It is a type of cancer that affects cells of the immune system, called lymphocytes.
Just as cancer represents many different diseases, lymphoma represents various lymphocyte cancers, with 35 to 60 different subtypes.
A lymphoma is a group of cancers that affects cells that play a role in the immune system and mainly represents the cells involved in the body’s lymphatic system.
The lymphatic system is part of the immune system. It consists of a network of vessels that carry a fluid called lymph, similar to how the network of blood vessels has blood throughout the body.
Lymph contains white blood cells called lymphocytes present in the blood and tissues.
Lymphocytes attack a variety of infectious agents and many cells in the precancerous stages of development.
Lymph nodes are small collections of lymphatic tissue that occur throughout the body. The lymphatic system involves channels that connect thousands of lymph nodes scattered throughout the body.
Lymph flows through the lymph nodes and other lymphatic tissues, such as the spleen, tonsils, bone marrow, and the thymus gland.
These lymph nodes filter lymph, carrying bacteria, viruses, or other microbes.
At sites of infection, large numbers of these microbial organisms accumulate in regional lymph nodes and produce the local swelling and tenderness typical of a localized infection.
These enlarged and occasionally confluent collections of lymph nodes (so-called lymphadenopathy) are often called “swollen glands.”
In somebody areas (such as the front of the neck), they are often visible when swollen. Lymphocytes recognize infectious organisms and abnormal cells and destroy them.
There are two main subtypes of lymphocytes: B lymphocytes and T lymphocytes, also known as B cells and T cells.
B lymphocytes make antibodies (proteins that circulate through the blood and lymph and adhere to infectious organisms and abnormal cells).
Antibodies essentially alert other immune system cells to recognize and destroy these intruders (also known as pathogens).
The process is known as humoral immunity. T cells, when activated, can kill pathogens directly.
T cells also play a role in the control mechanisms of the immune system to prevent the system from becoming overactive or underactive.
After fighting an invader, some of the B and T lymphocytes “remember” the invader and are prepared to fight it if it returns.
Cancer occurs when normal cells undergo a transformation by which they grow and multiply uncontrollably. Lymphoma is a malignant transformation of B or T cells or their subtypes.
As abnormal cells multiply, they can collect in one or more lymph nodes or other lymphatic tissues such as the spleen.
As cells multiply, they form a mass often called a tumor.
Tumors often overwhelm surrounding tissues by invading their space, depriving them of oxygen and nutrients necessary to survive and function normally.
In lymphoma, abnormal lymphocytes travel from one lymph node to another, sometimes to remote organs, through the lymphatic system.
While lymphomas are often limited to the lymph nodes and other lymphatic tissues, they can spread to different types of tissues almost anywhere in the body.
The development of lymphoma outside the lymphatic tissue is called extranodal disease.
What are the types of lymphoma?
Lymphomas fall into two main categories: Hodgkin’s lymphoma (HL, formerly called Hodgkin’s disease) and other lymphomas (non-Hodgkin’s lymphomas or NHL).
These two types occur in the same places, can be associated with the same symptoms, and often appear similar on physical exams (for example, swollen lymph nodes).
However, they are easily distinguishable by microscopic examination of a tissue biopsy sample due to their different appearance under the microscope and their cell surface markers.
Hodgkin’s disease develops from a specific lineage of abnormal B lymphocytes. NHL can be derived from strange B or T cells and are distinguished by unique genetic markers.
There are five subtypes of Hodgkin’s disease and about 30 subtypes of non-Hodgkin lymphoma (not all experts agree on the numbers and names of these NHL subtypes).
Because there are so many different lymphoma subtypes, the classification of lymphomas is complicated (including microscopic appearance and genetic and molecular markers).
Many NHL subtypes are similar, but they are functionally different and respond to varying therapies with varying odds of a cure.
For example, the subtype of plasmablastic lymphoma is aggressive cancer that arises in the oral cavity of HIV-infected patients.
The follicular subtype is made up of abnormal B lymphocytes. In contrast, the anaplastic subtype comprises abnormal T cells, and cutaneous lymphomas locate abnormal T cells in the skin.
More than 30 subtypes of NHL have unusual names, such as mantle cell lymphoma and mucosa-associated lymphoid tissue (MALT) lymphoma.
However, the World Health Organization (WHO) suggests at least 61 types of NHL; subtyping is still a work in progress.
However, no matter how many subtypes the experts suggest, there are too many to discuss in detail in this article.
- A cold.
- Unexplained weight loss
- Night sweats.
- Lack of energy.
- Loss of appetite
- Short of breath.
- Back or bone pain.
- Blood in the stool or vomit.
- Blockage of urine flow.
These symptoms are nonspecific, and not all patients will have all of these potential symptoms. This means that a patient’s symptoms could be caused by conditions unrelated to cancer.
Causes vary widely and range from malignancy, infections, congestion, and infiltration of the spleen to other diseases, inflammatory conditions, and blood cell diseases.
Some of the more common causes of an enlarged spleen include the following:
- Liver disease (chronic hepatitis B cirrhosis, chronic hepatitis C, fatty liver, prolonged alcohol abuse).
- Blood cancers (lymphoma, leukemia, myelofibrosis).
- Infections (mononucleosis, bacterial endocarditis, malaria, AIDS, mycobacteria, leishmania).
- There is abnormal blood flow and congestion (splenic vein thrombosis, portal vein obstruction, congestive heart failure).
- Gaucher disease (a lipid storage disease).
- Blood cell disorders (sickle cell anemia, thalassemia, spherocytosis); inflammatory disease ( lupus, rheumatoid arthritis ).
- Polycythemia vera.
What tests do doctors use to diagnose lymphoma?
If a person has swelling or other symptoms, their healthcare provider will ask many questions about the signs.
A comprehensive exam follows these questions.
If, after an initial interview and examination, the doctor suspects that a patient may have lymphoma, the patient will undergo a series of tests designed to provide further clarification.
The patient could be referred to a specialist in blood diseases and cancer (hematologist/oncologist) in this work.
Blood is drawn for various tests. Some of these tests evaluate the function and performance of blood cells and essential organs, such as the liver and kidneys.
Certain chemicals or enzymes in the blood can be determined (lactate dehydrogenase [LDH]).
High levels of LDH in suspected NHL may indicate a more aggressive form of the disorder.
Other tests may be done to learn more about the subtypes of lymphoma.
If there is swelling (also called a lump or mass), a tissue sample from the node will be removed for examination by a pathologist. This is called a biopsy.
Several methods can be used to obtain a biopsy of a mass. Masses that can be seen and felt under the skin are relatively easy to biopsy.
A hollow needle can be inserted into the mass, and a small sample can be removed with the hand (called a core needle biopsy). This is usually done in the doctor’s office under local anesthesia.
Core needle biopsy does not always obtain a good quality sample. For that reason, many healthcare providers prefer a surgical biopsy.
This involves removing the entire swollen lymph node through a small incision in the skin.
This procedure is often done under local anesthesia but sometimes requires general anesthesia. Access is somewhat more complicated if the mass is not immediately under the skin but is inside the body.
The tissue sample is usually obtained laparoscopically. This means making a small incision in the skin and inserting a thin tube with a light and camera on end (a laparoscope).
The camera sends images of the inside of the body to a video monitor, and the surgeon can see the mass. A small cutting tool at the end of the laparoscope can remove all or part of the mass.
This tissue is removed from the body with the laparoscope. A pathologist (a doctor specializing in diagnosing disease by looking at cells and tissues) examines the tissue sample under a microscope.
The pathologist’s report will specify whether the tissue is lymphoma and the type and subset of lymphoma.
If there is no palpable mass in persistent symptoms, imaging studies will likely be done to determine if a group is present and, if so, how to direct a biopsy.
A plain X-ray can sometimes detect lymphoma in certain parts of the body, such as the chest.
This test provides a three-dimensional view and much more detail and can detect enlarged lymph nodes and other masses anywhere in the body.
Magnetic resonance imaging
Similar to computed tomography, MRI provides three-dimensional images with excellent detail.
MRI provides a better definition than CT scan in certain parts of the body, especially the brain and spinal cord.
Positron emission tomography (PET)
The PET scan is a newer alternative to the lymphangiogram and gallium scan to detect areas in the body that are affected by lymphoma.
A small amount of a radioactive substance is injected into the body and is then traced on the PET scan.
Radioactive sites on the scan indicate areas of increased metabolic activity, implying the presence of a tumor.
Bone marrow examination
Most of the time, a bone marrow exam is necessary to see if the bone marrow is affected by lymphoma. This is done by collecting a bone marrow biopsy.
Samples are taken, usually from the pelvic bone. A pathologist examines the bone marrow under a microscope. The bone marrow containing specific abnormal B or T lymphocytes confirms the lymphoma.
Bone marrow biopsy can be an uncomfortable procedure, but it can usually be done in a doctor’s office.
Most people are given pain relievers before the procedure to make them more comfortable.
Which is the treatment?
Healthcare providers, in general, are seldom engaged in the complete care of a cancer patient.
Most cancer patients receive ongoing care from oncologists but may be referred to more than one oncologist if any questions arise about the disease.
Patients are always encouraged to obtain second opinions if the situation warrants it. You can choose to speak with more than one oncologist to find the most comfortable one for you.
In addition to the primary care physician, family or friends can provide information. In addition, many communities, medical societies, and cancer centers offer online or telephone referral services.
Once one is established with an oncologist, there is ample time to ask questions and discuss treatment regimens.
The doctor will present each type of treatment, discuss the pros and cons, and make recommendations based on published treatment guidelines and their own experience.
Treatment for lymphoma depends on the type and stage. Factors such as age, general health, and whether one has been treated for lymphoma before are included in the decision-making process about treatment.
The doctor (with the opinion of other care team members) and family members decide what treatment to follow. Still, the decision is ultimately that of the patient.
Make sure you precisely understand what will be done, why, and what to expect from these options. As with many cancers, lymphoma is more likely to be cured if diagnosed early and treated promptly.
The most widely used therapies are combinations of chemotherapy and radiation therapy.
The goal of medical therapy for lymphoma is to complete remission. This means that all signs of the disease have disappeared after treatment.
Remission is not the same as cure. One can still have lymphoma cells in remission, but they are undetectable and cause no symptoms.
When in remission, the lymphoma can come back. This is called a recurrence. The length of remission depends on the type, stage, and grade of the lymphoma.
A remission can last a few months, a few years, or continue throughout life. Remission that lasts a long time is called durable remission, which is the goal of therapy.
The duration of remission is a good indicator of the aggressiveness of the lymphoma and the prognosis. A more prolonged remission generally indicates a better prognosis.
The remission can also be partial. This means that the tumor shrinks to less than half its size before treatment.
Medical treatment: radiation and chemotherapy
Standard first-line therapy (primary therapy) for lymphoma includes radiation therapy for most early-stage lymphomas or a combination of chemotherapy and radiation.
Chemotherapy is used primarily for later-stage lymphomas, with radiation therapy added to control the bulky disease.
Radiation therapy uses high-energy rays to kill cancer cells. It is considered a local therapy, which means that it should be used to identify areas of the body involved in tumor masses.
A radiation oncologist will plan and supervise the therapy. The radiation is aimed at the affected region or organ of the lymph node.
Occasionally, nearby areas are also irradiated to kill any cells that may have spread there undetected.
Depending on how and where the radiation is given, it can cause specific side effects such as fatigue, loss of appetite, nausea, diarrhea, and skin problems.
Radiation to lymph node areas can cause suppression of the immune system to vary degrees.
Irradiation of the underlying bone and bone marrow within the bone can suppress blood counts.
Radiation is usually delivered in short bursts five days a week over several weeks.
This keeps the dose of each treatment low and helps prevent or lessen side effects.
Chemotherapy is the use of powerful drugs to kill cancer cells. Chemotherapy is a systemic therapy that circulates through the bloodstream and affects all body parts.
Unfortunately, chemotherapy also affects healthy cells; this explains its known side effects. The side effects of chemotherapy depend partly on the drugs used and the doses.
Some people, because of the variability in the metabolism of chemotherapy drugs, tolerate chemotherapy better than other people.
The most common side effects of chemotherapy include suppression of blood counts, increasing susceptibility to infection, anemia, or blood clotting problems.
Other side effects may include nausea and vomiting, loss of appetite, hair loss, sores in the mouth and digestive tract, fatigue, muscle aches, and finger and toenail changes.
Medications and other treatments are available to help people tolerate these side effects, which can be severe.
It is essential to discuss and review the possible side effects of each chemotherapy drug in treatment with your oncologist, pharmacist, or oncology nurse.
Medications to decrease side effects should also be reviewed.
Chemotherapy can be given as a pill, but it is usually a liquid injected directly into the bloodstream through a vein (intravenously).
Most people who receive IV chemotherapy will have a semi-permanent device placed in a large vein, usually in the chest or arm.
This device allows the medical team quick and easy access to blood vessels, administering medications, and collecting blood samples.
These devices come in several types, generally called a “catheter,” “port,” or “central line.”
Experience has shown that drug combinations are more effective than monotherapy (use of a single drug).
Combinations of different drugs increase the chances that the drugs will work and lower the dose of each medicine, reducing the chance of intolerable side effects.
Several different standard combinations are used in lymphoma. The variety that one receives depends on the type of lymphoma and the experiences of the oncologist and the medical center where a person gets treatment.
Drug combinations are generally administered according to a set schedule that must be followed very strictly. In some situations, chemotherapy can be given in the oncologist’s office.
In other situations, one must stay in the hospital. Chemotherapy is given in cycles.
Standard treatment generally includes several cycles, such as four or six.
Disperse chemotherapy allows a higher cumulative dose to be delivered while improving the person’s ability to tolerate side effects.