About lymphoma

Lymphoma is not one cancer but refers to many different malignancies which all originate from lymphocytes, which are white blood cells that play an important role in our immune system. Humans have 3 main types of lymphocytes: T-cells, B-cells and NK cells, however within each of these groups many subsets of lymphocytes are defined, an of which may cause lymphoma.

Overall lymphoma is a relatively common cancer, diagnosed in approximately 800 New Zealanders every year; however some lymphomas are very rare. Immune suppression, autoimmune diseases, ageing, ethnicity, radiation exposure and certain infections (viral and bacterial) are known to predispose to some types of lymphomas; however in most patients no cause for their lymphoma is identified. Familial (i.e. genetic or inherited) lymphomas are rare.

Lymphoma can arise in any part of the body, although usually lymph nodes are involved. Patients can present with a huge variety of signs and symptoms which can often mimic other diseases; therefore recognising lymphoma can be challenging and patients are occasionally frustrated by multiple tests and a delay in diagnosis. Conversely, many patients with low grade lymphomas have no symptoms and enlarged lymph nodes are found incidentally when scans or blood tests are performed for other indications.

A definitive diagnosis of lymphoma is made by performing several types of tests on a biopsy of the involved tissue. Over 50 types of lymphoma are known, and as the treatment and prognosis of each type of lymphoma may vary considerably, it is vital to obtain an accurate diagnosis. When a diagnosis of lymphoma is established, staging investigations determine the extent of lymphoma throughout the body. Staging contributes to treatment planning and helps predict outcome. Staging investigations include a “full body” CT scan, bone marrow biopsy, and blood tests - including testing for some viral infections. Occasionally special scans (such as MRI or PET) or a lumbar puncture may be required. Unlike other types of cancer it is not only the stage which predicts prognosis and in some case even very advanced disease is considered curable.

Lymphoma staging:

Stage I  Single nodal area or structure
Stage II Two or more nodal areas on the same side of the diaphragm
Stage III Nodal areas on both sides of the diaphragm
Stage IV Extranodal involvement
B Symptoms Fever >38°C, weight loss >10% in the preceding 6 months, drenching night sweats

The type of lymphoma/biopsy results,  staging investigations and patient’s overall heath determine the treatment options, which may include monitoring only (for low grade disease), radiotherapy, chemotherapy, bone marrow/stem cell transplant and supportive care (such as blood transfusions). Some types of lymphomas have high cure rates while others are considered incurable. Many lymphomas have a validated prognostic scoring system which can help in predicting outcomes.

Lymphoma classification:

There are several components to lymphoma classification. The following information is not exhaustive but outlines the basic framework for classification. Comprehensive diagnostic criteria for lymphoma have been published by the World Health Organisation. 

1. The type of lymphocyte involved: In Hodgkin lymphoma, unique malignant B-lymphocytes called Reed-Sternburg and Hodgkin cells are seen. These cells are not found in any other types of lymphomas, which are therefore referred to as non-Hodgkin lymphomas (NHL). NHL is further classified as to the type of lymphocyte involved e.g. B-cell vs T-cell.

2. The site of lymphoma: For example, central nervous system lymphoma or cutaneous (skin) lymphoma

3. The rate of growth: Although there are exceptions to this rule, typically fast growing or aggressive tumours are composed of large lymphoma cells, while slow growing or indolent lymphomas are most often composed of small cells.

B-cell non-Hodgkin lymphomas are the most common types of lymphoma, in particular follicular lymphoma, (an indolent lymphoma) and diffuse large B-cell lymphoma, an aggressive lymphoma.

Frequencies of  the more common subtypes of non-Hodgkin lymphoma:

Hodgkin Lymphoma

Hodgkin lymphoma, although, less common than other lymphomas, has its own unique aspects.  Typical presentations are enlarged lymph nodes in the neck or within the chest. About 20% of patients also have fevers, sweats or skin itch at the time of diagnosis.

The requirement to biopsy the enlarged nodes and perform CT scans and bone marrow biopsies, in some cases, is similar to other lymphomas.

Hodgkin lymphoma occurs more frequently in younger patients than other lymphomas posing unique issues relating to preservation of fertility and minimizing the long term side effects of treatment.  Fortunately, current treatment using combination chemotherapy and radiotherapy has a high cure rate and fertility is usually preserved. Clinical trials are currently focusing on minimizing treatment in good risk disease and intensifying treatment in poor risk disease. Patients with recurrent disease may still be cured with an autologous stem cell transplant.

More information

For more information about the different subtypes of lymphoma, including patient information booklets, please click here.