Lymphoma

What is lymphoma ?

Lymphoma is a cancer of the immune system that primarily develops in the lymph nodes. It involves a specific type of white blood cell known as lymphocytes.

Lymph nodes are small, bean-shaped organs that are part of the lymphatic system and are distributed throughout the body. They contain immune cells, particularly lymphocytes, which are ready to respond to potential external threats or attacks.

When an error occurs in the production of lymphocytes, it can lead to the creation of an abnormal cell. This abnormal cell escapes normal regulatory control, and it may have the ability to multiply rapidly and survive longer than normal cells. This can result in the formation of a tumor, known as lymphoma.

Interview with Doctor Clémentine Sarkozy

In mainland France, lymphomas account for half of all hematologic malignancies. This corresponds to 6% of all new cancer cases.

Types of lymphomas

Two types of lymphoma exist and are different both in their appearance and in their management.

Hodgkin lymphoma (HL)

HL was the first type identified by Sir Thomas Hodgkin in 1832.

It is characterized by the presence of large, atypical cells known as Reed-Sternberg cells.

Hodgkin lymphoma is a rare cancer, with approximately 1,900 new cases per year in France (0.5% of all cancers). Additionally, it is more common in young adults.

Non-Hodgkin lymphoma (NHL)

NHL accounts for 90% of lymphoma cases, with a median age of occurrence around 60 years. Some NHLs are termed indolent, meaning they have a relatively slow progression but are prone to frequent relapses. In contrast, aggressive NHLs are characterized by rapid progression and have a cure rate of around 60%.

Causes and risk factors

In most cases, no specific causal factor has been identified.

In the workplace, exposure to pesticides, organic solvents (such as benzene, chlorinated solvents, hair dyes), and wood dust has often been associated with an increased risk of lymphoma.

Since 2015, a decree has recognized malignant non-Hodgkin lymphoma caused by pesticides as an occupational disease under the agricultural regime.

In the general environment, exposure to UV rays, ionizing radiation, and dioxins are suspected of increasing the risk of lymphoma, though a definitive causal link has not been established.

Certain infectious agents may be associated with the development of lymphoma, either through a direct oncogenic role (such as the Epstein-Barr virus or HTLV-1) or chronic antigenic stimulation (such as certain bacteria like Helicobacter pylori).

Screening

Since the causes of NHL are unknown, it is not yet possible to screen for or detect these cancers early in the general population.

In cases of high risk for developing the disease, close monitoring may be implemented to detect early signs of lymphoma.

Symptoms

Persistent enlargement of one or more lymph nodes can cause swelling in the affected area (such as the neck, underarm, or groin).

Lymphomas can also develop in extranodal regions, including lymphoid tissue associated with mucous membranes, the spleen, bone marrow, or other organs (such as the brain or testicles), which may lead to symptoms depending on the precise location, such as cough and diarrhea.

The patient may also experience a general decline in health, including :

• Weight loss
• Fatigue
• Fevers (especially in the evening)
• Night sweats (especially at night)

Hodgkin lymphoma may be revealed by rarer symptoms such as :

• Unexplained itching
• Pain in the lymph nodes after consuming alcohol

Diagnosis

The diagnosis is confirmed by a biopsy and histopathological analysis. The initial staging workup will then include a CT scan and/or PET scan, laboratory tests, and pre-treatment assessments.

In the context of chemotherapy, a consultation for fertility preservation will be carried out.

Treatments

Treatment choices primarily depend on the type of lymphoma, the stage, the size of the lymph nodes, certain biological parameters, the patient's overall health, age, and, of course, their medical history.

In about 30% of cases of indolent lymphomas, such as follicular lymphoma, if the patient does not have symptoms, they may be monitored without initiating treatment, known as "watchful waiting."

In contrast, when treatment is required for an aggressive lymphoma, it will typically involve chemotherapy combined with immunotherapy. Chemotherapy is often a combination of drugs and is administered intravenously through an implanted port.

For Hodgkin lymphoma, it is not uncommon to add radiation therapy, which uses ionizing radiation to destroy cancer cells, after 3 or 4 cycles of chemotherapy. In the event of a relapse, management is evolving with increasing options based on immunotherapy and targeted therapy, although chemotherapy followed by autologous stem cell transplant remains a standard option for first relapses.