Skip to main content

Leukemia Stages & Classifications

BRCC-Cancer-Sub-Banner-Leukemia-01

Leukemia is not staged the same way as many solid tumors. Instead of focusing on tumor size and spread, staging systems for leukemia look closely at blood cell counts, bone marrow involvement, genetic features, and how quickly the cancer cells are growing. Understanding the type and classification of leukemia directly guides the treatments your Blue Ridge Cancer Care team recommends.

There are four primary categories of leukemia, each with its own classification system.

Phases of Acute Lymphocytic Leukemia (ALL)

All Uses Disease Phases Instead of Stages

Acute lymphocytic leukemia is not typically divided into numbered stages like solid tumors. Instead, acute lymphocytic leukemia is classified based on disease status and risk factors.

At diagnosis, ALL is generally considered systemic, meaning it involves the bone marrow and often the blood. Because of this, traditional staging (Stage I–IV) is not useful.

Disease Phases in ALL

Acute lymphocytic leukemia is commonly described in terms of response to treatment:

Remission
Remission means that leukemia cells are no longer detectable in the bone marrow (typically fewer than 5% blast cells), blood counts return to near normal, and symptoms improve.

Minimal Residual Disease (MRD)
Even when remission is achieved, small numbers of leukemia cells may remain. Sensitive testing can detect MRD, which helps guide further therapy.

Relapsed or Refractory ALL
Relapsed ALL occurs when the leukemia returns after remission. Refractory ALL means the disease did not respond adequately to initial treatment.

Prognostic Outlook for Patients with ALL

In addition to the phase of leukemia, the oncologist will consider these factors when assessing the patient’s most likely outcome of treatment.

  • Age at diagnosis - The older the patient, the less favorable the outcome
  • White blood cell count - Patients with lower white blood cell counts at diagnosis tend to have better outcomes
  • Genetic and chromosomal changes - Certain genetic changes identified in the cancer cells will tell the oncologist more about how well the patient will respond to treatments. Some genetic changes are less likely to respond to treatment.
  • Response to early treatment - People whose leukemia goes into remission within 4-5 weeks tend to have more positive outcomes.

Staging for Chronic Lymphocytic Leukemia (CLL)

Rai Staging System for CLL

CLL is staged using systems that reflect how far the disease has progressed in the blood, bone marrow, and lymphatic system. The Rai system is most commonly used in the United States.

Stage 0
There is an increased number of lymphocytes (white blood cells) in the blood, but no other symptoms or organ involvement.

Stage I
Lymphocytosis (too many lymphocytes in the blood) is present along with enlarged lymph nodes. Liver and spleen are normal, as well as red blood cells and platelets.

Stage II
In addition to lymphocytosis, there may be enlargement of the spleen and/or liver. Lymph nodes may or may not be affected. Red blood cell and platelet counts are near normal.

Stage III
In addition to lymphocytosis, anemia develops, meaning red blood cell levels are low but platelet levels are normal. The liver, spleen, and/or lymph nodes may be enlarged.

Stage IV
In addition to lymphocytosis, platelet counts are low (thrombocytopenia), which can increase the risk of bleeding. The liver, spleen, and/or lymph nodes are enlarged. Red blood cell counts may be low or near normal.

Classification of Acute Myeloid Leukemia (AML)

AML Subtypes Instead of Stages

Acute myeloid leukemia is not categorized using a numbered staging system because it affects the bone marrow and blood at diagnosis rather than creating a solid tumor. There are two main systems used to divide acute myeloid leukemia (AML) into subtypes: the World Health Organization (WHO) classification and the International Consensus Classification (ICC). These systems are very similar, although they have a few differences.

Both systems rely on the number of immature blood cells, called blasts, found in the bone marrow or bloodstream. This percentage is an important part of confirming an AML diagnosis. If the leukemia cells have certain genetic or chromosome changes, AML can often be diagnosed when at least 10% of the cells are blasts. If those key genetic changes are not present, the diagnosis usually requires at least 20% blasts.

As research has advanced, AML classification has become more detailed, especially with a better understanding of genetic changes inside leukemia cells.

Disease Status in AML

Acute myeloid leukemia is described by its response to treatments.

Remission
Fewer than 5% leukemia cells in the bone marrow with recovery of blood counts

Minimal Residual Disease (MRD)

Even though the patient is in remission, highly sensitive tests detect small numbers of leukemia cells. MRD+ status indicates a higher likelihood of relapse and the potential need for further treatment.

Refractory AML
Disease that does not respond to treatment

Recurrent AML
The cancer was in remission but has returned, with leukemia cells reappearing in the bone marrow and/or blood.

Phases of Chronic Myeloid Leukemia (CML)

Chronic myeloid leukemia is categorized into three distinct phases rather than traditional stages. These phases reflect how aggressive the disease is and how it is progressing.

Chronic Phase
This is the earliest and most common phase at diagnosis. Patients may have mild or no symptoms, and the disease progresses slowly. Most patients respond well to targeted therapies during this phase.

Accelerated Phase
In this phase, leukemia cells begin to grow more quickly. Blood counts become more abnormal, and symptoms may worsen.

Blast Phase (Blast Crisis)
This is the most advanced phase and behaves similarly to an acute leukemia. There is a high number of immature cells (blasts) in the blood and bone marrow, and symptoms are more severe.

Risk Groups for CMS

In addition to the phase of chronic myeloid leukemia (CML), doctors look at several other factors to better understand how the disease may behave and which treatments are most appropriate. These can include a person’s age, the size of the spleen, platelet levels in the blood, and the number of immature cells (blasts) or other abnormal cells found in the bloodstream.

Based on the assessment, the risk level is categorized into three different groups: low, intermediate, or high, with higher risk groups requiring treatment sooner than low-risk groups.

Access to Advanced Leukemia Care in Southwest Virginia

The Blue Ridge Cancer Care team uses the latest leukemia categorizations and genetic testing to inform important decisions about the timing and types of treatments. If you were diagnosed with leukemia, request an appointment with one of our hematologic oncologists. We are also available to provide second opinions.