Hodgkin's Vs Non-Hodgkin's Lymphoma: Differences

A lymphoma is a cancer that arises from the lymphocytes

Lymphocytes are the white blood cells that are responsible for ensuring our body’s immunity and defense against external micro invaders. A lymphoma can develop anywhere lymphoid tissue is found: in the spleen, bone marrow, in the lymph nodes or other organs. Compared to leukemias, lymphomas are solid tumors of lymphocytes, whereas leukemias are not solid tumors, are affect mostly circulating lymphocytes (compared to fixed lymphocytes as in lymphomas).

Because lymphomas develop from B lymphocytes, when someone is suffering from one, he therefore experiences a myriad of symptoms referred to as “B-symptoms”: weight loss, fever, night sweats, decreased appetite, etc.  And these occur in all lymphomas. However, depending on how aggressive the lymphoma is, the symptoms might progress slowly or quickly and the condition could quickly deteriorate.

How do you know which one is Hodgkin’s or Non-Hodgkin’s?

Hodgkin’s Lymphoma derives its name from Mr. Thomas Hodgkin, a graduate of the University of Edinburgh who first described the disease. A priori, all lymphomas were found to have the same characteristics (cell surface markers, symptoms, metastasis profiles, etc.). While he was working as a Museum Curator at the Guy’s Hospital, Mr. Thomas Hodgkin initiated a study on seven patients who were found to suffer from painless lymph node enlargement. Reports were made of enlargement of lymph nodes in the neck region, as well as of the spleen. Later on, cytological analysis of those lymph nodes revealed a rather interesting appearance of the cells: the cancerous cells were binucleated (two nuclei) resembling an owl’s eye. They are thought to be B cells that have not undergone hypermutation to express antibodies. These cells are called “Reed-Sternberg cells”, named after Dorothy Reed Mendenhall and Carl Sternberg who first described the definitive microscopic findings of Hodgkin lymphoma. With that said, the Reed-Sternberg cells are almost always confirmatory for the presence of Hodgkin Lymphoma, thus differentiating it from any other lymphomas. Henceforth, any other lymphoma without the presence of the Seed-Sternberg cell is a Non-Hodgkin Lymphoma (NHL).

Although the presence of the Reed-Sternberg cell is the confirmatory sign for the diagnosis of Hodgkin Lymphoma, other factors could also help us to differentiate between Hodgkin Lymphoma and Non-Hodgkin lymphoma while waiting for a confirmatory biopsy.

Causes of lymphoma

It is commonly believed that the highest risk factor to developing a lymphoma is a family history of the same. This is due to the fact that mutation in B-cells related genes are inherited along generations.

This is probably due to the fact that the EBV trigger B lymphocytes, thus causing accelerated proliferation and therefore increasing the risk of cancer.

See Also: Low White Blood Cells Count

Location of the tumors

In Hodgkin Lymphoma, the affected lymph nodes are contiguous. In other words, they follow a specific chronological pattern” starting in the shoulders, then the neck, then the chest. Non-Hodgkin lymphomas however could arise anywhere and affect any type of lymph nodes at a given time, with no specific pattern.

Symptoms Of Hodgkin's And Non-Hodgkin's Lymphoma

For Hodgkin and NHL, the symptoms are the same. However, one key feature in Hodgkin Lymphoma is the Pel-Ebstein fever or cyclic fever, which increases and then suddenly decreases within 1 – 2 weeks, and starts all over again.

A very important symptom in all types of lymphomas is the painless enlargement of the lymph nodes (in the neck, mandible, axillary, shoulder, etc.).

Then, fever, chills, night sweats and weight loss might ensue. As the disease progresses, the enlarged lymph nodes could become painful, leading to what is referred to as “painful lymphadenopathy”. Some patients could also experience intractable back pain that doesn’t seem to be relieved by any medications. Also, bleeding under the skin (ecchmymoses, purpurae or petechiae) could also be observed in patients suffering from lymphomas.

Prevalence

Hodgkin disease is much more prevalent among specific age groups. For instance, people who are between 15 and 30 and those above the age of 50 are at higher risk of developing Hodgkin disease compared to the general population. On another note, Non-Hodgkin lymphomas affect all age groups, independently of one another.  In both cases, the gender predilection is known: men are at a higher risk of developing Hodgkin or Non-Hodgkin disease compared to women.

Treatment

Like in the case of any other malignancy, treatment depends on the type of cancer, the grade and the stage of the disease. However, on a general note when it comes to lymphomas, high grade lymphomas are more curable and better treated than low grade tumors. High grade NHL responds well to aggressive chemotherapy following the CHOP or R-CHOP regimens: Cyclophosphamide, Hydroxydaunorubicin, Oncovin (Vincristine) and Prednisone. Examples of high grade lymphomas include Burkitt Lymphoma.

Unfortunately, low grade lymphomas are incurable. However, because they progress very slowly, watchful waiting is generally the first step in management, especially because those lymphomas cannot be treated. Also, the patient could go on for several years (even most of his life) without ever experiencing symptoms, and if that is the case there would be no point in initiating chemotherapy since it would not be curative, as the risks of chemotherapy would outweigh the benefits. However, when the patient starts to experience symptoms, then chemotherapy or radiotherapy are the two best options to alleviate the symptoms (such as painful lymphadenopathy).

However, if metastases have occurred, local radiotherapy should be combined to systemic chemotherapy for the best results. The commonly followed chemotherapeutic regimen for Hodgkin disease is the ABVD regimen: Adriamycin, Bleomycin, Vincristine, Dacarbazine.

See Also: What does high white blood cells count indicate?

Prognosis

It is possible that the fact that Hodgkin disease has been the object of intensive studies contributes to its highest cure rates compared to NHL. In fact, the 5 years survival rate of patients with Hodgkin lymphoma is between 60-90%, depending on the cancer grade at the time of the diagnosis. As for Non-Hodgkin Lymphomas, the prognosis depends on time stage and grade of the cancer at the time of diagnosis.