Definition of Lymphoma

Lymphoma is a type of blood cancer that occurs when lymphocytes, white blood cells that form a part of the immune system and help protect the body from infection and disease, begin behaving abnormally. Abnormal lymphocytes may divide faster than normal cells or they may live longer than they are supposed to. Lymphoma may develop in many parts of the body, including the lymph nodes, spleen, bone marrow, blood or other organs.

Typically, lymphoma presents as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage of the disease. These malignant cells often originate in lymph nodes, presenting as an enlargement of the node (a tumor). It can also affect other organs in which case it is referred to as extranodal lymphoma. Extranodal sites include the skin, brain, bowels and bone. Lymphomas are closely related to lymphoid leukemias, which also originate in lymphocytes but typically involve only circulating blood and the bone marrow (where blood cells are generated in a process termed haematopoesis) and do not usually form static tumors. There are many types of lymphomas, and in turn, lymphomas are a part of the broad group of diseases called hematological neoplasms.

Cause of  Lymphoma

The causes of lymphoma have not yet been established the scientists have identified several potential risk factors. 

Exposure to certain viruses and bacteria like HIV, human T-lymphocytic virus type 1 (HTLV-1), Epstein-Barr virus, Helicobacter pylori, or hepatitis B or C is associated with lymphoma. For example, Epstein-Barr virus may increase the risk of getting lymphoma and people who are HIV positive have an increased risk of lymphoma.

Genetic and environmental factors, such as exposure to pesticides, carcinogens have also been implicated.

Signs and Symptoms of Lymphoma

Lymphoma presents with certain non-specific symptoms. If symptoms are persistent, lymphoma needs to be excluded medically.

Lymphadenopathy or Swelling of lymph nodes
– It is the primary presentation in Lymphoma.
B symptoms
– Can be associated with both Hodgkin’s lymphoma and non-Hodgkin’s lymphoma. It consists of:

  • Fever
  • Night sweats
  • Weight loss

Other Symptoms :

  • Loss of appetite or Anorexia
  • Fatigue
  • Respiratory distress or Dyspnoea
  • Itching

Risk Factors for Lymphoma

Age. Lymphoma can develop in both children and adults, but the majority of people diagnosed are usually are over the age of 60 because as we age, the risk of NHL increases. HL is most common between ages 16-34 and 55 years and older. Many cases where children have developed the disease is when they have a pre-existing immune system deficiency.

Weak immune system. Other illnesses or diseases, such as HIV/AIDS autoimmune disease (such as lupus); diseases that require therapies that suppress the immune system weaken the immune system and can make the body more susceptible to lymphoma.

Family history. There is no known evidence that lymphoma is hereditary, while some patients with lymphoma claim to have family members also afflicted with the disease. Born with certain genetic mutations or a fault in a gene may make one statistically more likely to develop cancer later in life. 

Infections Illnesses, such as HIV/AIDS, Epstein-Barr virus, human T-lymphocytic virus type 1 (HTLV-1), Hepatitis B or C, and Helicobacter pylori are all factors that can increase the risk of developing lymphoma.

Radiation. Exposure to high levels of radiation such as survivors of nuclear reactor accidents and Atomic bombs is a risk for developing non-Hodgkin’s lymphoma. People also who had previous radiation therapy are also at a higher risk for lymphoma.

Also, high fetal growth, being male, low birth order, and older maternal age can be risk factors.

Diagnosis of Lymphoma

Lymphoma is definitively diagnosed by a lymph node biopsy, meaning a partial or total excision of a lymph node that is then examined under the microscope. This examination reveals histopathological features that may indicate lymphoma. After lymphoma is diagnosed, a variety of tests may be carried out to look for specific features characteristic of different types of lymphoma. These include:

  • Immunophenotyping
  • Flow cytometry
  • FISH testing.

Several classification systems have existed for lymphoma. These systems use histological findings and other findings to divide lymphoma into different categories. The classification of lymphoma can affect treatment and prognosis. Classification systems generally classify lymphoma according to:

  • Whether or not it is a Hodgkin lymphoma.
  • Whether the cell that is replicating is a T cell or B cell.
  • The site that the cell arises from.

Hodgkin’s lymphoma

Hodgkin’s lymphoma is one of the most well-known types of lymphoma, and differs from other forms of lymphoma in its prognosis and several pathological characteristics. A division into Hodgkin’s and non-Hodgkin’s lymphomas is used in several formal classification systems. A Hodgkin’s lymphoma is marked by the presence of a type of cell called the Reed-Sternberg cell.

Prevention from Lymphoma

There are no known ways to prevent lymphoma. However, physicians recommend avoiding known risk factors and avoiding viral infections or conditions that suppress the immune system.

Treatment of  Lymphoma

Prognosis and treatment is different for HL and between all the different forms of NHL, and also depends on the grade of tumour, referring to how quickly a cancer replicates. Paradoxically, high-grade lymphomas are more readily treated and have better prognoses. A well-known example of a high-grade tumour is that of Burkitt’s lymphoma, which is a high-grade tumour that has been known to double within days, but is readily treated.

Low-grade lymphomas

Many low-grade lymphomas remain indolent for many years. In these lymphomas, metastases are very likely. For this reason, treatment of the non-symptomatic patient is often avoided. In these forms of lymphoma, watchful waiting is often the initial course of action. This is carried out because the harms and risks of treatment outweigh the benefits. If a low-grade lymphoma is becoming symptomatic, radiotherapy or chemotherapy are the treatments of choice; although they do not cure the lymphoma, they can alleviate the symptoms, particularly painful lymphadenopathy. Patients with these types of lymphoma can live near-normal lifespans, but the disease is incurable.

High-grade lymphomas

Treatment of some other, more aggressive, forms of lymphoma can result in a cure in the majority of cases, but the prognosis for patients with a poor response to therapy is worse. Treatment for these types of lymphoma typically consists of aggressive chemotherapy, including the CHOP or R-CHOP regimen.

Hodgkin lymphoma typically is treated with radiotherapy alone, as long as it is localized. Advanced Hodgkin disease requires systemic chemotherapy, sometimes combined with radiotherapy. Chemotherapy used includes the ABVD regimen.