What You Need To Know About Chronic Myeloid Leukaemia

What You Need To Know About Chronic Myeloid Leukaemia - Blood comprises red blood cells, which transport oxygen; white blood cells, which fight infection; and platelets, which prevent bleeding.

The stem cells in the bone marrow differentiate into two categories of white blood cells: myeloid cells, which fight bacterial and parasitic infections and prevent tissue damage from spreading; and lymphocytes, which fight viral infections.

Leukaemia is a cancer of the white blood cells. It can be acute or chronic. The former progresses rapidly, and the latter, gradually.

Both types are classified according to the type of white cell involved i.e. acute myeloid and lymphoblastic leukaemia; and chronic myeloid and lymphocytic leukaemia.

Chronic myeloid leukaemia (CML) is due to a mutation in the bone marrow’s stem cells, resulting in the increased production of immature white blood cells (blast cells).

In most CML sufferers, there is swapping of a segment of the DNA of chromosomes 9 and 22, causing a longer chromosome 9 and shortened chromosome 22 (Philadelphia chromosome), which result in the increased production of blast cells.

The cause is unknown, but CML is not inherited or transmissible to the sufferer’s child(ren).

The large numbers of blast cells lead to a decrease in normal red blood cells and platelets.

Although CML can affect any age, most sufferers are older adults. Other risk factors are male gender and radiation exposure.

Features of CML

There are no symptoms in the early stages of CML, which may be detected following tests for other symptoms.

Its features develop slowly over many years. They include tiredness, weight loss, night sweats, breathlessness, fever, easy bruising from various sites, bone and joint pain, frequent infections, and enlargement of the liver and/or spleen.

The complications of CML include weakened immunity and bleeding.

Weakened immunity is due to CML itself or the side effects of treatment. This leads to an increased risk of infection and an increased intensity in any infection that develops.

Easy bruising and bleeding from various body sites such as the nose, gums and skin, are common.

The initial diagnosis is made from blood tests. An increase in blast cells or a low blood count would lead to a referral to a physician or a specialist in blood conditions (haematologist).

A bone marrow biopsy confirms the diagnosis. This is carried out under a local anaesthetic in the skin on the back of the hip bone with a thin needle inserted to remove a sample of bone marrow, which is then examined for cancer cells.

If present, the type of leukaemia will be determined.

There may be some bruising and tenderness afterwards.

Additional tests done to detect the extent of CML in order to facilitate decision-making on treatment include computerised tomography (CT) scan, x-rays and other tests.

CML is classified into three phases according to the percentage of blast cells in the bone marrow or blood, i.e. chronic, accelerated and blast, to help predict the patient’s outlook.

Managing CML

Treatment depends on factors that include the patient’s age, CML phase and preference.

The treatments used include chemotherapy, interferon, radiotherapy, surgery and stem cell transplant.

The standard treatment for chronic phase CML is a tyrosine kinase inhibitor (TKI) like imatinib, nilotinib, dasatinib or bosutinib.

If the first medicine stops working or it never worked well, the dose may be increased or one of the other TKIs might be tried.

Ponatinib is an option after all the other TKIs have been tried, or if the leukaemia cells later develop a mutation.

The response to treatment is monitored with blood tests and testing for the Philadelphia chromosome with criteria for different response types. The response rate is 70% or more after a year.

As it is often unclear whether there is cure, most patients continue on TKI indefinitely.

If there is no response to the initial treatment, the options are to increase the dose, switch to another TKI, interferon, chemotherapy or stem cell transplant.

The cells build up more quickly in accelerated phase CML, causing symptoms with new gene mutations rendering treatments less effective. Its treatment depends on what treatments the patient has already had.

In general, the treatment is similar to chronic phase CML, but there is less likelihood of long-term response to any treatment.

The treatment options include increasing the dose, switching to another TKI, interferon, chemotherapy or stem cell transplant.

The cells become more abnormal in blast phase CML with the disease acting like an acute leukaemia, with higher blood counts and symptoms appearing or becoming more severe.

High dose imatinib or newer TKIs may be helpful. Standard chemotherapy used in acute myeloid leukaemia will bring about remission in about one in five patients, but is short-lived.

Because most patients cannot be cured, palliative treatment to relieve symptoms, rather than cure, is important, such as radiation to shrink an enlarged spleen, or reduce bone pain or chemotherapy to relieve symptoms.

A stem cell transplant may cure some patients. The transplant helps the re-establishment of healthy stem cells by placing healthy leukaemia-free stem cells in the bone marrow.

Prior to a stem cell transplant, high dose chemotherapy, and possibly radiotherapy, is given to destroy the leukaemia-producing bone marrow.

Subsequently, infusions from a compatible donor are given through a tube in a vein.

Some CML patients choose to enrol in clinical trials involving experimental treatments or new combinations of known treatments.

CML is often a slow-growing cancer. Many people live long lives with it, although it may be difficult to get rid of.

Upon diagnosis, the attending doctor will come up with a treatment plan.

One should always feel free to consult another doctor for a second opinion if one feels so.

Emotional support from family and friends would be helpful in managing the illness.