Hodgkin lymphoma, also called Hodgkin disease, is a type of cancer that originates in the lymphatic system – a collection of organs (lymph nodes or ganglia) and tissues that produce the cells responsible for immunity, and the vessels that carry these cells throughout the body.
Lymphoma arises when the lymphocytes, which are present in the lymph nodes and have the function of protecting the body against bacteria, viruses, and other dangers, turn into a malignant cell called a Reed-Sternberg cell. It is this cell that triggers the inflammatory reaction that generates a cluster of malignant and normal cells that form the tumor mass.
In Hodgkin lymphoma, the cells multiply uncontrollably and spread in an orderly fashion from one group of lymph nodes to another through the lymphatic vessels. Over time, they can spread to nearby tissues and, if left untreated, to other parts of the body.
The disease most often appears in the lymph nodes of the neck, chest, and armpits. Men are more likely to develop Hodgkin lymphoma than women, and the age groups in which cases are most common are from 15 to 39 years and from 75 years onward.
For 2020, INCA (National Cancer Institute) has estimated 12,030 new cases of non-Hodgkin lymphoma in Brazil. Worldwide, the number of new cases of this type of lymphoma presented by the WHO (World Health Organization) for 2020 was 83,087.
Types of Hodgkin lymphoma
There are two types of Hodgkin lymphoma:
- Hodgkin lymphoma with nodular lymphocyte predominance – affects 5% of patients with the disease and is more frequent in young adults. It does not always manifest symptoms, but when they do occur, they are those common to lymphoma. It is rarely found outside the lymph nodes, being more common in the neck and chest regions. It has a high chance of cure and a 3% risk of turning into non-Hodgkin lymphoma; and
- Classic Hodgkin’s lymphoma – affects 95% of patients with the disease and is divided into four subtypes:
- Nodular sclerosis – constitutes about 60% of all Hodgkin lymphoma cases and is the most common type in adolescents and young adults. It usually manifests in the cervical, supraclavicular and chest region and is highly curable;
- Lymphocyte-rich – similar to that of nodular lymphocyte predominance, but has more features in common with the classic one;
- Mixed cellularity – it is the second most frequent subtype, with 25% of all cases of Hodgkin lymphoma. It is more common in children up to 14 years old and adults between 55 and 74 years old, and also prevalent in people with immune system disorders, such as HIV carriers (human immunodeficiency virus). It is usually associated with a more advanced stage of the disease, but is highly curable;
- Lymphocyte depletion – it occurs mainly in the elderly and in people with HIV, and patients may have extensive disease without lymph node enlargement. It is not uncommon for this diagnosis to be confused with non-Hodgkin lymphoma.
Symptoms and signs of Hodgkin lymphoma
The symptoms of Hodgkin lymphoma depend on its location. If it develops in the superficial lymph nodes of the neck, armpits, and groin, painless localized swellings (bumps) form. If it occurs in the chest region, cough, shortness of breath, and chest pain may occur. In the pelvis or abdomen, the symptoms are usually abdominal discomfort and distension.
Other warning signs that can be added to the localized symptoms are systemic symptoms: fever, tiredness, night sweats, weight loss for no apparent reason, and itchy body.
Diagnosis of Hodgkin lymphoma
Once the symptoms of Hodgkin lymphoma have been observed, the next step is to confirm its diagnosis and type/subtype. A biopsy is taken from the affected area, with removal of a small part or all of the lymph node, and its pathological test.
The ideal is to perform an excisional biopsy, which is the entire removal of the affected lymph node or tissue – in this way the architecture of the lymph node is preserved, which facilitates its classification. In certain situations, however, incisional biopsy (removal of a small portion of the affected tissue) may be the best alternative.
Imaging tests are also necessary to determine the extent of the disease, that means, the lymphoma stage. PET-CT is currently the indicated test for this function; however, since it is not available in most health centers in Brazil, contrast-enhanced CT scans can be used for the same purpose. A chest X-ray can detect the presence of mediastinal involvement.
A bone marrow biopsy should be performed only in cases where PET-CT scan was not possible and stage IB-IIB, III, or IV were detected by CT scan. Bone marrow biopsy is not necessary in stages IA and IIA.
The staging of Hodgkin lymphoma is classified from one to four in Roman numerals (I, II, III, and IV), jointly by A or B – A being the absence of systemic symptoms (fever, tiredness, night sweats, weight loss for no apparent reason, and body itching) and B being the presence of systemic symptoms.
As for the numbering, the classification is:
- I – there is only one lymph node chain compromised, which means that only one region of the body is affected (this can be the cervical or axillary region);
- II – two regions of the body are affected by lymph nodes, both on the same side of the diaphragm (only above or only below – axillae and neck, for example);
- III – both the region above and the region below the diaphragm are involved (the disease is spread – neck and groin, for example);
- IV – the lymphoma has already infiltrated the lymphatic tissue and some other organ, such as the stomach, liver, kidney, or central nervous system.
The classic treatment for Hodgkin lymphoma is a polychemotherapy (chemotherapy with multiple drugs), with or without associated radiotherapy. The number of cycles will depend on the assessment of the initial tumor stage and the result of the interim PET-CT, and the routine regimen or protocol is called ABVD. The acronym identifies the initials of the medications used: Adriamycin, Bleomycin, Vinblastine, and Dacarbazine, sometimes associated with Brentuximab Vedotin. Bleomycin is not used in patients with advanced and high-risk stages.
If the disease returns or there is no response to treatment, the alternatives are multidrug therapy and bone marrow transplantation.
Approximately 70-80% of patients are currently cured.
There is no effective form of prevention for Hodgkin’s lymphoma.