Home » Pet Health » Cancer 101 » Difference Between a Solid Tumor and Blood Cancer


Cancer is a disease characterized by the uncontrolled division of abnormal cells due to changes in the genetic machinery within the cell. These genetic alterations can affect the functions of normal cells and tissues. Cancer specialists divide cancer into two main types: solid tumor cancers and blood cancers.

Solid tumors are abnormal ‘solid’ masses of cells that grow in organ systems anywhere in the body (except for the blood). They are usually lacking fluids or cysts. Some examples of solid tumors may include cancers of the lung, breast, prostate, colon, rectum, and bladder.

On the other hand, blood cancers or hematological cancers affect the production and function of blood cells. Blood cancer generally originates in the bone marrow, which is the spongy tissue inside bones where new blood cells like red blood cells, white blood cells, or platelets are formed. Blood cancer is characterized by the uncontrolled growth of abnormal blood cells that interrupt the functions of normal blood cells such as fighting off infections or preventing bleeding. The three main types of blood cancer are:

    1. Leukemia: This type of cancer is caused by the uncontrolled and rapid production of abnormal white blood cells that are unable to fight infection. These cells also impair the ability of the bone marrow to produce other blood cells.
    1. Lymphoma: This type of blood cancer affects the lymphatic system, which is involved in the production of lymphocytes (a type of white blood cell that fights infection). The formation of abnormal lymphocytes (known as lymphomas) impairs the immune system.
    1. Myeloma: This cancer forms in a type of white blood cell called a plasma cell. Plasma cells are white blood cells that produce antibodies to fight infections. Myeloma cells disrupt the normal production of antibodies, thus affecting the immune system and enhancing susceptibility to infections. The myeloma cells also affect the normal production of red and white blood cells in the bone marrow.

Solid tumors and blood cancers are treated differently. Treatment of solid tumors may include a combination of several types of therapy, such as chemotherapy, radiation therapy, and surgery, while treatment for blood cancers depends on the type of blood cancer, the rate at which the cancer is progressing, and whether the cancer has spread to other parts of the body. Common treatments include chemotherapy, radiation therapy, bone marrow transplantation, immunotherapy (using the immune system to fight the cancer), or targeted therapy (therapy that targets the proteins that control the cancer cells).

Learning about the different types of cancer can help you appreciate how your pet is affected if they receive a cancer diagnosis. You will understand what to expect, and your knowledge will give you the confidence to discuss appropriate treatments for your beloved furry friend. So, if your pet is diagnosed with cancer, talk to your vet about the next steps to ensure you and your pet have many happy days after diagnosis.

The Pet Cancer Foundation’s Website Editorial team is comprised of veterinarians, veterinary oncologists, and veterinary technicians, as well as scientific writers and editors who have attained their PhD’s in the life sciences, along with general editors and research assistants. All content found in this section goes through an extensive process with multiple review stages, to ensure this extended resource provides pet families with the most up-to-date information publicly available.

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Last Updated: May 1, 2022

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The following sources were referenced to write the content on this page: 

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The Pet Cancer Foundation’s medical resource for pet owners is protected by copyright.

For reprint requests, please see our Content Usage Policy.