Major Differences Between Leukemia and Lymphoma

Leukemias and lymphomas are often grouped together because they are both blood-related cancers. However, there are differences between the two based on where cancer begins and the features that make them separate conditions.

This article explains leukemia and lymphoma symptoms and similarities, as well as their differences. It offers information on how often these cancers occur, who is most at risk, and how improved treatments have changed the outlook for people with some types of blood cancer.

Definitions

Leukemia and lymphoma conditions can seem confusing, in part, because researchers, as well as clinicians who treat people with blood cancers, know much more about the diseases than when they were first identified in the 1800s.

What Is Leukemia?

Leukemia is defined as a progressive, malignant (spreading) cancer that affects the blood-forming organs, of which there are several involved. The cancer changes the growth and development of leukocytes (white blood cells), and the stem cells from which they develop.

Among these organs are:

• Bone marrow. In adults, all red blood cells and most of the granulocytes (a type of white blood cell) are produced in the bone marrow.
• Thymus and spleen. Developed white blood cells migrate to these organs of the lymphatic system. The thymus is in your chest, behind the breastbone. The spleen is in the upper left quadrant of your abdomen.
• Lymph nodes. These nodes are clustered throughout the body to filter the lymphatic fluid.

All of these tissues play a vital role in the development and maturation of the lymphocytes, with some differences between B lymphocytes (B cells) and T lymphocytes (T cells). Special tissues in these organs are important for the maturation of monocytes, a specific type of white blood cell.

What Is Lymphoma?

Lymphoma is a cancer of the lymphoid tissue, which includes both cells and organs. It affects the same organs of the lymphatic system (thymus, bone marrow, lymph nodes, spleen).

But it also can affect other lymphoid tissue organs important to the immune system, including:

• Tonsils
• Parts of the respiratory tract
• Mucous membranes, such as those in the digestive tract

Lymphoma also affects white blood cells, with lymphocytes being the most common cell type found in lymphoid tissue.

Two Key Factors

One key factor in diagnosis involves whether high numbers of white blood cells are circulating in the bloodstream. This excess of white blood cells in the peripheral bloodstream is more typical of leukemia.

Early involvement of the bone marrow also is more typical of leukemia.

Symptoms of Leukemia vs. Lymphoma

Leukemia and lymphoma symptoms will sometimes overlap or may not even be specific to either disease. As a result, these cancers aren't diagnosed on the basis of symptoms alone.

There are, however, characteristic symptoms that may point toward a diagnosis of one disease or the other.

Lymphoma Symptoms

Symptoms of lymphoma vary and may include painless swelling of lymph nodes. These lymph nodes may be visible at sites in your body where lymph nodes are located, including:

• Neck
• Armpits
• Groin

The swelling also may be seen on imaging studies at sites like the mediastinum in your chest, or in retroperitoneal nodes, towards your back behind the abdominal ogans. Other symptoms may include:

• Persistent fatigue
• Fever
• Chills and night sweats
• Unexplained weight loss

Leukemia Symptoms

The most common types of leukemia can produce symptoms such as bone and joint pain. Other symptoms can include:

• Fatigue and general weakness
• Pale skin due to low levels of red blood cells, known as anemia
• Easy bleeding or bruising due to low levels of platelets, or thrombocytopenia
• Fever
• Weight loss
• Swollen lymph nodes of the spleen and liver

People with lymphomas may have symptoms referred to as B symptoms, which often indicate a more aggressive or faster-growing cancer.

B symptoms of lymphoma include fevers, unintentional weight loss, and drenching night sweats.

Types of Lymphoma and Leukemia

Leukemia and lymphoma cancers arise from different types of cells. Understanding the origin of these cancers can be made easier by describing a few specific types of these diseases.

Types of Leukemia

There are four basic types of leukemia.Two of these types are described as myeloid, meaning they are related to the bone marrow where the body produces white blood cells.

These myeloid leukemias are called:

• Acute myeloid leukemia (AML)
• Chronic myeloid leukemia (CML)

The word myeloid also refers to a group of cells that differentiate, or mature from, a common myeloid progenitor cell type. The myeloid term also includes these blood-forming tissues.

The two remaining lymphocytic leukemia types are called:

• Acute lymphocytic leukemia (ALL)
• Chronic lymphocytic leukemia (CLL)

These lymphocytic leukemias arise from cells that are part of lymphoid tissues but are technically not lymphomas. That's because they start out in the bone marrow and later migrate, or move, to the lymphoid tissue.

Types of Lymphoma

Lymphomas are diagnosed as one of two basic types. These types of lymphoma are Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL).

Some blood cancers have features that are characteristic of both leukemia and lymphoma. But generally, the lymphoma cells do not appear in the blood circulating in your body. Though they also arise from white blood cells or their precursors, they aren't defined as leukemias.

Differences in Incidence

There are differences between leukemias and lymphomas in their incidence or how often they occur. Overall, more people in the United States develop lymphomas than leukemias.

The American Cancer Society expects that roughly 89,010 people will be diagnosed with lymphoma in 2022: 80,470 with NHL and 8,540 with HL.

In 2022, 60,650 people are expected to be diagnosed with leukemia. This is broken down by leukemia type:

• 20,050 new cases of AML
• 8,860 new cases of CML
• 6,660 new cases of ALL
• 20,160 new cases of CLL

Differences in Age at Diagnosis

Though leukemia is the most common childhood cancer, accounting for about 28% of all cancers in children, it is most frequently diagnosed among adults aged 65 to 74.

By comparison, lymphomas make up only 10% of childhood cancers. Many lymphomas are more common in people over the age of 55.

There is overlap, however. Some chronic leukemias are much more common in older people, whereas HL has its first peak in incidence between the ages of 15 and 40.

Treatment and Outlook

With respect to leukemia and lymphoma treatment, there is a significant difference between blood-related cancers and the breast, lung, and other cancers that arise from solid tumors.

The targeted therapy Gleevec (imatinib), for example, has changed CML from being an almost universally fatal disease to a condition often managed as a chronic disease. ALL was at one time usually rapidly fatal, yet around 90% of children with this disease can now be cured.

Life expectancy with Hodgkin lymphoma has improved dramatically as well. This disease, which had a 5-year survival rate of just 10% for people living with the diagnosis a century ago, now has a 5-year survival rate of over 90% in early stage and well over 50% for stage 4 disease.

In contrast, many stage 4 solid tumors, such as breast cancer, lung cancer, and pancreatic cancer, are not curable and are almost always fatal over time. That said, some approaches to treatment, such as targeted therapies and ​immunotherapy offer hope that those with solid tumors will eventually experience the advances in treatment that many with blood-related cancers now realize.

Summary

Both leukemias and lymphomas are considered "blood-related" cancers. They involve cells that play an important role in immune function. There are general differences between the two cancer types but there also are similarities in the pathways in the body from which they arise.

Leukemias are cancers that affect organs involved in producing blood, including the bone marrow, spleen, and thymus. They affect white blood cells that grow and migrate to these organs in the body. Lymphomas affect cells and tissue of the same organs, but also others including the tonsils.

Lymphoma and leukemia symptoms can be similar though lymphomas occur more often. It's important to get an accurate diagnosis, so see your healthcare provider about your symptoms.

A Word From Verywell

Advances in treatment options for leukemia and lymphoma mean that blood cancers one thought fatal, such as ALL in children, are now survived in a majority of cases. The diagnosis for you or your child may seem overwhelming but your healthcare team can help you to better understand the outlook and help to connect you with support resources.