Acute lymphoblastic leukaemia (ALL) is a form of cancer that affects the cells in the bone marrow, the soft material inside your bones. The particular cells affected are lymphocytes, a type of white blood cell vital for your immune system. Lymphoblasts (known as blasts) are the immature cells that normally develop into lymphocytes in your bone marrow. When people have ALL this process goes wrong, the leukaemia blast cells reproduce too quickly and do not mature properly. The leukaemia cells build up in the bone marrow and prevent normal cells from developing. ALL develops quickly so prompt diagnosis and treatment is essential.

There is no single absolute cause for ALL. The factors below may affect a person’s chance of getting ALL

  • Age – ALL is the only type of leukaemia that happens more often in children than adults. It is less likely in middle age and then can occur more often again in older people.
  • Gender – it is slightly more common in men than in women.
  • Family History – ALL doesn’t usually run in families, only in rare cases does this occur.
  • Radiation – radiation in high doses can lead to leukaemia, but this is very rare.

It is important to remember that none of your lifestyle choices have contributed to this condition.

Symptoms of ALL can occur over a number of weeks and occasionally months. These symptoms are mostly due to the bone marrow being overwhelmed with leukaemia cells, leaving no room for the production of normal blood cells:

Red Blood Cells. These contain haemoglobin, the protein that carries oxygen around the body, and their decrease can cause:

  • Fatigue - tiredness that is unusual and that does not improve with rest/sleep
  • Breathlessness - becoming short of breath when undertaking standard activities of daily living (like climbing the stairs)
  • Dizziness - when standing up from a seated position or when standing for long periods
  • Headaches - when expending energy

Platelets. These are involved in helping the blood to clot and their reduction may result in:

  • Bruising - more than normal without any significant trauma
  • Bleeding - this can be from your gums after brushing, from your nose and for women their menstrual period can be heavier than they are used to
  • Petechiae - small red or purple spots on the skin, which are caused by bleeding from broken capillary blood vessels
  • Bleeding from the bowel - black, tarry stools

White Blood Cells. These are normally involved in fighting infection and their decrease may lead to:

  • Infection – recurrent or severe infections such as urinary tract infections, pneumonia, cellulitis (skin infections) or gastroenteritis
  • High fever
  • Excessive sweating – in the night or day
  • Viral type symptoms that do not improve over some weeks

Other symptoms:

  • Weight loss – due to high metabolism
  • Enlarged lymph glands – for example in the neck, groin or armpits
  • Night sweats – these may be due to infection or directly caused by leukaemia cells

There are different subtypes of ALL and the treatment you have may differ depending on which type is diagnosed. There are different types of lymphocytes known as B cells and T cells. ALL develops more frequently in cells that would normally have developed into B-cells (B-cell ALL) but also occurs in T-cells.

Philadelphia positive ALL is seen in about one in four people who are diagnosed with ALL. This is when the leukaemia cells divide more often and live longer than usual due to a specific fault in the leukaemia cell chromosomes (called the Philadelphia chromosome after the city in which it was discovered). The Philadelphia chromosome leads to the production of an abnormal protein that stimulates the leukaemia cells to grow excessively fast. This is important to diagnose as treatment for this type of ALL includes the use of a specific drug to block the action of this protein.