What is Non-Hodgkin Lymphoma
Non-Hodgkin lymphoma is a type of cancer that originates in the cells of the lymphatic system – a collection of organs (lymph nodes or glands) and tissues that produce the cells responsible for immunity and defense. The distinction between non-Hodgkin lymphoma and Hodgkin lymphoma is made through biopsy.
These cells multiply uncontrollably and spread in a disorderly manner. Since lymphatic tissue is found throughout the body, non-Hodgkin lymphoma can start anywhere – but the most common sites of incidence are lymph nodes, bone marrow, gastrointestinal tract, skin, bones, and central nervous system.
Factors Associated with Non-Hodgkin Lymphoma
This disease can occur at all ages and becomes more common as people age. In the last 25 years, the number of cases has doubled, mainly among people over 60 years old.
Individuals more susceptible to non-Hodgkin lymphoma include those with immune deficiency (whether due to hereditary genetic disease, use of immunosuppressive drugs, or HIV infection), carriers of Epstein-Barr and HTLV1 viruses, and the bacterium Helicobacter pylori (which can cause gastric lymphomas), as well as individuals exposed to chemicals such as pesticides, aromatic amines, and radiation.
In 2020, the National Cancer Institute (INCA) estimated 12,030 new cases of non-Hodgkin lymphoma, with 6,580 in men and 5,450 in women. Globally, the number of new cases of this type of lymphoma reported by the World Health Organization (WHO) for 2020 was 544,352.
Subtypes of non-Hodgkin lymphoma
There are dozens of types of non-Hodgkin lymphomas. They are divided into two main groups: aggressive and indolent. These, in turn, have the following main subtypes:
Aggressive non-Hodgkin lymphomas:
- Diffuse large B-cell lymphoma – is the most common type, accounting for about 30% of cases. It occurs in older people, with rapid growth of lymph nodes in the neck, armpits, or groin, or in organs such as the liver, spleen, bone marrow, and brain;
- Central nervous system lymphoma – is rare and can be primary or secondary. The primary type starts in the brain, eyes, or meninges, while the secondary type starts in other parts of the body and spreads to the brain or meninges;
- HTLV-linked lymphoma – is caused by HTLV virus infection, from the same family as HIV. It can cause skin lesions and bone problems;
- Burkitt lymphoma – affects younger people and has extremely rapid growth;
- Mantle cell lymphoma – affects the lymph nodes, bone marrow, and spleen. It is more common in men, especially around the age of 60;
- Primary mediastinal large B-cell lymphoma – causes large thoracic masses. It is rare, affects more women in their 30s, and can cause breathing difficulty as it starts in the chest region;
- T-cell lymphoma – is much rarer than diffuse large B-cell lymphomas. It usually affects people over 60 years old. Among its most common types are: anaplastic large cell lymphoma, angioimmunoblastic lymphoma, extranodal NK/T-cell lymphoma
Indolent non-Hodgkin lymphomas:
- Follicular lymphoma – originating in the germinal center of the lymph node, it is the second most common subtype of non-Hodgkin lymphoma after age 60;
- Cutaneous T-cell lymphoma (mycosis fungoides) – is a type of lymphoma that arises in the skin and has itching as its main symptom;
- Lymphoplasmacytic lymphoma (Waldenstrom macroglobulinemia) – very rare, it is composed of small cells, affects lymph nodes and bone marrow, and produces immunoglobulin M (IgM);
- Marginal zone lymphoma – can affect various organs besides lymph nodes, such as the spleen, stomach, and ocular adnexa.
Symptoms and signs of non-Hodgkin lymphoma
Regardless of the type or subtype of non-Hodgkin lymphoma, the main symptoms of the disease are:
- Enlargement of lymph nodes in the neck, armpits, groin;
- Excessive night sweats;
- Fever;
- Itching of the skin;
- Unexplained weight loss of more than 10% of body weight.
Diagnosis and staging of non-Hodgkin lymphoma
Having observed the symptoms of non-Hodgkin lymphoma, the next step is to confirm its diagnosis and subtype. A biopsy of the affected area is performed, with the removal of a small portion of tissue (usually from the lymph nodes or any affected area) for analysis in a pathology laboratory.
Immunohistochemistry is essential for the proper classification of the lymphoma subtype. Accurate diagnosis and classification are crucial for determining the best treatment and achieving the best results.
Next, the disease is staged to determine which organs are affected. This is done through imaging tests such as computed tomography (CT), PET-CT, and, in some cases, bone marrow and cerebrospinal fluid analysis through punctures.
The staging of non-Hodgkin lymphoma uses Roman numerals (I, II, III, and IV) followed by A or B – where A indicates the absence of systemic symptoms (fever, night sweats, unexplained weight loss) and B indicates the presence of systemic symptoms.
In terms of numbering, the classification is as follows:
- I – there is only one chain of lymph nodes or one organ affected;
- II – two regions of the body on the same side of the diaphragm are affected by the lymphoma;
- III – both the region above and the region below the diaphragm are affected;
- IV – the lymphoma infiltrates the bone marrow or organs, such as the lungs and liver.
Non-Hodgkin Lymphoma Treatment
The treatment strategy will depend on the type of non-Hodgkin lymphoma. Most are treated with chemotherapy in combination with immunotherapy using monoclonal antibodies, and sometimes with radiation therapy.
Chemotherapy usually involves a combination of several drugs, administered orally or intravenously.
Immunotherapy uses medications against specific targets on the lymphoma cells (CD20, CD30).
Radiation therapy, on the other hand, uses radiation to eradicate or reduce the tumor burden in specific areas, to relieve symptoms, or to complement chemotherapy, reducing the risk of disease recurrence.
In special cases, high-dose chemotherapy and bone marrow or stem cell transplant may be necessary for the patient’s cure. Cellular therapy with the patient’s own genetically modified T lymphocytes (CAR-T cells) can also be used in case of relapse.
For indolent lymphomas, treatment options range from simple clinical observation to highly intensive treatments.
Prevention
The best way to prevent non-Hodgkin lymphoma is to avoid or eliminate physical factors that increase the risk of its development (exposure to chemicals such as pesticides, aromatic amines, benzidine, polychlorinated biphenyls, and carbon tetrachloride, or to high doses of radiation).
Additionally, controlling and treating diseases and conditions that make people more prone to developing it (immunity deficiency, whether due to hereditary genetic disease, use of immunosuppressive drugs, or infection by HIV, Epstein-Barr virus, HTLV1, and Helicobacter pylori) is important.
There is evidence that diets rich in vegetables and fruits may have a protective effect against non-Hodgkin lymphoma.
