Definition and Overview

Lymphoma is cancer that starts in lymphocytes, one of the several types of white blood cells (WBC). Lymphocytes are an integral part of the immune system, which helps fight antigens that enter the body.

Lymphomas are either Hodgkin’s or non-Hodgkin’s. The former is responsible for about 10% of all lymphoma cases while the latter accounts for the remaining 90%. If cancer cells contain abnormal cells called Reed-Sternberg cells, the condition is classified as Hodgkin’s. Otherwise, it is classified as non-Hodgkin’s.

Non-Hodgkin’s lymphoma (NHL) can develop in B cells (B cell non-Hodgkin's lymphoma) or T cells. B cells or B lymphocytes make antibodies that circulate and bind to antigens to help the immune system easily identify them. T lymphocytes (T cells), on the other hand, are responsible for cell-mediated immunity. They are divided into subsets based on their function such as cytotoxic, suppressor, and helper.

According to data gathered between 2007 and 2011, there are about 20 cases of NHL per 100,000 adults in the United States. In 2015, there were approximately 4.3 million people suffering from the condition and more than 230,000 individuals that died from it. These make NHL one of the most common cancers and the 11th most common cause of cancer death.

Causes of Condition

To understand how NHL occurs, it helps to know more about the body’s lymphatic system. It is a part of the immune system that is responsible for protecting the body against illnesses. Lymph tissue is found in different parts of the body including the spleen, lymph nodes, adenoids, bone marrow, tonsils, and digestive tract. NHL occurs when old lymphocytes do not go through their normal life cycle. Instead of dying and being replaced by new cells, they continue to grow and divide, causing the lymph nodes to swell. Although the exact reasons why cells behave abnormally are not yet fully understood, the development of NHL is associated with the following:

  • Autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis

  • Genetic diseases such as ataxia telangiectasia and Klinefelter's syndromes

  • HIV/AIDS

  • Infectious agents such as human T-cell leukemia and Epstein-Barr viruses

  • Treatment for another type of cancer including chemotherapy and radiation therapy

  • Immunosuppressant therapy, which compromises the body’s ability to fight off new diseases

  • Exposure to certain chemicals

  • Old age – Although NHL can occur at any age, it is most commonly diagnosed in people in their 60s.

Key Symptoms

Non-Hodgkin’s lymphoma symptoms vary depending on the tumour’s size and location. These may include:

  • Breathing problems

  • Chest pain

  • Enlarged or swollen lymph nodes in the groin, armpits or neck

  • Fatigue

  • Fever

  • Lumps and itchiness

  • Night sweats

  • Seizures, weakness, personality changes, and problems with thinking, if cancer develops in the brain

  • Weight loss

The severity of the symptoms of non-Hodgkin's lymphoma depends on how fast the malignant tumour is growing or spreading. Indolent lymphomas, or those that grow and spread slowly, are usually asymptomatic even when the disease is at an advanced stage. Meanwhile, aggressive lymphomas, which tend to grow and spread quickly, produce very noticeable signs that affect patients’ quality of life. For this reason, they must be treated at the soonest possible time.

Who to See and Types of Treatments Available

Non-Hodgkin's lymphoma treatment depends on the severity of the disease and whether it is indolent or aggressive. To fully assess the condition, patients undergo a thorough physical examination as well as blood, urine, and imaging tests, which may include positron emission tomography (PET), computerised tomography (CT), and magnetic resonance imaging (MRI) scans. A biopsy is also commonly performed to determine if the patient has NHL or Hodgkin’s lymphoma. The procedure involves harvesting a lymph node and a sample of bone marrow for testing.

For patients with a slow-growing tumour, a wait-and-see approach is normally recommended by doctors. With this method, patients are scheduled for periodic tests to monitor the tumour and ensure that it is not progressing. Indolent lymphomas do not produce symptoms and in some cases, they regress on their own.

Patients with aggressive NHL or those with non-Hodgkin’s lymphoma stage 4 are subjected to treatment as soon as possible. Standard treatments include chemotherapy (a drug treatment that kills cancer cells) and radiation therapy (uses high-powered energy beams to shrink tumours). These can be combined or performed individually depending on patient-specific circumstances.

Stem cell transplant, which is a common treatment method for blood cancers, is also used for the treatment of NHL. The procedure can be performed either through autologous or allogeneic transplantation. In an autologous transplant, doctors collect the patient’s own stem cells, which are then frozen for later use. Following the completion of a powerful chemotherapy treatment, the frozen stem cells are thawed and returned to the patient’s body through an IV. Once they reach the bone marrow, the stem cells will grow, multiply, and help the marrow make healthy blood cells. Allogeneic transplantation follows the same process except that the stem cells are obtained from a donor.

Patients’ treatment may also include the use of biological therapy drugs that aim to boost the immune system’s ability to fight cancer as well as radioimmunotherapy drugs that deliver radiation directly to cancer cells.

With the development of new therapies and anti-cancer drugs, non-Hodgkin's lymphoma survival rate has greatly improved over the years. According to the American Cancer Society, the 5-year survival rate for NHL patients is 67% while the 10-year survival rate is 55%. Aggressive lymphomas are curable with intensive treatment while those with slow-growing lymphomas usually live for many years without problems.

References:

  • What you need to know about non-Hodgkin lymphoma. National Cancer Institute. http://www.cancer.gov/cancertopics/wyntk/non-hodgkin-lymphoma.

  • What you need to know about Hodgkin lymphoma. National Cancer Institute. http://www.cancer.gov/cancertopics/wyntk/hodgkin.

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