Lymphoma - A Cancer of Lymphocyte White Blood Cells

Doctor checking patient's lymph nodes
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Lymphoma is a kind of blood cancer, or hematologic malignancy. Blood consists of the liquid, called plasma, and all of the blood cells -- the red blood cells, white blood cells (WBCs), and platelets that float around in the plasma. Cancers that develops in these cells are often called hematologic malignancies.

A Cancer of the WBCs

All types of white blood cells (and red) are made in the bone marrow – the soft, spongy inner parts of certain bones such as the hipbone and thighbone.

Leukemia and lymphoma are cancers that arise in the white blood cells. In lymphoma, the cancer occurs in the family of white blood cells known as lymphocytes. In lymphoma, cells that are members of this lymphocyte white blood cell family start multiplying and growing without the normal checks and balances, in a less controlled manner, to form a cancer.

Lymphocytes and Lymph Nodes

Lymphoma differs from leukemia in that most cases of lymphoma begin in the lymph nodes – those bean-shaped bumps or nodules beneath the skin and throughout the body that help filter the lymph and fight infection. The lymph nodes are small structures that are often present along blood vessels. As the cancer cells grow and multiply, the lymph nodes enlarge and form lumps.

Symptoms

The most common symptoms of lymphoma include painless lumps in the neck, armpits or groin. Several other warning signs and symptoms of lymphoma include fever, weight loss and sweating at night.

Lymphoma can also affect other organs of the body besides lymph nodes and give rise to a variety of additional symptoms that prompt an individual to see a doctor.

Classification

Lymphoma is not a single cancer. There are two main groups -- Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). There are many different types of both HL and NHL.

In total, there are more than 30 different types of lymphoma, some common and some rare. Some lymphomas are very different from others.

Not much is known about the cause of lymphoma. Germs have been linked to the development of cases of both HL and NHL. Parasites like malaria, viruses like the one that causes mono, and bacteria such as the one associated with stomach ulcers have all been implicated in the development of lymphoma. However, in most cases, these infections are links, but not sufficient in and of themselves to cause lymphoma. Though some viral infections are known to cause this cancer, in most individuals, the reason for getting a lymphoma is unclear. Read about the

Once an individual is diagnosed with lymphoma, several tests are performed to identify the type of lymphoma and finding the stage of lymphoma. A treatment plan for the lymphoma is then decided. Available treatments can cure many patients of this cancer and can control the disease in many others.

Biopsy and Evaluation

To test for lymphoma, doctors typically perform a biopsy, taking a small sample of tissue from the affected nodes or organs. The samples are then viewed under a microscope by a pathologist and undergo special tests in the laboratory.

PET-CT

Something called PET-CT is becoming increasingly important in evaluating many different types of lymphoma. PET stands for positron emission tomography. There are different forms of PET, one of which uses a radioactive form of sugar, or FDG, which is taken up, in general, by HL and various NHL cells quite well, or with high avidity. Not all lymphomas can be imaged using FDG-PET because not all lymphomas take up the radioactive sugar well. Likewise, non-cancerous structures may light up on the PET scan, potentially increasing the risk for false positives.

PET scanning is often combined with CT scanning, and PET scanning is generally more sensitive than CT alone in detecting certain types of lymphoma.

The form of radiation used in PET is similar to that of x-rays, however, combined exposure from a PET-CT is about 10-20 times higher than exposure from a regular x-ray. PET/CT, then, can have remarkable benefits in terms of detection and disease evaluation, but also carries risks in that a substantial radiation dose is delivered in the process. Thus, the risk-benefit ratio should be carefully weighed for each individual prior to every study.

Treatment and Prognosis

Because lymphoma is such a diverse collection of different malignancies, it doesn’t make sense to talk about specific treatments and survival times for all lymphoma patients. You can, however, get a better sense of these things with additional information about specific lymphoma type as well as pertinent information about the individual patient who has that specific lymphoma type.

In general, treatments for lymphoma often involve chemotherapy and/or radiation therapy. There are also targeted therapies and immune-based therapies, often used in concert with more conventional therapeutic regimens.

Sources:

Cheson BD, Fisher RI, Barrington SF, Cavalli F, Schwartz LH, Lister TA.

Recommendations for initial evaluation, staging, and response assessment of Hodgkin and non-Hodgkin lymphoma: the Lugano classification. J Clin Oncol. 2014;32(27):3059-3068.

American Cancer Society. How is non-Hodgkin lymphoma staged? http://www.cancer.org/cancer/non-hodgkinlymphoma/detailedguide/non-hodgkin-lymphoma-staging Accessed January 2015.

Smith, Monica. New Lymphoma Recommendations Reflect Advances. http://www.clinicaloncology.com Accessed July 2016.

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