What is myelodysplastic syndrome – deletion 5q?
Deletion 5q is a rare form of Myelodysplastic Syndrome (MDS). For many people, it can remain stable for many years causing few symptoms. For others it may progress rapidly into a different subtype of MDS or transform into an acute leukaemia.
Deletion 5q is not very common. The World Health Organisation refers to it as Isolated del 5q however it is commonly known as Del 5q. In this type of MDS, the 5th chromosome is missing or has been deleted. It can involve any of the following, causing a decrease in the number of cells:
- refractory anaemia: a decrease in the number of circulating red cells resulting in anaemia. This is very common in Del 5(q) MDS
- refractory neutropenia: a decrease in a type of white blood cell called neutrophils. When these fall below normal limits, the patient is then considered ‘neutropenic’ and susceptible to infections
- refractory thrombocytopenia: a decrease in the number and quality of platelets, this is uncommon with Del 5(q) MDS.
What is the risk of MDS transforming to acute myeloid leukaemia (AML)?
MDS is classified as low risk, intermediate-1 and intermediate-2 or high risk according to the International Prognostic Scoring System (IPSS) at diagnosis. This system predicts the risk of your disease transforming into an acute leukaemia or your likely prognosis. The score is calculated on the bone marrow blast (immature) cell count, number of blood cell types affected and number and type of genetic changes on a cellular level.
Deletion 5q is classified as a low risk MDS as it rarely transforms into an acute leukaemia. Other subtypes of MDS may also contain deletion of chromosome 5. However, due to several complex chromosomal abnormalities they are not considered part of this subtype as they have a higher IPSS score. Signs that the disease may be progressing may include frequent infections, bleeding (e.g. from the nose or gums), bruising and the need for more frequent blood transfusions.
What causes MDS?
We do not know the cause of most cases of MDS. We do know however, that MDS occurs as a result of a gene mutation at a cellular level. Any incident that damages the genetic material of the body can potentially cause a mutation that in turn may contribute to the development of MDS. Examples of these incidents may include:
- pre-existing bone marrow condition
- cigarette smoking
- cytotoxic chemotherapy
- rare genetic or family history
MDS is not infectious and cannot be transmitted from one person to another.
Who does del 5q affect?
Del 5q occurs more often in women over the age 67.
How is del 5q treated?
Del 5q is generally managed using the “Watch and wait” approach with supportive care provided if or when required.
Watch and wait involves regular monitoring of blood and general health. No intervention is needed unless the person begins developing signs and symptoms of the disease indicating it is progressing.
Supportive care refers to the administration of therapies to alleviate symptoms of the disease or to manage the side-effects of the therapies. Supportive care is aimed at improving the person’s quality of life and may even extend the person’s life. Supportive care therapies may include:
- blood and platelet transfusions – MDS may lead to a reduction in the number of circulating blood cells. Transfusing blood products may be required to alleviate symptoms and to improve overall health.
- antibiotics – people who have a reduced immune system from MDS may be at an increased risk of developing severe infection. Antibiotics can prevent a simple infection becoming life-threatening.
- iron chelation therapy – red blood cells contain iron and when people with MDS require ongoing blood transfusions, they can build up excess iron in their bodies (iron overload) which can be damaging to body organs. Therapies may be administered that help remove the excess iron from the body.
Supportive care may be the most appropriate treatment for older people or those with other health problems. This is mainly due to this group of people being unable to tolerate the stronger treatments used for MDS. Supportive care does not aim to treat the disease but can help alleviate symptoms such as shortness of breath and symptoms of bruising or bleeding.
Lenalidomide (Revlimid) is used widely to treat MDS with deletion 5q. The exact mechanism of how this works is unknown. People who have a good response to treatment with Revlimid may never need a blood product transfusion again. Revlimid reverses anaemia in many low risk patients. One of the side effects of this therapy may be low blood cell counts initially leading the individual to utilise supportive care. Lenalidomide is yet to be reimbursed in Australian by the Medicare system. People are currently only able to access this drug through clinical trials or by paying for it themselves.
Is there a cure for MDS?
For younger people, a stem cell transplant is an option and is the only known cure for MDS. Your doctor will discuss treatment options you and your loved ones and gain your consent prior to commencement.