What is Extranodal NK-Cell Lymphoma?
Extranodal NK/T-cell lymphoma, nasal type, is an uncommon type of non-Hodgkin
lymphoma (a type of cancer that originates in the lymphatic system). It is always associated with the Epstein-Barr virus
(EBV), a common virus that can trigger certain types of conditions and cancers. This type of lymphoma often results in significant changes to a person’s appearance. Thankfully, with the development of modern treatments, the outlook for those suffering from this disease has improved considerably. However, it’s important to know that life expectancy still heavily depends on the specific type of disease and how early it was diagnosed.
What Causes Extranodal NK-Cell Lymphoma?
Regardless of a patient’s cultural or ethnic background, nearly all cases of a type of lymphoma called extranodal NK/T-cell lymphoma are linked to an infection with the Epstein-Barr virus (EBV). Lymphoma is a type of cancer that affects the immune system. The Epstein-Barr Virus is best known for causing mononucleosis, also known as the “kissing disease.” This strong link suggests that the virus may play a significant role in causing this disease.
Risk Factors and Frequency for Extranodal NK-Cell Lymphoma
Extranodal NK/T-cell lymphoma, a less common type of non-Hodgkin lymphoma, tends to occur more frequently in Asian countries compared to Europe and the United States. It usually affects adults and is more often seen in men than women.
Signs and Symptoms of Extranodal NK-Cell Lymphoma
Extranodal NK/T-cell lymphoma, often found in the nasal area, is a type of cancer that mainly affects the upper part of the digestive and respiratory tracts. People with this condition typically experience symptoms like a nasal mass, nasal blockage, or nosebleeds. Other possible symptoms may include voice changes, difficulty swallowing, bad breath, airway blockage, and vocal cord problems. It’s worth noting that the bone marrow is usually not affected during the initial stages of this disease.
There are also cases where the disease affects other parts of the body, such as the skin, testicles, and gastrointestinal tract. People with gastrointestinal involvement usually suffer from abdominal pain, gastrointestinal bleeding, and even bowel perforation.
Testing for Extranodal NK-Cell Lymphoma
To accurately diagnose your condition, your doctor may need to perform a biopsy, which involves taking a small sample of tissue for testing. This is then examined under a microscope to reveal more about the disease. A special type of screening called immunohistochemical examination is also used, which uses antibodies to help visualise specific proteins in a tissue sample.
Once a diagnosis has been made, your doctor needs to determine how far the disease has spread. This is called staging. To do this, they may use a combined positron emission tomography (PET) and computed tomography (CT) scan. In some cases, the doctor might use contrast-enhanced CT scans or magnetic resonance imaging (MRI) scans. These tests use a special dye to help the organs or tissues show up more clearly in the images.
The doctors interpret the results of your PET/CT scan based on the 2014 Lugano classification. This classification has four stages:
- Stage I: You have the disease in one lymph node, a group of neighbouring lymph nodes, or in one area outside of the lymph nodes.
- Stage II: The disease appears in two or more lymph node groups on the same side of your body or in one area outside of the lymph nodes.
- Stage II bulky: This is similar to stage II but includes a large lump or mass of 10 centimeters or larger, or a mass that takes up more than a third of the space within your chest.
- Stage III: Diseases exists in nodes on both sides of your body or nodes above the area of your diaphragm with spleen involvement.
- Stage IV: There is spread to other organs or tissues that are not near the original lymph node site.
To figure out the severity of extranodal NK/T-cell lymphoma, doctors commonly use a guide known as the Prognostic Index of Natural Killer Lymphoma (PINK). It takes into consideration factors like patient’s age (if over 60), the stage of the disease (III to IV), presence of disease in distant lymph nodes, and presence of non-nasal disease.
Another version of this guide, called PINK-E, also takes into account the amount of Epstein-Barr virus DNA present in the blood at the time of diagnosis. This is tested using a technique called quantitative PCR, which is a way to measure the amount of a specific DNA in a sample. This test has been shown to correlate well with disease stage, response to treatment, and overall outcome, making it an important tool for both diagnosing and monitoring the disease.
Treatment Options for Extranodal NK-Cell Lymphoma
When treating extranodal NK/T-cell lymphoma, a type of cancer primarily affecting the natural killer cells (NK cells) of the immune system, doctors consider several factors. These include the patient’s age, how far the disease has spread, potential side effects, and the patient’s overall health and ability to cope with treatment.
1. Initial Treatment
For patients with lymphoma confined to the nasal area and hasn’t spread (stage I-II), several options exist. Common approaches combine chemotherapy, which is medication to destroy cancer cells, and radiation therapy, which uses high-energy particles to kill cancer cells. An alternative option is a sequence of chemotherapy and radiation therapy, while a sandwich treatment plan refers to alternating periods of chemotherapy and radiation therapy. One can choose any of these combinations depending on the specific case and the patient’s ability to tolerate treatment. For patients who can’t handle chemotherapy, doctors may use radiation therapy alone.
For patients with disease in the nasal area that’s extensively spread (stage IV) or disease outside the nasal area (stage I- IV), treatment options may involve chemotherapy combinations, potentially accompanied by radiation therapy.
2. Assessing the Response to Treatment
After the initial treatment, doctors assess the patient’s response using several methods. A PET/CT scan provides detailed images of the body, and an ear, nose, and throat examination checks for physical signs of the disease. An Epstein-Barr virus (EBV) viral load test looks for levels of the EBV virus, which is often associated with this type of lymphoma. The Deauville criteria, a scoring system, is used to interpret the results of the PET/CT scans.
Based on the assessment, different paths can be followed. For patients with less advanced nasal disease (stage I-II) who’ve had a complete disappearance of all signs of disease after treatment, no further treatment may be needed. If there has been partial reduction but not complete disappearance of disease, a biopsy, or tissue sample, must be taken for further examination. Based on biopsy results, the disease might be deemed refractory, meaning it’s not responding to treatment and additional treatment may be necessary.
In cases of more advanced nasal disease (stage IV) or disease outside the nasal area (stages I-IV), a procedure like a hematopoietic stem cell transplant, where damaged blood cells are replaced with healthy ones, might be considered if the patient has either completely or partially responded to treatment. But as with less advanced disease, a positive biopsy result will lead to additional treatment.
3. For Relapsed or Refractory Disease
Relapsed or refractory disease is when the lymphoma either returns after treatment or doesn’t respond to treatment respectively. This must be confirmed with a biopsy. Treatment options in these cases could be additional rounds of chemotherapy and possibly newer therapies such as Pembrolizumab, an immunotherapy drug that helps the immune system fight cancer. If standard treatments are not suitable, supportive care to manage symptoms or participation in a clinical trial to try new treatments might be suggested.
What else can Extranodal NK-Cell Lymphoma be?
There are certain conditions that can appear similar to extranodal NK/T-cell lymphoma. These include aggressive NK-cell leukemia, nasopharyngeal carcinoma, and other mature T- and NK-cell neoplasms. Therefore, it’s important to take a proper biopsy for examination. This is so that with the help of histopathology (study of the microscopic structure of tissue) and immunohistochemistry (study of the distribution of cellular constituents by means of antibodies), an accurate diagnosis can be determined.
What to expect with Extranodal NK-Cell Lymphoma
The treatment results for a type of cancer known as extranodal NK/T-cell lymphoma have greatly improved thanks to advances in modern therapies. However, the chances of survival are still strongly influenced by the specific type and stage of the disease at the time of diagnosis.
For patients who have the disease in the nasal area, the five-year survival rate (the chance of living at least five years after diagnosis) is at 54%. However, for those with the disease outside the nasal area (extranasal), the five-year survival rate drops to 34%.
Possible Complications When Diagnosed with Extranodal NK-Cell Lymphoma
The primary cause of death in patients with extranodal NK/T-cell lymphoma tends to be non-Hodgkin lymphoma. This is usually followed by other serious cancers, heart disease, and infections. However, there are rare instances where patients exhibit a condition known as hemophagocytic syndrome.
Hemophagocytic syndrome is unusual and extremely dangerous. It is identified through symptoms such as high fever, a significant reduction in the number of different types of blood cells (pancytopenia), enlargement of the liver and spleen (hepatosplenomegaly), liver dysfunction, blood clotting disorders (coagulopathy), increased ferritin levels in the blood (hyperferritinemia), and the abnormal consumption of blood cells by macrophages (hemophagocytosis) in the bone marrow or other organs.
Most Common Causes of Death:
- Non-Hodgkin lymphoma
- Other malignant cancers
- Heart disease
- Infections
Rare Condition Occasionally Presented: Hemophagocytic Syndrome, characterized by:
- High fever
- Pancytopenia
- Hepatosplenomegaly
- Liver dysfunction
- Coagulopathy
- Hyperferritinemia
- Hemophagocytosis in bone marrow or other organs
Preventing Extranodal NK-Cell Lymphoma
Being told that you have extranodal NK/T-cell lymphoma (a type of cancer) and going through the treatment for it can bring significant changes to you and your family’s life. These changes can affect you physically, emotionally, spiritually, and even how you interact with others. So every time you visit the clinic, the doctors will also check how you and your family are feeling emotionally, and what social issues might be affecting you.
You and your family should also understand the different treatment options available, like CRT (a type of therapy using radiation) and combination chemotherapy regimens (a treatment that uses a mix of different medicines to kill cancer cells). Understanding the benefits and drawbacks of each treatment, the side effects, steps to manage and lessen those side effects, and your long-term treatment plan will help you make informed decisions for your health.
It’s also crucial to regularly meet with your primary doctor and cancer specialist to check how well the treatment is working and to manage any unwanted effects of the treatment. Regular follow-ups enable the doctor to monitor your progress and adjust your treatment as necessary.
