A cancer of the bone marrow
A tumour disease that begins in the bone marrow, leukaemia, which means “white blood” in Greek, is characterised by a sudden, often massive proliferation of abnormal white blood cells. Bone marrow, located inside bones, is responsible for producing the various types of cells in the bloodstream. Leukaemia is thus a blood disease. However, because blood circulates throughout the organism, leukaemia frequently affects other organs and tissue as well, causing swelling (spleen, liver, lymph nodes), disrupting vital functions (lungs, kidneys, nervous and immune systems, blood clotting), blocking small veins and, in acute forms of the disease, inhibiting the production of normal blood cells.
For many patients, being diagnosed with leukaemia is deeply upsetting. They assume, often incorrectly, that they will have to undergo aggressive treatment and are at a high risk of dying of this cancer.
A varied group of cancers
There are many kinds of leukaemia. They differ according to the cells in which the disease originates and the type of mutation responsible for the malignant transformation. Newborns, children, adults and the elderly suffer from completely different types of leukaemia. In other words, a diagnosis of leukaemia may refer to any number of disorders, which vary in terms of their severity and pattern of development.
By analysing the patient’s tumour cells, doctors can estimate the severity of the cancer and make a prognosis. Statistically speaking, how likely is it to respond to treatment? What are the patient’s chances of recovering? More importantly, which treatment will be the most effective? The doctor’s objective, at this point, is to tailor the therapeutic regimen to each patient’s particular disease and individual characteristics.
There is no single prognosis for leukaemia, but rather a variety of prognoses depending on the type of leukaemia. Survival rates are as high as 80% for some types and closer to 50% for others. However, in some cases, the chance of recovery is still disappointingly low.
Treatments for leukaemia are constantly improving; many patients today stand a real chance of making a full recovery. The most widely used treatments are chemotherapy and, for certain types of leukaemia, haematopoietic progenitor cell transplantation (also known as bone marrow transplant).
New therapeutic approaches focus on reducing toxicity by more precisely targeting the cancer cells. By better understanding the mechanisms of malignant transformation, researchers have been able to develop drugs that block the negative effects of the genetic abnormality that causes a specific type of leukaemia. Other treatments widely used today include immunological approaches such as genetically modified antibodies, lab-cultured cells with anticancer properties, and vaccines.
Our ability to identify the genetic abnormalities that turn cells “leukaemic” and our understanding of how this occurs has progressed tremendously. However, what triggers the transformation is still unclear. To use a simple analogy, a car mechanic can generally identify which part caused the breakdown yet be unable to determine why the part became defective in the first place.