Diffuse large B-cell lymphoma stage IV represents the most advanced form of this fast-growing blood cancer, yet despite its aggressive nature, many people respond well to treatment and can achieve remission.
Understanding Diffuse Large B-Cell Lymphoma Stage IV
Diffuse large B-cell lymphoma, often shortened to DLBCL, is a type of blood cancer that develops when certain white blood cells called B cells begin to grow abnormally. These B cells are part of your lymphatic system, which is a network of vessels, tissues, and organs that help your body fight infections and maintain fluid balance. When you have DLBCL, the abnormal B cells are larger than normal healthy ones and spread throughout the lymph nodes or other organs in a scattered pattern rather than in clusters.[1]
At stage IV, DLBCL has reached its most advanced state. This means the cancer has spread beyond the lymphatic system to at least one other organ in your body, such as your liver, lungs, bone marrow, brain, gastrointestinal tract, or other tissues. This makes the cancer metastatic, meaning it has traveled from its original location to distant parts of your body.[2][6]
The name “diffuse large B-cell lymphoma” describes three key features of this cancer. “Diffuse” means the cancer cells are spread out rather than grouped together. “Large B-cell” refers to the fact that these cancerous cells appear unusually large when examined under a microscope. “Lymphoma” indicates that this is a cancer of the lymphatic system.[1]
Epidemiology
Diffuse large B-cell lymphoma is the most common type of non-Hodgkin lymphoma, a group of blood cancers that do not contain specific cells called Hodgkin cells or Reed-Sternberg cells. DLBCL accounts for approximately 25% of all non-Hodgkin lymphomas and makes up more than 40% of NHL cases in adults.[6][7]
Although DLBCL is the most common form of lymphoma, it remains relatively uncommon compared to other cancers. According to data from the National Cancer Institute, in 2020, about 6 people in 100,000 received a DLBCL diagnosis. To put this in perspective, about 500 people in 100,000 received a diagnosis of cancer affecting any part of their bodies during the same period.[3]
DLBCL affects both men and women, but it is more common in males than females. Each year, about 5,000 people are diagnosed with DLBCL in the United Kingdom alone, highlighting that while it is the most frequent type of aggressive lymphoma, it still affects a relatively small portion of the population.[7]
Causes
Diffuse large B-cell lymphoma happens when B cells undergo changes or mutations in their genetic material. These are what doctors call acquired genetic mutations, meaning you develop them during your lifetime rather than being born with them. The exact reason why these mutations occur is not fully understood, but they cause the B cells to grow and multiply uncontrollably.[3]
When these abnormal B cells develop, they lose their ability to function properly. Normal B cells are an essential part of your immune system’s infection-fighting network, but cancerous B cells cannot fight off invaders like viruses and bacteria. Instead, they crowd out healthy cells and spread to various parts of the body.[3]
The World Health Organization has identified more than a dozen different types of DLBCL, each with unique genetic characteristics. These genetic changes in the lymphoma cells are the most important factor in determining how the cancer will likely progress and respond to treatment. Some types of DLBCL are associated with specific viruses, such as the Epstein-Barr virus, which can influence the development of the disease.[3]
Risk Factors
While the exact cause of DLBCL mutations remains unclear, certain factors may increase the risk of developing this type of lymphoma. Blood tests can reveal the presence of certain viruses that may be associated with increased risk. Tests for viruses including Epstein-Barr virus, HIV, hepatitis B, and hepatitis C are often performed as part of the diagnostic process to understand whether viral infections might be contributing factors.[4]
The different subtypes of DLBCL can be classified based on their cell of origin. Two main types are germinal center B-cell-like (GCB) and activated B-cell-like (ABC). GCB originates in B cells that are undergoing specialization in the germinal center of the lymph node, while ABC originates in B cells that have already been activated by antigens but are not fully matured. These subtypes respond differently to treatment and have different outlooks.[6]
Some genetic subtypes include what doctors call “double-hit lymphoma” or “triple-hit lymphoma.” These forms of DLBCL are linked to genetic variants of specific genes like MYC, BCL2, and BCL6. These genetic characteristics can affect how aggressive the cancer is and how it responds to treatment.[6]
Symptoms
The symptoms of diffuse large B-cell lymphoma can develop or worsen quickly, sometimes within just a few weeks. This rapid onset is due to the aggressive, fast-growing nature of this type of lymphoma. The most common symptom that people notice is one or more painless swellings in specific areas of their body.[7]
These swellings are enlarged lymph nodes, and they typically appear in the neck, armpits, or groin. They feel like lumps under the skin that don’t go away and may seem to be getting larger over time. While these lumps are usually painless, in some cases they can cause discomfort or pain. The lumps can grow very quickly, which is characteristic of high-grade or fast-growing lymphomas.[3][7]
About 30% of people with DLBCL experience what doctors call “B symptoms.” These include a fever above 103 degrees Fahrenheit (39.5 degrees Celsius) that lasts longer than two days or comes and goes without an obvious cause. Another B symptom is unexplained weight loss, specifically losing more than 10% of your total body weight over a period of six months without trying to lose weight. The third main B symptom is heavy night sweats that are so intense they drench your sheets.[3][7]
Some people may also experience unexplained itching of the skin, even without any visible rash or irritation. Because DLBCL can develop outside the lymph nodes in various organs, the symptoms you experience can depend on where the cancer is growing in your body.[7]
If DLBCL is affecting your abdomen or bowel, you might experience pain, diarrhea, or bleeding. When it grows in your chest, you might feel breathless or develop a persistent cough. Other symptoms might include debilitating fatigue and flu-like symptoms without an actual fever, as experienced by some patients.[7][16]
Prevention
Because the exact causes of diffuse large B-cell lymphoma are not fully understood, there are no specific prevention strategies that can guarantee you will not develop this disease. The genetic mutations that lead to DLBCL occur during a person’s lifetime, and scientists do not yet know exactly what triggers these changes in the B cells.
However, understanding potential risk factors associated with viral infections may be helpful. Blood tests can check for viruses such as Epstein-Barr virus, HIV, hepatitis B, and hepatitis C, which have been associated with certain types of DLBCL. Managing or preventing these viral infections through vaccination or other medical interventions, where possible, may be beneficial for overall health.[4]
Since DLBCL is a fast-growing cancer, early detection is crucial. Being aware of the symptoms and seeking medical attention promptly when you notice unusual changes in your body can lead to earlier diagnosis and treatment, which generally improves outcomes. Regular health check-ups and being attentive to persistent symptoms like unexplained lumps, fevers, weight loss, or night sweats can help catch the disease in its earlier stages.[3]
Pathophysiology
The pathophysiology of diffuse large B-cell lymphoma involves significant changes in how your body’s normal systems function. Your lymphatic system, which includes lymph nodes, vessels, and organs, plays a crucial role in immune function. It contains a straw-colored liquid called lymph that circulates around your body tissues, carrying a high number of white blood cells called lymphocytes that fight infection.[7]
In DLBCL, the body starts making abnormal B lymphocytes instead of normal ones. These abnormal cells are significantly larger than healthy B cells and have undergone genetic mutations that cause them to grow and multiply uncontrollably. When examined under a microscope, these cancerous cells appear noticeably larger than their normal counterparts, which is why the term “large B-cell” is used in the disease name.[1]
The abnormal lymphocytes build up in the lymph nodes or other body organs in a diffuse or scattered pattern. Unlike some other types of lymphoma where cancer cells cluster together, in DLBCL the cells are spread throughout the affected tissue. These cancer cells don’t function properly, meaning they cannot fight infection as normal white blood cells do. Instead, they crowd out healthy cells and interfere with normal organ function.[7]
In stage IV DLBCL, the cancer has spread beyond the lymphatic system to at least one other organ outside of it. The cancerous B cells may appear in virtually any organ, including the gastrointestinal tract, thyroid, skin, breast, bone, or brain. When the cancer spreads to the bone marrow, it can interfere with the production of normal blood cells, potentially causing problems like anemia, increased risk of infection, or bleeding issues.[3]
Blood tests often reveal elevated levels of lactate dehydrogenase (LDH), which is a substance that is frequently higher in people with lymphoma. This marker helps doctors assess the extent and activity of the disease. The rapid growth characteristic of DLBCL means that symptoms can develop or worsen within weeks, making it a high-grade or aggressive form of lymphoma.[4][7]
Gene expression profiling has identified distinct forms of DLBCL based on molecular characteristics. The activated B-cell-like (ABC) type and germinal center B-cell-like (GCB) type have different oncogenic mechanisms and respond differently to treatment. Next-generation sequencing has revealed unique genetic complexities that provide valuable information about therapeutic targets and how the disease might progress.[10]
