What Are Blood Cancers?

Blood cancers, also called hematologic cancers, occur when blood cells grow abnormally, interfering with how normal blood cells function. Types of blood cancer vary based on the cells they affect as well as their incidence, method of diagnosis, and their prognosis. There are three main types of blood cancer:

• Leukemia: Cancer in the white blood cells
• Lymphoma: Cancer in the lymphatic system
• Myeloma: Cancer in the plasma cells

Leukemia

Leukemia is the most common cancer for people who are more than 55 years old and children who are younger than 15 years old. It occurs in the bone marrow when abnormal white blood cells are created too quickly and destroy normal blood cells.

Types

Acute leukemia occurs quickly and can become severe in only a short time, while chronic leukemia is slow-growing and will advance slowly.

There are four common types of leukemia. Types are determined based on how quickly the disease progresses, and which white blood cells are impacted.

AML

Acute myeloid leukemia (AML) is the most common form of leukemia in adults. It is fast-growing and impacts the blood and bone marrow. Treatment options include chemotherapy, radiation therapy, targeted therapy, or stem cell transplants.

ALL

Acute lymphocytic (lymphoblastic) leukemia (ALL) progresses rapidly and can affect the blood marrow throughout the body. It can spread to the liver, spleen, or lymph nodes. It is most common in children under 15 years old or adults over 45 years old. ALL accounts for the largest diagnosis of leukemia in children under 15 years old, but it is rare in adults.

CLL

Chronic lymphocytic leukemia (CLL) usually impacts older adults and accounts for a third of all leukemia diagnoses; its incidence being very close to that of AML. Some forms of CLL begin slowly and symptoms may not be obvious for years, while other forms of CLL grow quickly. 

HCL

Hairy cell leukemia (HCL) is a rare form of CLL. It progresses slowly and most commonly occurs in middle-aged people or older people. HCL is a chronic disease.

CML

Just 10% of leukemias are chronic myeloid leukemia (CML). It is more common in adults than in children and can change from a slow progression to rapid growth. Unlike other forms of leukemia, CML has been associated with an abnormal chromosome known as the Philadelphia chromosome (Ph chromosome). Eventually it can spread to other parts of the body.

Risk factors

Risk factors for leukemia include:

• Smoking
• Family history
• Genetic syndromes like Down syndrome
• Exposure to high doses of radiation
• History of chemotherapy or radiation therapy 

Prognosis

Although there is no cure for leukemia, survival rates for leukemia have improved in recent years. Between 2010 and 2016 the five-year survival rate was 63.7%.

Lymphoma

Lymphoma is the result of abnormal white cells called lymphocytes multiplying rapidly and overwhelming the lymphatic system.

Types

There are two main forms of lymphoma:

• Hodgkin: Typically affects those between the ages of 15 and 35 and accounts for less than 10% of lymphoma cases and is slow growing.
• Non-Hodgkin: Typically affects those more than 60 years old and occurs in B cells. It is normally fast growing.

Risk Factors

Those aged between 15 to 35 or over 55 are at increased risk for Hodgkin lymphoma, while those aged over 60 are at risk for non-Hodgkin lymphoma.

Those with a weakened immune system are at risk for lymphoma, as are those who have had viruses like HIV or Epstein-Barr.

Prognosis

The five-year survival rate for Hodgkin lymphoma is 87%. The five-year survival rate for non-Hodgkin’s lymphoma is 73%.

Multiple Myeloma

Multiple myeloma is a cancer that begins in the plasma cells. Plasma cells help the immune system by making antibodies to attack germs. Symptoms are typically not seen until the cancer has advanced and spread throughout the body.

Types

Monoclonal gammopathy of undetermined significance (MGUS) is a benign condition that puts patients at an increased risk for cancer. On average, every year, 1% of people with MGUS go on to develop multiple myeloma.

Smoldering myeloma is a precancerous condition where half of those diagnosed will progress to multiple myeloma within five years.

Risk Factors

Men are more more likely to be diagnosed with multiple myeloma than women. African-Americans are twice as likely to be diagnosed with multiple myeloma than Caucasians.

Prognosis

Although multiple myeloma is treatable, it is rarely curable. The five-year survival rate for myeloma is 52%.

Myelodysplastic Syndrome (MDS)

In myelodysplastic syndrome (MDS), abnormal blood cells in the bone marrow struggle to make new blood cells. This can impact different types of cells, but most commonly results in a shortage of red blood cells. There are different kinds of MDS that are categorized based on blood cells affected. In one in three patients, MDS can progress to acute myeloid leukemia (AML). In the past, the condition has been referred to as preleukemia.

Types

There are three different types of MDS:

• Refractory anemia occurs when there aren't enough red blood cells.
• Refractory cytopenia with multilineage dysplasia occurs when there aren’t enough of at least two kinds of blood cells. This may progress to AML.
• Unclassified MDS occurs when there is a shortage of one type of blood cell. 

Risk factors

Risk factors include:

• People aged over 60 are at higher risk
• Men are more likely to be diagnosed with MDS than women
• Smoking increases risk
• Chemotherapy for other forms of cancer can increase risk, and risk increases if chemo and radiation therapy are combined
• Some genetic diseases
• Exposure to radiation or benzene

Prognosis

A stem cell transplant is the only potential cure for MDS. Survival rates vary based on type of MDS, progression to AML, and other risk factors. The average survival rate for lower-risk patients who do not receive a bone marrow transplant is five years, while the five-year survival for high-risk patients is five months.

Myeloproliferative Disorder (MPD)

Myeloproliferative disorder (MPD), also referred to as myeloproliferative neoplasm, causes the abnormal growth of blood cells in the bone marrow. It can affect platelets, white blood cells, and red blood cells.

Types

Types of MPD include:

• Chronic eosinophilic leukemia (CEL): Occurs when the bone marrow makes too much of a kind of white cell called eosinophils.
• Chronic neutrophilic leukemia (CNL): Causes an oversupply of certain kinds of white blood cells.
• Chronic myelogenous leukemia (CML): Causes the growth of abnormal types of white blood cells.
• Essential thrombocythemia: Causes the overproduction of platelets which can lead to clogged blood vessels, heart attack, and stroke.
• Polycythemia vera: Occurs when too many red blood cells are produced by the marrow. This is associated with a genetic mutation.
• Primary myelofibrosis: Occurs when the bone marrow produces too much collagen.

Risk Factors

Risk factors vary based on type of MPD. Age, gender, and exposure to high levels of radiation, chemicals, or wiring may increase risk.

Prognosis

Survival rates are highly variable and depend on type of MPD, overall health, and response to treatment. Prognosis is generally good with appropriate treatment. The leukemic transformation in MPD differs with the type of MPD. The risk at 10 years may be as high as 20% in myelofibrosis.

A Word From Verywell

Survival rates from blood cancer have improved in recent years, thanks to newer treatments. As there are not currently any effective screening options for early detection of blood cancer, if you experience any unusual symptoms like fever and chills, coughing, chest pain, loss of appetite, night sweats, or other unusual symptoms, speak with your healthcare provider, especially if you have any risk factors.