Precursor B-cell acute lymphoblastic leukemia is a fast-growing leukemia that affects early B cells in bone marrow. It’s both more common and has a better outlook in children.
Leukemia is a type of cancer that affects white blood cells. When you have leukemia, these cells, which are formed in your bone marrow, begin to grow and divide uncontrollably.
There are several types of leukemia. Acute lymphoblastic leukemia (ALL) is a fast-growing leukemia that affects early forms of B cells and T cells called lymphoblasts.
Precursor B-cell acute lymphoblastic leukemia, also called pre-B-ALL or simply B-ALL, affects immature B cells. These are early forms of B cells that haven’t fully developed yet.
Continue reading to learn more about pre-B-ALL. We’ll explore topics such as its causes and risk factors, symptoms, diagnosis and treatment, and outlook.
Pre-B-ALL happens as a result of genetic changes in immature B cells. These changes prevent the cells from fully developing into B cells and can also lead them to start growing and dividing out of control.
The known risk factors for ALL, including pre-B-ALL, include:
- Age: ALL is
more common in children and in adults over 50 years old. - Sex: People assigned male at birth are more likely to develop ALL.
- Genetics: Certain genetic conditions, such as Down syndrome, Fanconi anemia, and Li-Fraumeni syndrome, can
increase the risk of ALL. - Environmental exposures: Exposure to radiation, chemotherapy, or hazardous chemicals such as benzene may
raise the risk of ALL.
As leukemia cells build up in your bone marrow, they crowd out other blood cells. This leads to lower levels of healthy red blood cells, white blood cells, and platelets — and to the symptoms of pre-B-ALL.
Red blood cells carry oxygen to your organs and tissues. A low red blood cell count can cause anemia, which leads to symptoms such as:
- fatigue
- weakness
- shortness of breath
- dizziness or lightheadedness
- pale skin
A low level of white blood cells can affect your ability to respond to infections. That means you may have more frequent infections or recurring fevers.
Platelets help your blood to clot. A low platelet count can cause you to bruise more easily and have frequent nosebleeds, bleeding gums, or heavier periods.
Additional signs and symptoms of pre-B-ALL can include:
- reduced appetite
- unintended weight loss
- night sweats
- swollen lymph nodes
- enlarged spleen or liver
- chest or abdominal pain
- bone or joint pain
The effects of pre-B-ALL can lead to a variety of complications, including serious bleeding events and infections that are difficult to treat.
It’s also possible for the cancer to spread into other areas of your body, such as your brain and spinal cord. This can lead to symptoms such as headaches, issues with vision or balance, and seizures.
Tumor lysis syndrome is a serious and potentially life threatening complication of pre-B-ALL treatment. It happens when a high number of cancer cells die at once and release their contents into your bloodstream.
The symptoms of tumor lysis syndrome can include:
In general, ALL is more common in children than in adults. In fact, it makes up
Pre-B-ALL is the most common type of ALL in children, making up more than 80% of diagnoses. The remaining percentage of ALL diagnoses affect immature T cells.
The outlook for ALL is better in children than in adults. The
If you or your child has symptoms that are consistent with ALL, make an appointment with a healthcare professional to discuss them.
ALL symptoms can be nonspecific, which means that they can resemble those of more common health conditions. A good general rule is to look out for unexplained symptoms that are persistent or continue to get worse over time.
After getting your medical history and doing a physical exam, a healthcare professional can use the following tests to diagnose pre-B-ALL:
- a complete blood count (CBC) to look at the levels of various blood cells
- a bone marrow aspiration and biopsy to check for the presence of leukemia cells
- additional blood tests such as a comprehensive metabolic panel, coagulation tests, and tests of liver and kidney function to assess overall health and rule out other conditions
If healthcare professionals find leukemia cells during the analysis of your bone marrow, they can perform the following tests to further characterize the cells:
- immunophenotyping, which helps determine whether the leukemia is affecting B cells or T cells
- genetic tests, which look for specific genetic changes in the leukemia cells
It’s also possible that healthcare professionals will do imaging tests and an analysis of cerebrospinal fluid to see whether pre-B-ALL has spread to other parts of your body, such as your brain.
Chemotherapy is the main type of treatment that’s used for pre-B-ALL. It’s typically divided into three phases:
- Induction: The induction phase uses a combination of several drugs with the goal of establishing remission of pre-B-ALL.
- Consolidation: The consolidation phase is more intense and aims to kill any leukemia cells that may be left in your body after the induction phase.
- Maintenance: If pre-B-ALL is in remission after the induction and consolidation phases, the maintenance phase helps keep it in remission and prevent a relapse.
You may receive additional treatments to address or prevent the spread of pre-B-ALL to your brain and spinal cord, including:
- intrathecal chemotherapy, which is given directly into your cerebrospinal fluid
- high dose chemotherapy given intravenously (directly into a vein)
- radiation therapy given directly to your brain and spinal cord
Depending on the specific characteristics of the cancer, how it responds to initial treatment, and your age and overall health, other potential treatments may be recommended. These include:
The outlook for pre-B-ALL can depend on many factors, such as:
- your age at diagnosis
- your white blood cell count at diagnosis
- the types of genetic changes your pre-B-ALL has
- whether the cancer has spread to your brain or spinal cord
- how the cancer responds to initial treatment with chemotherapy
- whether the cancer stays in remission after treatment or relapses
Children with ALL, including pre-B-ALL, have a better outlook. Researchers have observed that the long-term survival rate for children with ALL is nearly 90%.
A 2021 study looked at survival rates for ALL in different age groups. In the years 2010 through 2017, the estimated 5-year survival rates for adults with ALL were:
- 59% for adults 20 to 39 years old
- 43% for adults 40 to 59
- 29% for adults 60 to 69
- 13% for adults 70 and older
There’s currently no known way to prevent pre-B-ALL. That’s because it’s unclear what exactly drives the disease to develop in the first place.
However, because pre-B-ALL grows quickly, the outlook is best when it’s diagnosed early. For this reason, be sure to see a doctor if you have concerning symptoms that are consistent with those of pre-B-ALL.
What is the difference between B-ALL and pre-B-ALL?
B-ALL and pre-B-ALL are essentially
After 2008, the World Health Organization (WHO) classified pre-B-ALL as B-ALL. ALL that affects mature B cells is called Burkitt leukemia.
What is relapsed B-cell acute lymphoblastic leukemia?
Leukemia is referred to as relapsed when it comes back after treatment. An estimated 10% to 15% of children who are treated for ALL experience a relapse.
Pre-B-ALL is a type of fast-growing leukemia that affects early B cells. The buildup of leukemia cells in your bone marrow can lead to anemia, an increased infection risk, and easy bruising or bleeding.
Pre-B-ALL is more common in children than in adults. It also has a better outlook when it’s diagnosed in childhood. The main treatment for this type of leukemia is chemotherapy.
As with any cancer, the outlook for pre-B-ALL is better when the disease is diagnosed and treated early. For this reason, it’s important to see a healthcare professional if you develop concerning symptoms that are consistent with those of pre-B-ALL.