Acute Lymphoblastic Leukemia vs. Chronic Lymphocytic Leukemia

Acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL) are two types of blood cancer that affect specific white blood cells produced by the bone marrow, called lymphocytes. ALL is also called acute lymphocytic leukemia.

CLL is the most common form of leukemia cancer affecting adults. ALL primarily affects children, although it can occur in adults. Learn more about the differences between ALL and CLL, including symptoms, causes, diagnosis, and treatment.

Symptoms 

Both acute lymphocytic leukemia and chronic lymphocytic leukemia produce similar symptoms, including:

• Fatigue and weakness
• Fever
• Night sweats
• Frequent infractions
• Easy bruising and bleeding
• Weight loss
• Swollen lymph nodes 
• Abdominal fullness 
  

Children with ALL may appear pale and experience abnormal shortness of breath when playing. Additionally, ALL can also cause pain in the joints or bones.

It can be challenging to distinguish between the two cancers. However, the person’s age can provide an important clue. ALL is more common in children, and CLL is more common in adults. In fact, CLL rarely affects people under the age of 30. 

A critical difference between ALL and CLL is that ALL is an acute form of leukemia. This means that it progresses much more rapidly than CLL. Also, in the majority of the cases, immature white cells (blasts) are seen on the peripheral blood smear test of patients with ALL but not on the peripheral smear of patients with CLL.

Causes 

ALL and CLL are very similar since they both start in the lymphocytes of the bone marrow. In most cases, these types of cancer stem from acquired mutations (changes in the genetic code that happen after conception). However, they do have slightly different risk factors.

Acute Lymphoblastic Leukemia

Experts don’t quite know exactly what causes ALL. However, some potential risk factors include:

• Having a sibling who has a history of leukemia
• Certain genetic conditions such as Down syndrome, Li-Fraumeni syndrome, neurofibromatosis, Fanconi anemia, and ataxia-telangiectasia
• History of radiation or chemotherapy treatment 
• Taking immune-suppressing drugs after an organ transplant
• Being a child
• Being over the age of 70
• Being male
• Being Hispanic or White 
• Benzene exposure
• Viral infections such as the Epstein-Barr virus (EBV)
  

According to the American Cancer Society, exposure to electromagnetic fields, smoking, and certain chemicals have not been proven as risk factors for ALL, although research continues.

Chronic Lymphocytic Leukemia

Experts also aren’t sure what exactly causes CLL, but some risk factors may include:

• Exposure to the chemical Agent Orange (used to clear vegetation in the Vietnam War)
• Having a close family member who also has CLL
• Being older than 50
• Being male
  

Diagnosis 

Both ALL and CLL are typically suspected after abnormal blood test results. Additional testing may include:

• Further blood tests
• Imaging tests
• Spinal tap
• Bone marrow biopsy
• Genetic testing
  

ALL Testing

Doctors may check for the following in lab samples when looking for ALL:

• Abnormal levels of lymphoblasts (immature lymphocytes)
• Low levels of red blood cells (which carry oxygen to the tissues) or platelets (cells involved in clotting)
• Whether the blood is clotting properly
  

CLL Testing

Doctors may check for the following in lab samples when looking for CLL:

• Abnormally high levels of lymphocytes
• Low levels of platelets and red blood cells
• Whether you have sufficient antibodies to combat infection
  

Treatment 

Treatment for ALL and CLL share some similarities. However, because they may affect different age groups, these cancers require different treatment approaches.

ALL Treatment

The treatment approach for ALL depends on a person's risk group. Very high-risk individuals usually receive more aggressive treatment. 

Treatment for ALL involves multiple phases:

• Remission induction: This phase is intended to kill cancer cells in the blood and bone marrow and induce remission.
• Consolidation: Once the cancer is in remission, this step aims to kill any remaining cancer cells.
• Maintenance: This phase also aims to kill remaining cancer cells that may cause a relapse. Treatment at this stage may involve lower doses.
  

Standard therapies for ALL include:

• Chemotherapy: This therapy kills rapidly-growing cells and reaches throughout the body. It is usually given by intravenous infusion (into a vein).
• Radiation: This therapy uses high-energy waves to destroy cancer cells, usually aimed at specific areas of the body, such as when cancer has spread to the brain.
• Chemotherapy with stem cell transplant: More aggressive chemotherapy kills cancer cells, but it also damages the patient's bone marrow, where blood cells are produced. The bone marrow is then restored with a stem cell transplant.
• Targeted therapies: These drugs attack specific types of cancer cells.
  

CLL Treatment

Treatment for CLL also depends on the cancer stage and whether the person has any other conditions. In some cases, doctors will recommend a wait-and-see approach since CLL is a slow-growing cancer.

Standard treatment options for CLL may include:

• Chemotherapy
• Radiation therapy
• Targeted therapies 
  

Doctors may also recommend stem cell (bone marrow) transplants in younger people.

Prevention 

There is no known way to prevent either ALL or CLL. Likewise, there’s no way to change your lifestyle to prevent either of these cancers. Avoiding certain chemicals may lower your risk, but chemical exposure isn’t a risk factor in all CLL or ALL cases. 

Summary 

ALL and CLL are both cancers that affect the bone marrow and blood. ALL is an acute form of leukemia that progresses rapidly, while CLL is slow-growing. Doctors treat ALL more aggressively than CLL because it spreads more rapidly. In some cases, they may opt for a wait-and-see approach with CLL. 

A Word From Verywell 

Whether you have ALL or CLL, getting a cancer diagnosis can feel overwhelming. However, knowing what you’re up against can help you be better prepared for treatment, which may improve your outcomes in the long term. Also, seek support from friends and family or resources such as support groups.