chronic leukemia
Meaning of chronic leukemia: Slow growing blood cancers whose cells mature far enough to function, which is why they are so often found by accident.
Definition of chronic leukemia
Chronic leukemia is a cancer of blood forming cells that develops slowly, over months or years. The abnormal cells mature far enough to look almost normal and to do part of their job, so they accumulate gradually rather than shutting the marrow down. Many people have no symptoms at diagnosis, and the disease is picked up on a routine blood count.
How does it differ from acute leukemia?
| Chronic | Acute | |
|---|---|---|
| Cells involved | Partly matured, able to do some of their work | Very immature blasts that cannot function |
| Speed | Months to years | Days to weeks |
| How it is found | Often on a routine blood count in a well person | Usually because the person has become ill |
| Urgency | Treatment may be deferred and the disease watched | Treatment usually starts quickly |
The words chronic and acute here describe the biology of the cells, not simply how long someone has been unwell.
What are the main types?
Chronic lymphocytic leukemia arises from mature B lymphocytes and is the commonest leukemia in adults in Western countries. Chronic myeloid leukemia arises from the myeloid line and is defined by a specific swap of material between two chromosomes, creating a fused gene that drives continuous growth. Rarer forms include chronic myelomonocytic leukemia and hairy cell leukemia. The type is established from surface markers and gene changes rather than from the blood count alone.
What does it do to the body?
The abnormal cells crowd the bone marrow and take up space needed for normal production, so anemia, low platelets and infections appear as the disease advances. Enlarged lymph nodes and an enlarged spleen are common, because the surplus cells collect there. Tiredness, night sweats, weight loss and a feeling of fullness after small meals are the usual complaints. Immunity is weakened even while the white cell count is high, since the abnormal cells work poorly.
Can a chronic leukemia change?
Yes, and that possibility defines how it is followed. Chronic myeloid leukemia can transform into a fast moving illness resembling acute leukemia, a change called blastic phase and usually preceded by an accelerated phase. Chronic lymphocytic leukemia can transform into an aggressive lymphoma. Targeted drugs that block the fused gene have altered the course of chronic myeloid leukemia substantially, so transformation is seen far less often than it once was.
Used in a sentence
The routine blood count showed a marked lymphocytosis, and further testing confirmed chronic leukemia.
Good to know
Chronic and acute describe how mature the abnormal cells are rather than how long a person has been ill, and a chronic leukemia can transform into a fast moving disease resembling acute leukemia.
Word origin
Where “chronic leukemia” comes from
Leukemia comes from the Greek leukos, meaning white, and haima, meaning blood, and chronic from chronos, meaning time.