Lymphoma

Lymphoma is a disorder of the lymphatic system. The lymphatic system consists of lymphoid organs and lymphatic vessels and has a pivotal role in the body’s immune system. The lymphoid organs are lymph nodes, spleen, thymus gland, and bone marrow, where the lymphatic system cells are born, grown, and processed. The lymphatic system cells are lymphocytes, also called the white blood cells, which are of two types; T cells and B cells. In lymphoma, there is an abnormal enlargement (tumor) of the lymphoid organs (particularly lymph nodes) with uncontrolled production of lymphocytes. Lymphomas are quite a common type of neoplasms, mostly malignant (cancerous). They are treated with chemotherapy, radiotherapy, immunotherapy and have different survival rates depending on the types and subtypes. 

Although the exact cause of these cancers is still unclear, a combination of genetic and environmental factors that can induce mutations in the genetic constitution of the lymphocytes and their DNA is thought to be responsible for the disease. These mutations bring about uncontrolled divisions and the growth of the ineffective cells replacing the normal cells, ultimately pooling your blood and lymphoid organs with all of the diseased cells. The environmental factors that can trigger the disease may include infections with some agents like the Epstein-Barr virus, HIV, Helicobacter pylori, HCV, HBV, or being immunocompromised either due to congenital or acquired diseases or suffering from chronic illnesses like celiac disease, Sjogren's syndrome, Hashimoto's thyroiditis, etc. 

There are many types and subtypes of lymphoma, but the two main categories are described below;

Hodgkin's lymphoma: This type has a special type of cells called the Reed–Sternberg cell. It makes 15% of the total lymphomas but is less common than non-Hodgkin's lymphoma. It starts by affecting the neck, chest, and armpits lymph nodes and progresses to the other lymph nodes down the body. It has a predictable course and prognosis. This type is almost curable due to recent treatments and ongoing research. It affects two peaks of age groups, one in the 20s and the other above 55. 

Non-Hodgkin's lymphoma: All other types that don’t have the Reed–Sternberg cell fall in Non-Hodgkin’s lymphoma category. They are more common than Hodgkin’s but have a poorer prognosis. The age group for this type is 65 and above.

According to National Cancer Institute, the incidence of Hodgkin's lymphoma is 2.6 cases per 100,000 population during the years 2014-2018 in the USA. It affects two peaks of age groups, one in the 20s and the other above 55. 

Non-Hodgkins lymphoma is 5 times more common than Hodgkin disease. The age group for this type is 65 and above. Lymphomas are more prevalent in males than in females.

Worldwide, there were 566,000 cases of lymphoma in 2012 and 305,000 deaths. Lymphomas are the 7th most common form of cancer globally and the third-most common cancer in children. They are more prevalent in developed countries. 

The following factors increase the chances of getting lymphoma. 

• Infections like EBV, HCV, Helicobacter pylori, HIV aids
• Exposure to pesticides and chemicals
• Being Immunocompromised (Congenital immunodeficiency states (e.g., Wiskott-Aldrich syndrome, severe combined immunodeficiency disease [SCID], induced immunodeficiency states (e.g., immunosuppression), acquired immunodeficiency states (e.g., AIDS), 
• Maternal smoking
• Exposure to chemotherapy and radiations
• Chronic diseases like celiac disease, Sjogren's syndrome, Hashimoto's thyroiditis
• Genetics

If you are having the following symptoms, you might need to consult your doctor immediately;

• Painless, enlarged, palpable lymph nodes, especially at the neck, armpits, chest, groin
• Mild fever
• Night sweats
• Itching
• Unexplained weight loss
• Lesions on the skin
• Fatigue
• Discomfort and enlarged abdomen may point towards an enlarged spleen or liver.

Your doctor will ask you questions regarding your symptoms and will perform a physical examination, especially of the lymph nodes in the regions of the neck, armpits, chest, groin, etc. You may be advised on undergoing the following investigations;

• Blood tests: CBC to get a complete picture of the blood cells, especially the lymphocytes, abnormal liver function tests, LDH, and calcium levels, HIV serology, HBV, HCV testing, etc.
• Biopsy: an enlarged lymph node may be excised and sent to the lab for analysis of the cells and to diagnose the type of cancer.
• Bone marrow sampling: a sample of your bone marrow can be taken to assess the lymphocytes' growth and types in the lab.
• Imaging: a CT scan of the concerned area like chest or neck, etc., or a PET scan can show all the places with possible tumorous lymph nodes. MRI of the spinal cord/ brain can provide details of the tumors in these structures.

Some other disorders that might mimic the presentation of lymphoma are;

• Tuberculosis (TB)
• Sarcoidosis
• Melanoma
• Granulocytic sarcoma
• Toxoplasmosis
• Other Solid tumors
• Metastasis of other cancers in the body to the lymph nodes

Treatment of lymphomas depends on the types and the subtypes, the aggressiveness of the tumor, the symptoms, and patient preferences, but the best treatment modalities are chemotherapy, immunotherapy, radiotherapy, bone marrow transplantation, or surgery for localized disease. 

Some of the medications used in the management of lymphomas are; 

• Cytotoxic agents: cyclophosphamide, Adriamycin, vinblastine, dacarbazine, chlorambucil, bleomycin, doxorubicin, fludarabine, vincristine, etc
• Colony-stimulating factor growth factors: darbepoetin alfa, pegfilgrastim
• Monoclonal antibodies: rituximab, alemtuzumab, obinutuzumab, ofatumumab. 
• kinase inhibitors: temsirolimus
• Proteasome inhibitors: bortezomib
• Immunomodulators: interferon alfa-2a or alfa-2b
• Corticosteroids: prednisone, dexamethasone

Procedures

• bone marrow transplantation 
• Hematopoietic stem cell transplantation
• Surgery for localized diseases like GIT lymphoma

The prognosis depends on the stage of the disease and many other prognostic factors like levels of serum albumin, LDH, Beta2-microglobulin, cell counts, age, tumor grade, histology, etc. The five-year survival rate for Hodgkin’s lymphoma is 86.2% and for NHL is 72.7%. 

The following strategies may help you cope with your illness;

• Try to learn about your disease as much as possible
• Be vigilant with your appointments and medicines
• Be around your friends and family members to feel supported
• Join some support groups with people having the same illness to get encouragement
• Take a healthy balanced diet with all the important nutrients and micronutrients
• Perform regular exercise or walk to keep you healthy and active.