Childhood Leukemia: Long-Term Prognosis and Survival Rates
When discussing long-term survival rates for childhood leukemia and other types of childhood cancer, oncologists rarely use the term “cure”. Instead, to discuss short-term outlook and response to treatment, doctors will discussion remission, minimal residual disease, and relapse. For longer term outlook, physicians use a number called the 5-year survival rate. Thanks to advances in treatment options, both remission rates and 5-year survival rates for childhood leukemia have significantly improved over the past several decades, and children who remain free of leukemia after five years are generally considered “cured”.
In the short term, the goal of chemotherapy is to achieve remission. Remission is defined by a lack of leukemia cells after the initial induction phase of chemotherapy. A child is considered to have achieved remission if the bone marrow contains less than 5% of blast cells, blood cell counts are within normal limits, and the child shows no symptoms of disease. Further chemotherapy after remission is designed to destroy any remaining leukemia cells, as well as prevent the growth of new cancer cells.
If the leukemia does not respond to initial treatment, it is classified in one of two ways. Minimal residual disease means that cancer cells in the bone marrow can be detected with more sensitive tests than a standard microscope scan. MRD usually involves a higher risk of relapse (growth of new cancer cells). Active disease means that cancer cells are still easily detectable in the bone marrow, indicating either that the leukemia has not responded to treatment or that there has been a relapse of the disease. In both of these cases, oncologists will likely pursue more intensive chemotherapy in order to achieve remission.
The 5-year survival rates for both Acute lymphocytic leukemia (ALL) and Acute myelogenous leukemia (AML) have greatly improved over the past few decades. For ALL, the 5-year survival rate is now more than 85%. For AML, the 5-year survival rate is 60-70%; however, these rates vary greatly depending upon the subtype of AML as well as other factors.
Prognosis Factors for Childhood Leukemia
When discussing 5-year survival rates for childhood leukemia (as with any form of childhood cancer), it is important to remember that the specific numbers given above are only an average compiled from all treated cases of childhood leukemia across the Unites States, and do not provide a specific prognosis for your child. Your child’s oncology team will help you understand your child’s prognosis and potential for long-term survival, based on your child’s unique diagnosis, response to treatment, and general health.
There are several key prognosis factors that will help your child’s oncology team understand the degree of risk presented by your child’s leukemia, as well as the intensity of the requirement treatment.
Prognosis factors relative to ALL: During the diagnostic process, childhood leukemia is generally categorized into three “risk groups”: standard-risk, high-risk, or very high-risk. These risk groups will help determine the intensity of the required treatment and may impact the child’s long-term prognosis. Generally speaking, children in the standard-risk group have a better outlook than children in the very high-risk grouping; however, thanks to advances in treatment options, even children with very high-risk leukemia still have an excellence chance of achieving remission and long-term cure. Other prognosis factors include:
- Age at diagnosis: Children between the ages of 1 and 9 tend to have a more positive prognosis than children under the age of 1 or over the age of 10. This applies only to B-cell ALL; age does not seem to be a prognosis factor in T-cell ALL.
- Initial white blood cell count: Children with very high WBC counts at diagnosis are generally placed in the high or very high risk group and will require more intensive treatment.
- Subtype of ALL: Children who are diagnosed with pre-B, common, or early pre-B-cell ALL have a more positive prognosis outlook than children with mature B-cell leukemia; this is also true of B-cell ALL with intensive treatment.
- Gender: Girls have a slighter better prognosis outlook than boys, although this gap has shrunk in recent years than to more advanced treatment options.
- Race/ethnicity: African-American and Hispanic children seem to have a slighter worse outlook than other ethnicities.
- Spread to other organs: The spread of the leukemia into specific organs such as the fluid around the brain and spinal cord, as well as the testicles in boys, usually classifies the leukemia as high or very high risk with a less favorable outlook.
- Number of chromosomes and chromosome translocations: Studies have linked some prognosis factors to the number of chromosomes within the leukemia cells, as well as translocations (or the swapping of genetic material) between specific chromosomes.
- Response to treatment: The initial reduction of cancer cells in the bone marrow during the first 1 to 2 weeks of chemotherapy helps determine long-term outlook; however, if the leukemia does not respond as expected in this time frame, doctors will generally initiate a more intensive treatment protocol.
Prognosis factors for AML: The prognosis factors for AML are similar to those listed above for ALL but with some minor differences; however, prognosis factors in general do not seem to be quite as important in either guiding treatment or predicting short- or long-term outcomes.
About American Childhood Cancer Organization
American Childhood Cancer Organization (ACCO) is a non-profit charity dedicated to helping kids with cancer and their families navigate the difficult journey from cancer diagnosis through survivorship. Internationally, ACCO is the sole U.S. member of Childhood Cancer International (CCI), the largest patient-support organization for childhood cancer in the world. Here in the United States, ACCO promotes the critical importance of ensuring continued funding into new and better treatment protocols for childhood cancer. And most importantly, ACCO is focused on the children: developing and providing educational tools for children fighting cancer and their families, empowering them in their understanding of childhood cancer and the medical decisions they must make during this difficult journey. All of ACCO’s resources are available free of charge for families coping with childhood cancer.