lymphoma in children

Leukemia and lymphoma



Pediatric cancers have very different characteristics of adult tumours. The most common in children are blood cancers or leukemias. Some forms of cancers of the lymphatic system, lymphomas, also affect children especially.
Sick child

Childhood leukemia
Leukemias represent the most common cancers in children (almost one in three cases). They are the result of an anomaly in the development of hematopoietic stem cells of the bone marrow (precursor cells of all blood cells: red and white cells, platelets). These stem cells can evolve into two large cell types:

Lymphoid stem cells, which then turn into lymphocytes (white blood cell types). Three types of lymphocytes exist: B lymphocytes, T lymphocytes and NK lymphocytes;
Myeloid stem cells, which produce red blood cells, other types of white blood cells (granulocytes, monocytes) and platelets.
Leukemias are a particular cancer because the tumor cells invade the whole organism from the bone marrow, thanks to the blood flow.

To know! There are acute and chronic forms of leukemia. Acute, child-specific leukemias, which are rarer in adults, begin suddenly and develop within a few days to a few weeks. Chronic leukemias develop slowly in several months or years and are more specific to adults (very rare in children).

Different types of leukemia
Depending on the type of cell affected, several forms of leukemia are defined:

Acute lymphoid or lymphoblastic (LAL) leukemias (about 85% of childhood leukemia cases), more frequent in boys;
Acute myeloid or myéloblastiques leukemia (LAM), affecting girls more often.
Depending on the stage of evolution of tumor cells, several categories of LAL and LAM are defined by specialists and are more or less common in children.

Risk factors for childhood leukemia
Pesticides vignePlusieurs Risk factors for leukemia have been identified in children:

The existence of genetic syndromes (resulting from the mutation of one or more genes), in particular Down syndrome, Bloom syndrome, Fanconi anemia, ataxia-telangiectasia, neurofibromatosis type 1, Wiskott-Aldrich syndrome, Klinefelter syndrome, Li-Fraumeni syndrome or Shwachman-Diamond syndrome;

A history of leukemia in siblings;
Exposure to high doses of radiation;
Prior treatment with radiotherapy or chemotherapy;
A high weight at birth (> to 4 kg).
In parallel with these known factors, other aspects could play a role in the occurrence of leukemia, although this link has not yet been scientifically proven: exposure to certain radiations or electromagnetic fields, pesticides, Cigarette smoke, alcohol, benzene (carcinogenic solvent) or maternal exposure to certain paints.

Childhood leukemia Symptoms
Symptoms usually appear quickly within a few days or weeks. Childhood leukemias may manifest differently depending on the type of leukemia involved, but they all have the following signs in common:

fatigue;
a pallor;
Frequent infections
Persistent and often moderate fever
Bruises (bruises), frequent bleeding (nose, gums) and red patches on the skin (petechiae);
Bone or joint pain, which may cause limping;
Swelling of the abdomen, linked to increased spleen or liver volume
Loss of appetite associated with weight loss
Swelling of the lymph nodes (adenopathies);
A rebellious cough, sometimes accompanied by breathing difficulties;
Edema of the face and arms.
Other symptoms may occur, especially if leukemia spreads to the central nervous system or to certain organs.

Diagnosis and prognosis of leukemias

Taking blood from a child more often, parents are consulted as a result of a rapid deterioration in the state of their child's health. The diagnosis of leukemia is based on a large number of medical examinations, which on the one hand confirm leukemia, and on the other hand allow to determine its type and stage of evolution. These exams are necessary to put in place the most appropriate care for the child's illness.

These exams are as follows:

Blood tests (blood cell counts, determination of blood clotting factors, dosage of enzymes and various compounds);

A bone marrow biopsy on which different laboratory tests are performed to identify tumor cells and disease progression;

A lumbar puncture to analyze the cerebrospinal fluid (in which the brain and brains are bathed) and determine whether leukemia has reached the central nervous system;

A testicular biopsy if the doctor suspects a testicular injury;

Imaging examinations (X-rays, ultrasounds, scans and MRI (magnetic resonance imaging)) to investigate possible organ damage (lymph nodes, liver, spleen, testicles, skin, gums, brain, lung).

From all these elements, the multidisciplinary team, which takes care of the child, can establish the precise diagnosis of the disease, indicate a prognosis to the family (probability of progression of the disease) and set up the treatments Adapted.

Several factors can influence the prognosis of the disease:

Age: Children aged 1 to 9 years have a better prognosis than younger or older children;

The number of white blood cells at the time of diagnosis: The prognosis is better for children whose number is less than 50 000 cells/mm3;

The central nervous system or the testicles;

The existence of chromosomal or genetic anomalies;

Sex

The response to the treatment.

On average, after 5 years, 89% of children aged 0 to 14 years are still alive after acute lymphoblastic leukemia, compared with 67% in the case of acute myeloid leukemia.

Treatment of childhood leukemia

The management of leukemias involves different types of anti-cancer treatments:

The purpose of drug chemotherapy is to destroy the maximum number of tumor cells. The drugs are administered by a central venous catheter, set up in the child's body prior to the first treatment session;

Bone marrow grafting is used to replace the bone marrow of the child destroyed by the tumor or by the treatments;

Radiation therapy occurs when some organs have been invaded by tumor cells.

For each type of leukemia and each stage of disease progression, standardized treatment protocols have been defined by national, European or international expert committees. These protocols define the chemotherapy medications to be used, their dosage and the number of chemotherapy sessions, but also the use of radiotherapy and bone marrow transplant.

Chemotherapy medications are powerful and often cause significant, sometimes irreversible, side effects. They are very variable according to the active principles, but it is possible to mention the main ones:

Medullary Aplasia (Stopping the functioning of the bone marrow);

Pain in the mouth

fatigue;

Loss of appetite, nausea and vomiting

Constipation or diarrhea

Weight loss

Hair loss

Skin problems

Muscle or joint pain

edema;

Nervous system disorders

Liver problems

Sometimes very serious allergic reactions;

Heart attack

Reproductive and sexual disorders with a significant risk of sterility.

Marrow OsseuseLa bone marrow transplant is a complex procedure, because it requires the child to be in a medullary aplasia, i.e. its bone marrow no longer produces any red or white blood cells or platelets. This aplastic stage is either the result of the evolution of the disease or obtained through intensive chemotherapy in preparation for the intervention (conditioning). The child must then receive frequent blood transfusions and stay in a sterile hospital area, as the slightest infection is likely to cause her death (his body is unable to defend himself). The grafted bone marrow comes from either a family member (parent, sibling) or an anonymous donor.

After treatment, children are monitored very regularly for several years, both for early detection of possible recurrence, but also for the identification of long-term side effects of treatments.

To know! A child is said to be in remission, when no signs of leukemia are observed after 4-6 weeks of induction chemotherapy (first round of treatments). The risk of recurrence, sometimes several years after the initial illness, is more or less important depending on the type of leukemia.

The child's Lymphomas

Lymphomas are cancers of the lymphatic system, in which tumor cells are abnormal lymphocytes (white blood cells). This system consists of the spleen, the thymus, the tonsils, the adenoids vegetation, the bone marrow and a network of lymph nodes scattered throughout the organism. All these organs are connected by a network of lymphatic vessels, in which the lymph (liquid close to the blood plasma) circulates. Lymphatic tissue is also present in some organs, such as the stomach, intestine or skin. The lymphatic system contributes to the proper functioning of the circulatory system and immune systems.

Two major types of lymphoma are considered:

Hodgkin (LH) lymphomas, which preferentially affect adolescents and adults;

Non-Hodgkin (NHL) lymphomas, which are more common among children under 15 years of age, are subdivided into four main subtypes.

Non-Hodgkin lymphomas of the Child:

Non-Hodgkin's lymphoma subtype frequency affected children

Burkitt lymphoma (B lymphocytes) 35 to 40% of cases more often boys, between 5 and 15 years of age.

Lymphoblastic lymphoma (T-lymphocytes or B-cell precursors) 25 to 30% of adolescent cases

Large cell anaplastic lymphoma 10% of cases young children

Large cell diffuse B lymphoma 15 to 20% of cases between 10 and 20 years

Hodgkin lymphomas in children

Hodgkin's lymphoma is associated with the development of abnormal B lymphocytes, called Hodgkin cells and Reed Sternberg. Several subtypes of LH are considered, depending on different characteristics of tumor cells. LH can affect children, regardless of age, even if it is rare before 5 years. It is more common among teenagers and reaches both boys and girls.

Risk Factors

Child pauvrePlusieurs Risk factors have been identified for the child's Hodgkin's lymphoma:

Epstein-Barr virus Infection (virus responsible for infectious mononucleosis);

A family history of Hodgkin (LH) H lymphomas;

A weakened immune system, due to HIV infection, the taking of immunosuppressive drugs, or a congenital immune deficiency.

Other factors may influence the occurrence of Hodgkin's lymphoma, but the link has not been scientifically established: reduced exposure to early childhood infections or precarious socio-economic status.

The symptoms of Hodgkin's lymphoma

Hodgkin's lymphoma is the source of a number of characteristic symptoms, in particular:

Swelling of the lymph nodes (adenopathies);

Fatigue, weakness and a general impression of discomfort;

Loss of appetite

Itchy skin (pruritus).

Other symptoms may be associated, depending on the subtype of the disease and its location in the organism:

Fever above 38 °c without apparent cause;

Night sweats;

Unexplained weight loss (at least 10% of body weight over the last six months);

Shortness of breath, cough or chest discomfort;

Digestive disorders, abdominal pain and swelling of the abdomen;

sore throat and difficulty swallowing

Swelling of the feet and legs

Repeated infections

Bleeding or bruising.

The diagnosis of Hodgkin's lymphoma

MRI cancer the diagnosis of Hodgkin's lymphoma requires several medical examinations to confirm the origin of the symptoms and determine the type of lymphoma:

Blood tests

Biopsy of one or more lymph nodes to detect and characterize tumor cells;

A bone marrow biopsy to determine the stage of disease progression;

Imaging examinations (X-rays, scanners, MRI) to assess the spread of lymphoma;

A bone scan, to detect possible metastasis.

Based on the overall results, the multidisciplinary team will be able to assess the stage of lymphoma, according to Ann Arbor's classification, and determine the level of risk of cancer, in order to set up the most suitable catch for the child's case.

The treatment of Hodgkin's lymphoma

The management of this type of lymphoma is defined by standardized protocols according to the age of the child, the nature of the tumor and the stage of evolution of the disease. The treatment can implement:

Chemotherapy with one or more medications

Radiotherapy Sessions

A bone marrow transplant;

Surgery to extract the affected lymph nodes.

Several factors are considered in determining the prognosis of Hodgkin's lymphoma in children. On average, 5-year survival is 98% for children aged 0 to 14.

Non-Hodgkin lymphomas in children

Four major subtypes of non-Hodgkin lymphomas can primarily affect children. Other subtypes, much rarer, can also be encountered, such as post-transplant lymphoproliferative syndrome, which occurs after organ transplantation.

Non-Hodgkin's lymphoma (NHL) can affect any region of the body, as lymphocytes are dispersed throughout the body through lymphatic circulation.

Risk factors for non-Hodgkin lymphomas

Child cancer MaladeUn Link could be established between several individual factors and the occurrence of non-Hodgkin's lymphoma:

A weakened immune system, linked to HIV infection or the taking of immunosuppressive therapy;

Hereditary immune deficiency (ataxia-telangiectasia, Wiskott-Aldrich syndrome, X-chromosome-related lymphoproliferative syndrome, Chediak-Higashi syndrome or severe combined immune deficiency);

Infection with Esptein-Barr virus (infectious mononucleosis virus);

A personal history of Hodgkin's lymphoma.

For other factors, a link to non-Hodgkin's lymphoma is advanced, but not scientifically verified:

Exposure to pesticides

Exposure to smoking in utero.

Symptoms of non-Hodgkin lymphomas

Non-Hodgkin lymphomas are manifested by a wide variety of symptoms depending on the region of the affected organism:

In the abdomen: swelling associated with pain, alteration of intestinal transit (constipation, diarrhea), nausea or vomiting, loss of appetite;

At the Mediastinum (part of the thorax between the lungs and containing the heart): shortness of breath, chest pain, breathing difficulties, noisy breathing, coughing, swelling of the lymph nodes of the thorax, a Feeling of general discomfort. In some cases, a fatal complication may occur, the compression syndrome of the upper vena cava, which results in coughing, difficulty breathing, headache, dizziness, loss of consciousness and edema of the part upper body;

At the skin level: the presence of red or violet masses under the skin, which cause itching;

At the head and neck: swelling of the lymph nodes, nasal obstruction, swelling of the tonsils and ear aches sometimes associated with hearing loss;

In the central nervous system: headaches, vomiting, visual disturbance, mental confusion, convulsions, loss of limb motor skills, urinary disorders, back pain and numbness in the extremities of the limbs;

At the bone marrow level: repeated infections, frequent bleeding or bruising, paleness and shortness of breath.

Fever in the parallel child, general signs may accompany these symptoms, in particular:

A fever with no apparent cause;

Important night sweats;

A weight loss of more than 10% of body weight over the last six months.

Diagnosis of non-Hodgkin's lymphoma

To establish the diagnosis of the disease, define the type of lymphoma and determine the stage of evolution, different medical examinations are indispensable:

Blood tests

Imaging examinations (X-rays, scanners, ultrasounds, MRI) to determine the regions of the organism affected by cancer;

Biopsy of lymph nodes or tumours present in the thorax or abdomen;

A bone marrow biopsy to define the type of lymphoma and the stage of evolution;

A lumbar puncture to investigate possible brain damage;

A sampling and analysis of the pleural fluid (liquid present in the thorax) or peritoneal (liquid contained in the abdomen);

A bone scan to detect possible bone metastasis.

From all these elements, the multidisciplinary team will be able to establish the precise diagnosis of the cancer, evaluate its prognosis and set up a suitable management.

Treatment of non-Hodgkin's lymphoma

The child's non-Hodgkin lymphomas generally respond well to chemotherapy drugs, which are the primary and often unique treatment of these cancers. Surgery may, in certain contexts, be necessary, before or after chemotherapy, to remove certain lymph nodes or to extract tumors from the abdomen or thorax. Radiotherapy is only used very rarely. Bone marrow transplant is reserved only for recurrences of non-Hodgkin lymphomas.

Several factors come online to estimate the prognosis of non-Hodgkin's lymphoma in children. On average, for children aged 0 to 14 years, survival at 5 years is 88%.