Leukemia: The Facts We Need to Know

Leukemia is a type of cancer that starts in the bone marrow when large volumes of abnormal, unhealthy blood-forming cells develop. When they’re healthy, these cells have specialized roles in the body. When they’re unhealthy, the cells can’t perform their roles. Leukemia develops when these unhealthy, immature cells crowd the remaining normal cells and prevent the normal cells from performing their roles. Here’s what you need to know about the disease:


Types of Leukemia

There are many types of leukemia, and all but four of them are very rare. We’ll focus on the four most common types:

Chronic Lymphocytic Leukemia (CLL)

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults and accounts for about 25% of diagnoses. It affects older people almost exclusively and is very rare in children, but anyone can have CLL.

CLL develops from undeveloped lymphocytes, which are a type of white blood cell. The abnormal cells form in the bone marrow and spread to the blood.

Acute Myeloid Leukemia (AML)

Acute myeloid leukemia (AML) is the second most common type of leukemia in adults. That said, it’s a rare type of cancer overall, accounting for about 1% of cancer diagnoses. AML affects older people most often, but it can develop at any age.

AML develops in the bone marrow but spreads quickly to the blood. It usually develops from immature, undeveloped white blood cells (other than lymphocytes).

Chronic Myeloid Leukemia (CML)

Chronic myeloid leukemia (CML) accounts for about 10% of leukemia diagnoses (15% in adults).

CML develops when a genetic-level change happens in immature myeloid cells. Healthy myeloids create platelets, red blood cells, and most white blood cells (aside from lymphocytes).

Acute Lymphocytic Leukemia (ALL)

Acute lymphocytic leukemia (ALL) is the least common type of leukemia in adults, but it’s the most common type in children. Most children who are diagnosed with ALL are younger than five years.

ALL develops when there are too many immature lymphocytes, and they don’t develop properly. The abnormal lymphocytes overtake normal lymphocytes and prevent them from functioning properly (fighting infection).

Risk Factors for Leukemia

Anyone can get leukemia, but there are some factors that increase the risk:

  • Smoking - research shows that people who smoke are 40% more likely to get AML (the number drops to 25% for former smokers)
  • Exposure to cancer-causing agents, like radiation and benzene
  • Previous radiation therapy or chemotherapy
  • Certain genetic syndromes, including Down syndrome
  • Family history - people with a first-degree relative who has CLL faces a two-to-four times higher risk of developing the same type

Signs & Symptoms

It’s worth noting that early leukemia doesn’t usually cause symptoms. All the symptoms associated with the disease are also characteristic of other, less severe blood-related conditions, including mononucleosis (the kissing disease). If you have any of the following symptoms, you should see your doctor right away - it’s usually better to err on the side of caution. If nothing else, you’ll gain peace of mind.

  • Unusually easy bleeding or bruising
  • Swollen lymph nodes
  • Nose bleeds
  • Loss of appetite and unintentional weight loss
  • Fatigue, fever, and chills (flu-like symptoms)
  • Night sweats
  • Achy bones
  • A small red, bumpy rash
  • Severe and persistent infections


A blood test that shows an abnormal count of white blood cells may suggest leukemia (among many other conditions). To confirm the diagnosis, the doctor will take a biopsy (small sample) of bone marrow from the pelvic bone. Technicians at a lab will assess the biopsy for abnormalities.


Acute leukemias (including ALL and AML) are treated differently than chronic (like CLL and CML).


In acute leukemia, the goal of treatment is to initiate remission. The primary treatment is chemotherapy. Because people with acute leukemia have low counts of healthy blood cells, the chemotherapy treatment is supplemented with platelet transfusions to control bleeding. Medications are used to control symptoms, side-effects, and infection risk.

Patients with ALL can expect routine treatments for up to two years before they achieve remission. Patients with AML may need a stem cell transplant to help them produce healthy blood with healthy cells.


CLL usually presents in older people, and it develops quite slowly. Not all patients need treatment, but if symptoms are affecting a person’s quality of life, treatment to relieve the symptoms is recommended.

Patients with CML can manage their symptoms for years with oral chemotherapy drugs. However, CML often progresses to an acute form, so doctors usually recommend a bone marrow transplant before that happens. A drug called imatinib can help patients with CML achieve remission. The drug works by targeting the genetic-level change that leads to blood cell abnormalities.


The outlook for patients with leukemia depends largely on the type.

The 5-year survival rate for the disease overall is about 61%.

If you’ve been diagnosed with leukemia and you feel that you’d benefit from support, the Leukemia and Lymphoma Society can help.


*All information acquired from the American Cancer Society and the Children’s Hospital of Philadelphia.