Hodgkin Lymphoma is a form of cancer that arises in the lymphatic system where it appears as soft painless swellings or lumps commonly in neck, chest or arm pits.
Knowing about our lymphatic system helps us to better understand Hodgkin’s lymphoma. The lymphatic system is a part of our immune system which helps fight against infections and destroys damaged or abnormal cells. It is a network of lymph vessels and lymph nodes that work together to move lymph back into blood and organs that are spread throughout the body.
The lymph primarily contains infection-fighting white blood cells, known as lymphocytes. B-lymphocytes are one of the major categories of lymphocytes from where the Hodgkin’s lymphoma usually originates.
Abnormal multiplication of these cells results in accumulation of the same in the certain parts of the lymphatic system, like the lymph nodes, resulting in swelling. Although Hodgkin’s lymphoma can start almost anywhere, most often it starts in lymph nodes in the upper part of the body. The most common sites are in the chest, neck, or under the arms.
Types of Hodgkin’s Lymphoma
It is broadly classified into two groups namely:
- Classic Hodgkin’s’s lymphoma
- Nodular lymphocyte-predominant Hodgkin’s lymphoma
This typing is based upon the cellular pattern seen in the tumour as seen under the microscope. It is important to know about the type of hodgkin lymphoma as this helps determine the treatment one receives and the outcome we can expect from that treatment.
Classic Hodgkin’s lymphoma is more common and accounts for more than 90% of Hodgkin’s lymphoma cases in developed countries. The characteristic presentation of classic hodgkin’s lymphoma is the presence of cancerous cells called Reed-Sternberg cells, when a lymph node tissue sample is examined under a microscope.
Nodular lymphocyte-predominant Hodgkin’s lymphoma is rare and tends to grow more slowly, accounting for about 5% of Hodgkin’s lymphoma cases. The cancerous cells are large and are referred to as popcorn cells due to their appearance.
What are the symptoms of Hodgkin’s lymphoma?
One or more painless lumps developing because of swollen lymph nodes is a typical symptom. The common sites include neck, armpit or groin.
Some cases of Hodgkin’s lymphoma may present with a set of symptoms known as B symptoms, and include:
- Unexplained fever (100.4°F or above) that may come and go for several weeks
- Drenching night sweats
- Unexplained weight loss (more than 10% of body weight)
Other related generalized symptoms can include:
- Excessive tiredness
- Persistent itching
- Swelling becomes painful after drinking alcohol
However, many of these symptoms are also related to other illnesses, such as infections. A thorough diagnosis helps in differentiating Hodgkin’s lymphoma from other conditions.
What causes hodgkin’s lymphoma?
The exact cause of Hodgkin’s lymphoma remains unknown. However, it is most often diagnosed in people between 15 and 30 years of age and those over 55. Hence, it shows a bimodal age distribution. Based on the histologic subtype, the age distribution includes:
- Nodular lymphocyte-predominant HL (NLPHL): It mostly affects males. Peak incidence is noticed during the fourth and fifth decades of a person’s life, but can also be seen during the childhood.
- Classic Hodgkin’s lymphoma (cHL): The age and sex distribution in cHL depend on its subtypes.
Certain factors may also increase the risk for the condition. They include:
- Family history of lymphoma
- Male gender
- History of Epstein-Barr infection
- Weakened immune system
- Being overweight
How is Hodgkin’s lymphoma diagnosed?
Medical history and physical examination: The physical examination involves checking for specific signs of the disease, such as swollen lymph nodes (lymphadenopathy) and swelling in the spleen or liver.
Past medical history related to symptoms, such as fever, weight loss, night sweats, itchy skin (pruritus), and alcohol induced lymph node pain. Additionally, the past illnesses and medications of the person are noted.
Blood tests: Blood tests may not help in the diagnosis, but they can aid in cancer staging and treatment planning. A complete blood count (CBC) test is performed to check the blood count, as hodgkin’s lymphoma may result in decreased red blood cells (if HL invades bone marrow).
An erythrocyte sedimentation rate (ESR) test can be used to measure inflammation in the body provoked by hodgkin’s’s lymphoma. Other tests related to specific organ function (liver and kidney) or infections (HIV, Hepatitis B or C) may be recommended, if necessary.
Imaging studies: Imaging tests like computed tomography (CT) or positron emission tomography (PET) helps in cancer staging (to know the extent of disease).
Biopsy: It is a confirmatory test that involves collecting a sample of lymph nodes for histopathology examination to look for abnormal cells related to classic hodgkin’s lymphoma (Reed-Sternberg cells).
Bone marrow biopsy or aspiration: A bone marrow sample is obtained from the back of the hip bone and is examined to look for Hodgkin’s lymphoma cells.
Stages of Hodgkin’s lymphoma
The process of identifying the extent and spread of cancer in the body is known as staging. Staging helps in framing the treatment plan.
Following are the stages of hodgkin’s lymphoma (Based on Lugano Classification)
- Hodgkin’s lymphoma is confined to a single lymph node or lymphoid organ, such as the thymus (I).
- Hodgkin’s lymphoma in a single site other than the lymph system (I E).
- Hodgkin’s lymphoma is found in two or more lymph node areas present on the same side of the diaphragm (dome-shaped muscle below the lungs separating the chest from abdomen) (II).
- Hodgkin’s lymphoma spreads locally from lymph node area to nearby organ (II E).
- Hodgkin’s lymphoma found in lymph node areas on both sides of the diaphragm (III).
- Hodgkin’s lymphoma found in lymph nodes above the diaphragm and in the spleen.
- Hodgkin’s lymphoma spread extensively to at least one organ outside the lymph system, such as the liver, bones, or lungs (IV).
Each stage may also be assigned with letters A or B. If the case is presented with B symptoms, B is added to the stage and A is assigned when the B symptoms are absent. The letter E is added for limited stages of hodgkin’s lymphoma (I or II) that has spread to an organ outside of the lymph system.
Hodgkin’s’s lymphoma is referred to as bulky disease when the tumors in the chest measure at least one third of the chest in width or a tumor in other areas measures ten centimeters or more. This stage is usually labeled as X, and requires an intensive treatment.
Treatment and prognosis for Hodgkin’s lymphoma
The treatment regime depends on the type of Hodgkin’s lymphoma diagnosed. It also depends on the cancer stage, age and general health of the patient.
Chemotherapy and radiation therapy are predominantly used for the treatment. Depending on the condition either one or both treatments may be used.
Chemotherapy remains as the main line of treatment for Hodgkin’s lymphoma, other than nodular lymphocyte-predominant Hodgkin’s lymphoma. Several combinations of chemotherapy drugs are used in the treatment as different drugs can act on cancer cells in different ways.
The commonly used chemotherapy regimen (schedule and combination of different drugs) for classic Hodgkin’s lymphoma are:
It is the most commonly used chemotherapy regimen. This treatment includes the use of following drugs:
Other regimens include-
- BEACOPP regimen
- Stanford V regimen
Radiation therapy could be used as a part of treatment in the majority of cases, especially when the cancer is limited to one part of the body. Patients with early-stage nodular lymphocyte-predominant hodgkin lymphoma may require only radiation therapy.
Radiation therapy works well to destroy hodgkin lymphoma cells, however due to its late side effects, it is used to a lesser extent and in reduced dose compared to chemotherapy (as studies have shown chemotherapy alone can work well in certain cases). Involved site radiation therapy (ISRT) is the preferred approach to confine the radiation to the affected lymph nodes and the nearby areas to which the cancer has spread.
Immunotherapy can also be used to treat certain cases of hodgkin lymphoma. Monoclonal antibodies (Brentuximab vedotin or Rituximab) and Immune checkpoint inhibitors (Nivolumab or Pembrolizumab) are some of the common types of immunotherapies used in the treatment.
Hematopoietic Stem Cell Transplantation (HSCT):
Stem cell transplantation is done when the condition does not improve with chemotherapy and/or radiation therapy or if the condition recurred after the treatment.
Regular follow-ups are initiated once the treatment ends, to monitor the recovery and to check for the cancer recurrence. Hodgkin’s lymphoma is highly treatable in its early stages. The five-year survival rate for people with early stage hodgkin’s lymphoma is about 92%, which reduces in later stages (78%).