Ask the experts
February 2011: Acute lymphoblastic leukaemia (ALL)
Welcome to the first Ask the Experts session for 2011. This month, we are joined by Dr Huib Buyck. Dr Buyck is a Consultant Haematologist at Wellington Blood and Cancer Centre, Wellington Hospital. He has an interest in malignant haematology and bone marrow transplantation.
Dr Buyck qualified from Otago University Medical School in1993, and commenced haematology training at Wellington Hospital in 1998. Dr Buyck has spent the last ten years working in various hospitals in London and has recently returned to New Zealand.
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Q: My daughter is being treated for ALL and is halfway through treatment, however, several children of the other families we have met have a treatment schedule over three years. I keep getting told this is because they are boys, are males harder to cure of cancer?
A: Historically, among children with acute lymphoblastic leukaemia, girls have tended to have a better outcome then boys. This can partially be explained by the fact that boys are more likely to be diagnosed with more serious type of leukaemia, called T-ALL, as opposed to the more common B-ALL, and that boys can also experience a relapse of their leukaemia in the testes. However, studies have also shown that boys with standard risk ALL have a higher rate of relapse or return of their leukaemia then girls after completion of treatment. Therefore it is standard approach worldwide for boys to receive three years (36 months) of treatment and for girls to receive only two years (24 months) of treatment.
Q: When my husband was first diagnosed he was tested for a “Philadelphia” chromosome. He is negative for this, which we initially thought was a good thing. However, we then discovered it would have been better if he was positive, as treatment would be shorter. I’m not really sure how this affects treatment, could you explain in simple terms, please?
A: Chromosomes are bundles of DNA, the genetic code that contains the blueprint for all cells. Within our normal cells we all have 22 pairs of chromosomes plus either an XX or XY chromosome. The “Philadelphia Chromosome” is an abnormal chromosome, resulting from the swapping over of material from chromosome 9 to chromosome 22. It is characteristically associated with a form of chronic leukaemia called chronic granulocytic leukaemia (CGL) and also acute lymphoblastic leukaemia (ALL). It can be detected when a sample of leukaemic cells, usually from the bone marrow is tested by a cytogenetic laboratory. The Philadelphia Chromosome is very uncommon in children with ALL, but becomes more common when ALL is diagnosed in adults, occurring in around a quarter of all cases. Unfortunately, ALL patients with the Philadelphia chromosome are less likely to go into remission or clearance of the leukaemic cell from the bone marrow after chemotherapy, and the leukaemia is more likely to come back after treatment, which is called relapse. Standard ALL therapy involves quite a long course of intensive chemotherapy to get the patient into remission, followed by maintenance, lasting a total of about two years. Because of the less favourable outcome of patients with Philadelphia positive ALL, alternative strategies to improve the outcome are being used, such as shorter but more intensive chemotherapy treatments, the use of drugs that specifically target the Philadelphia chromosome (such as imatinib and dasatinib) and the use of allogeneic stem cell transplantation (that is a transplant of stem cells or bone marrow cells either from suitable matched relative or an unrelated donor) which carries its own additional risks and complications.
Q: I absolutely hate IT chemo. It there anyway I could get around not having this part of my long and exhausting regimen, I’m over the side effects.
A: Without specific treatment to the so called central nervous system or CNS which is comprised of the brain and spinal cord, there is an extremely high risk of acute lymphoblastic leukaemia coming back within the CNS during or after treatment. The reason for this is that it is difficult for most chemotherapy drugs to enter the brain and spinal cord due to a protective barrier, called the blood brain barrier. Leukemic cells can pass through this barrier, and effectively hide from the treatment being given to the rest of the body. To prevent these cells from causing a relapse, we must give treatment that can penetrate the blood brain barrier and kill the leukaemic cells within the CNS. We do this by given intrathecal chemotherapy (injection of chemotherapy directly into the fluid lining the brain and spinal cord) as well as giving high doses of intravenous methotrexate as part of the chemotherapy regimen. Radiotherapy to the brain and spinal cord can also treatment leukaemia cells within the CNS but tends to be reserved for those patients with proven involvement of leukaemia within the brain or spinal cord, as it has significant potential adverse side effects. Unfortunately, intrathecal chemotherapy is a particular unpleasant aspect of ALL treatment. Sometimes this may be due to technical difficulties, such as getting the needle into the right place, or it may due to the pain and discomfort associated with the procedure. It is an important aspect of treatment, but if you are having difficulties tolerating the procedure, do discuss this with your consultant in case there are things that can be done to make it easier for you.
Q: My partner recently passed away from ALL and at the end he had what they called ‘CNS involvement’ although I don’t really remember anyone telling me what this actually meant. I would really like to know more about this to perhaps explain to me what happened and how he passed so quickly, can you explain?
A: As discussed in the answer to the previous question, the CNS is an abbreviation for central nervous system. This comprises the brain and spinal cord. The brain and spinal cord are lined by a tough membrane called the “dura” and between the brain and spinal cord, a clear fluid called the CSF (cerebrospinal fluid) circulates. When a patient is diagnosed with leukaemia, leukaemic cells are seen within the blood and/or bone marrow. However, leukaemic cells seen can also involve the brain and spinal cord, and this is what is referred to as CNS involvement. Symptoms may include headaches, nausea and vomiting, epileptic fits, visual disturbances or localised muscle weakness or loss of sensation although there may be no symptoms at all. Leukaemic involvement of the CNS can be diagnosed by taking a sample of the CSF and looking down a microscope. CNS involvement may be present at the time ALL is first diagnosed or it may occur at relapse. Unfortunately it is more difficult to treat CNS involvement by ALL, and includes high doses of chemotherapy in order for the chemotherapy to penetrate into the brain, direct injections of chemotherapy into the fluid lining the brain and spinal cord (called intrathecal chemotherapy), and radiotherapy. Involvement of the CNS does unfortunately predict for a significantly worse outcome.
Q: I’m in my 40s and was diagnosed with ALL last year. I’ve been told that if you’re a kid, ALL is the ‘good’ leukaemia to get, but if you’re an adult, it’s the ‘bad’ leukaemia. What is meant by this, and why are the odds different for adults and kids?
A: No leukaemia is “good” although the success rates of treatment vary according to type of leukaemia and age. Historically ALL in children was almost invariably fatal, but today around 80% of children and adolescents treated for ALL are cured of the disease. However, this is not without long and difficult treatment, and one cannot underestimate the personal hardship these children and their families must undergo. Furthermore, a small number of these children still do succumb to the disease, so we are constantly striving to improve the treatment and outcome through research and clinical trials. Unfortunately, the improvement in outcome for ALL in adults has not been as good as that for children, with long term survival still being less than half of that for children. There are a number of reasons for this, although admittedly we probably don’t have all the answers. A major factor is that adult ALL cells are more likely to carry more poor risk genetic mutations, such as the Philadelphia chromosome, and less likely to carry the good risk mutations, thus rendering the leukaemic cells more resistant to treatment and more likely to relapse. Furthermore, adults are less able to tolerate the intensive treatment that children undergo, as they experience more complications and often have other complicating medical problems. Treatment of ALL is constantly evolving as new information from research and trials becomes available, and hopefully in the future, success rates of adults will match for treatment of adults will match those of children.
Q: I have been diagnosed with ALL and was wondering what your thoughts are on complementary therapies? I will do what my specialist tells me but when I bring up the words ‘complementary therapies’ some people roll their eyes, I am curious.
A: Complementary medicines are therapies that complement conventional (or mainstream) therapy such as chemotherapy and radiotherapy. This is distinct from alternative medicines, which are used instead of conventional medicine and cannot be recommended. A broad range of therapies are included in the category of complementary medicine, such as yoga, massage, aromatherapy, and acupuncture. Complementary medicine is not intended to replace conventional therapy but may be integrated or added to treatment. While complementary therapies have not undergone the same degree of research and testing as conventional therapy, they can be beneficial to the individual by addressing not only the person’s physical needs, but also their emotional, psychological, social and spiritual needs. Whilst most complementary therapies do not have any significant adverse effects, some therapies, particularly if they involve taking supplements or other non-prescription medicines, can have potential adverse effects such as interfering with cancer treatment or causing toxicities. Therefore if you are considering taking any non-prescription medicines or supplements, it is imperative you advise the doctor that is looking after you.
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