Leukemia is an umbrella term for cancers of the blood and bone marrow.
The bone marrow is the soft inner part of bones where new blood stem cells are created. In a normal blood cell process, the stem cells slowly mature into red blood cells, white blood cells, and platelets, before circulating throughout the body.
In someone with leukemia, however, abnormal cancer cells affect this blood cells production. The cancer cells do not function like healthy blood cells, thus depriving the individual of healthy blood function. Like all cancer cells, they grow and divide rapidly, crowding out the healthy cells in the bone marrow and potentially spreading to other parts of the body.
The Difference Between Acute and Chronic Leukemia
Blood cancers, such as leukemia, are very complex. Leukemia has several subtypes which depend on the type of blood cell affected (myeloid or lymphoid) and the rate at which the cancer progresses. This rate of progression is what classifies the cancer as acute or chronic.
Acute leukemia means the affected stem cells cannot mature at all, and the leukemia progresses quickly. “With acute leukemia, the cells are multiplying very quickly, and the majority of the patient will become symptomatic very early,” says Michal Bar-Natan Zommer, MD, assistant professor of hematology and oncology at Mount Sinai Hospital.
Those with acute forms of leukemia tend to have more severe symptoms than those with chronic forms of leukemia. These symptoms may be vague or non-specific, and differ depending on the type of leukemia you have, such as acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL).
“For the acute leukemia you have to get treatment immediately because otherwise the disease will progress very quickly and give you more symptoms,” says Dr. Zommer.
Chronic leukemia means the stem cells are able to develop partially, but do not function as effectively as healthy mature blood cells. As a result, chronic leukemia tends to be less severe and spread more slowly than acute leukemias.
“With the chronic phase the cells usually grow very slowly and accumulate over time, and therefore the patients have no symptoms for a long period of time,” says Dr. Zommer.
Although many patients may not have symptoms initially, symptoms can develop—especially if the cancer spreads. For instance, in chronic lymphocytic leukemia, “the cells growing in the [bone marrow and blood] eventually will grow in the lymph nodes, in the spleen, or in the liver,” says Dr. Zommer.
As the cancer spreads, the patient may start to feel lumps in their neck or elsewhere in their body. “They can be tired because they have anemia, [or] they can have recurrent infection because their ability to fight infection is a little bit less,” says Dr. Zommer.
Treatment for blood cancers such as leukemia vary depending on the type and subtype the patients has. “If [a patient] is feeling unwell, you should definitely go an seek advice and go to a physician,” says Dr. Zommer.
“Today the prognosis is better than it was before,” says Dr. Zommer. Lots of ongoing research is providing new ideas, insights, and potential solutions. “Fighting the cancer [has] become easier [and] more successful with time.”