. Transplants for CML patients using an unrelated donor are best performed at the initiation of the accelerated phase. Preparation for BMT takes a few months. Meanwhile patients are treated with medications to control the illness.
Patients who transform into Acute Leukemia are treated with proper Acute Leukemia regimens.
Prognosis
Patients who undergo BMT have a very good prognosis. This is the only modality that can cure and eradicate CML. Treatment modalities other than BMT may control the disease for a few years. CML will, however, gradually transition into a higher stage of acute leukemia, which is much more difficult to treat.
