General Information About Leukemia

Leukemia is a form of cancer that affects bone marrow and the production of white blood cells. The disease exists in several forms, but is always malignant. Over 30,800 cases are diagnosed in the United States every year. Although the disease is most common in people over the age of sixty, acute leukemia is the most common malignancy in children.

Blood cells are categorized into three different types: red blood cells (RBCs), white blood cells (WBCs), and platelets. RBCs carry oxygen throughout the body. WBCs protect against infection, and platelets control blood clotting. All three types are formed through a process known as hematopoiesis.

Hematopoiesis begins in the bone marrow. Yellow bone marrow is composed mostly of fat cells. Red bone marrow produces stem cells—unspecialized cells that can develop into any of the three types of blood cell. A child has more red marrow than an adult.

Leukemia develops from hematopoiesis abnormalities. Stem cells fail to develop and mature appropriately, leading to excessive numbers of myeloid and lymphoid cells (two different types of WBCs). Over time, these abnormal cells crowd out healthy cells, causing a variety of debilitating symptoms.

A number of symptoms are associated with this cancer. The three most common are anemia, heightened infection susceptibility and severe bleeding. All are connected directly to imbalances in blood count.

The low RBC levels attributable to the disease often cause anemia. Anemia is characterized by fatigue and pale skin.

Healthy WBCs are responsible for fighting infection, and are important elements in the body's immune system. Low levels result in frequent infections. Relatively harmless diseases can become serious when the immune system is compromised.

Platelets control the blood's ability to clot. Low levels of platelets lead to easy bruising and severe bleeding from cuts. Small cuts take longer to heal.
Statistics and Survival Rates

With over 30,800 new cases a year in the United States, leukemia is a very common form of cancer. Over 165,000 Americans live with the disease, and it claims approximately 4,500 lives a year in the US.

Despite these numbers, survival rates are promising. In the 1960s the five-year survival rate from the time of diagnosis was only fourteen percent. Since then, survival rates have climbed steadily, to an overall five-year survival rate of 46 percent.

The body has three basic types of blood cells: red blood cells, platelets and white blood cells. This breakdown is designed to help you make sense of WBCs and RBCs and their various classifications:

 

Red blood cells (erythrocytes) transport oxygen from the lungs to the body's tissues.

 

Platelets play an important role in clotting.

 

White blood cells (leukocytes) act as the body's defense system. White blood cells can be further divided into granulocytes, monocytes/macrophages and lymphocytes. Granulocytes are the emergency response system: neutrophils respond to bacterial infection; eosinophils respond to parasitic infection and allergens; basophils respond to allergens and contain histamines. Monocytes/macrophages remove dead tissue and respond to bacterial and fungal infections. Lymphocytes are divided into B cells and T cells. B cells produce specific antibodies in response to infection. T cells are either cytotoxic T cells that destroy infected cells, or helper T cells that regulate the immune system response.