Diffuse large B-cell lymphoma – Diagnostics – Overview of Information and Clinical Research

Diagnosing diffuse large B-cell lymphoma involves a careful combination of physical examination, blood tests, imaging studies, and tissue analysis. Understanding these diagnostic steps can help patients know what to expect when their doctor suspects this fast-growing but often treatable type of lymphoma.

Introduction: When to Seek Diagnostics

If you notice a painless lump in your neck, armpit, or groin that doesn’t go away and seems to be growing larger, it’s important to see a healthcare provider. These swollen lymph nodes are the most common sign that something might be wrong. About 30% of people with diffuse large B-cell lymphoma also experience what doctors call “B symptoms” – a combination of unexplained fever above 103 degrees Fahrenheit, unintended weight loss of more than 10% of your body weight over six months, and heavy night sweats that drench your sheets.^[2]^[7]

Because this type of lymphoma grows quickly, symptoms can appear or worsen in just a few weeks. Some people experience breathlessness, persistent cough, or low-level flu-like symptoms that never really go away. Others might notice swelling in their face, neck, or upper body, or develop a mass in areas like the abdomen or chest.^[2]^[19] The disease can affect not just lymph nodes but virtually any organ in the body, including the gastrointestinal tract, skin, bones, or brain.^[1]

You should contact a healthcare provider anytime you notice changes in your body that last for several weeks. While these symptoms don’t necessarily mean you have lymphoma, early diagnosis and prompt treatment improve outcomes significantly. Because diffuse large B-cell lymphoma is aggressive but often curable, getting diagnosed early matters.^[7]

⚠️ Important

Having swollen lymph nodes or B symptoms doesn’t automatically mean you have diffuse large B-cell lymphoma. Many other conditions can cause similar symptoms. However, any lump that doesn’t go away and seems to be getting larger, especially when combined with fever, weight loss, or night sweats, deserves medical attention. Early evaluation allows for prompt diagnosis and treatment if lymphoma is present.

Classic Diagnostic Methods

Physical Examination

The diagnostic process typically begins with a thorough physical exam. Your doctor will check for swollen lymph nodes in your neck, underarms, and groin by carefully feeling these areas. They will also examine your abdomen to see if your spleen or liver is enlarged, which can happen when lymphoma spreads to these organs. This hands-on examination helps your doctor understand where the disease might be located and how extensive it appears to be.^[10]

Blood Tests

Blood tests play an important role in diagnosing diffuse large B-cell lymphoma, even though the disease doesn’t always show up directly in blood samples. These tests can sometimes reveal the presence of lymphoma cells. More commonly, they measure levels of a substance called lactate dehydrogenase, or LDH, which is often higher in people with lymphoma. Elevated LDH levels can indicate more aggressive disease.^[10]

Your doctor will also order blood tests to check for certain viruses that can be associated with lymphoma. These include Epstein-Barr virus (which some people know as the virus that causes infectious mononucleosis), HIV, hepatitis B, and hepatitis C. Understanding whether you have any of these infections helps doctors determine your specific type of lymphoma and plan appropriate treatment.^[10]

Imaging Tests

Imaging tests create detailed pictures of the inside of your body, allowing doctors to see the location and size of lymphoma. The most commonly used imaging test for diffuse large B-cell lymphoma is called a PET-CT scan. This combines two types of scans: a PET scan, which shows metabolic activity in tissues, and a CT scan, which creates detailed cross-sectional images. Together, they help doctors identify all areas where lymphoma is present throughout your body.^[10]^[5]

Other imaging tests might include MRI scans, which are particularly useful for looking at the brain or spine, or regular CT scans of the chest, abdomen, or pelvis. These tests help doctors understand how far the lymphoma has spread, which is essential for planning treatment.^[10]

Lymph Node Biopsy

The definitive test for diagnosing diffuse large B-cell lymphoma is a biopsy. During this procedure, a doctor removes all or part of a swollen lymph node, or takes a sample from another affected area of the body. This tissue sample is then sent to a laboratory where a specialist called a hematopathologist examines it under a microscope.^[5]^[8]

Looking at the cells under a microscope, the pathologist can see that the cancer cells are larger than normal, healthy B cells. The cancer cells also appear spread out, or diffuse, rather than grouped together in a pattern. This is how diffuse large B-cell lymphoma gets its name. The biopsy also helps determine the specific subtype of lymphoma you have, as there are more than a dozen different types of diffuse large B-cell lymphoma, each with unique characteristics.^[1]^[2]

In some cases, if lymphoma is suspected in organs other than lymph nodes, a biopsy may be taken from those locations. This could include tissue from the gastrointestinal tract, skin, bone, or other organs depending on where symptoms appear.^[3]

Bone Marrow Testing

To check whether lymphoma has spread to your bone marrow (the soft, spongy tissue inside your bones where blood cells are made), your doctor may recommend a bone marrow aspiration and biopsy. This procedure involves using a needle to collect both liquid and solid samples from your bone marrow, typically from your hip bone. These samples are examined in a laboratory to look for lymphoma cells.^[10]

Understanding whether lymphoma has reached your bone marrow helps doctors determine the stage of your disease and plan the most effective treatment approach. This information is particularly important because it affects your prognosis and may influence treatment decisions.

Lumbar Puncture

In certain situations, especially if there’s concern that lymphoma might have spread to the brain or spinal cord, your doctor may recommend a lumbar puncture (also called a spinal tap). During this procedure, a small amount of fluid is removed from around your spine and tested for the presence of lymphoma cells. This test is particularly important for people with specific subtypes of diffuse large B-cell lymphoma or those with certain risk factors for central nervous system involvement.^[5]

Staging and Prognostic Tools

Once lymphoma is confirmed, doctors use a system called the International Prognostic Index, or IPI, to help predict how the disease might respond to treatment and whether it’s likely to come back after treatment. The IPI considers five factors: your age (whether you’re 60 or older), your LDH level, the stage of your disease (whether it’s stage 3 or 4), your overall physical condition (called performance status), and whether lymphoma is present in more than one area outside the lymph nodes.^[16]

Based on how many of these risk factors you have, you’re assigned to a risk group: low risk (0 or 1 factor), low-intermediate risk (2 factors), high-intermediate risk (3 factors), or high risk (4 or 5 factors). This classification helps your healthcare team make treatment decisions that are right for you and helps you understand what to expect from your treatment.^[16]

⚠️ Important

If you’ve been diagnosed with diffuse large B-cell lymphoma that has relapsed (come back) or is being evaluated for a change in treatment, your doctor may recommend a repeat biopsy. This is because the characteristics of lymphoma cells can sometimes change over time, and checking for continued expression of certain proteins like CD19 or CD20 helps ensure you receive the most appropriate treatment for your current condition.

Diagnostics for Clinical Trial Qualification

Molecular and Genetic Testing

When considering enrollment in clinical trials, additional specialized testing may be performed on biopsy samples. These tests look at specific genetic changes and characteristics of the lymphoma cells. For example, doctors may test to determine whether your lymphoma is the germinal center B-cell subtype or the activated B-cell subtype. These distinctions are increasingly important because they help predict how the disease might respond to certain treatments, particularly newer targeted therapies being studied in clinical trials.^[2]^[9]

More than 70 different genetic mutations have been linked to diffuse large B-cell lymphoma. Understanding which genetic changes are present in your specific case can help match you with clinical trials testing treatments designed to target those particular abnormalities.^[7]

Immunophenotyping

Clinical trials often require confirmation that your lymphoma cells express certain surface proteins. Tests called immunophenotyping identify which proteins are present on the surface of your lymphoma cells. This is particularly important because many newer treatments, including targeted antibodies and CAR T-cell therapies, work by recognizing and attaching to specific proteins like CD19 or CD20 on the surface of cancer cells.^[12]

If a clinical trial involves a treatment that targets CD19, for example, your lymphoma cells must be CD19-positive for you to be eligible. Similarly, treatments targeting CD20 require CD20 expression on the cancer cells. These tests are performed on biopsy tissue and help ensure that you’re matched with trials where you’re most likely to benefit.^[12]

Baseline Imaging and Functional Assessment

Before enrolling in a clinical trial, you’ll typically undergo comprehensive baseline imaging, usually including a PET-CT scan. This creates a detailed map of where lymphoma is present in your body at the start of the trial. These images serve as a reference point for measuring how well the experimental treatment works. Additional scans performed during and after treatment are compared to these baseline images to determine if the lymphoma is shrinking, staying stable, or growing.^[11]

Clinical trials also assess your overall physical condition using what’s called a performance status score. This score reflects how well you’re able to carry out daily activities and how the disease is affecting your life. Trials often have specific requirements about performance status to ensure participants are well enough to receive the treatment being studied.

Additional Blood Work

Clinical trials typically require more extensive blood testing than standard care. Beyond the routine blood counts and chemistry panels, you might need tests that measure your immune system function, liver and kidney function, and specific biomarkers that might predict how you’ll respond to treatment. Some trials require testing for specific viral infections beyond what’s done in standard diagnosis, as certain experimental treatments can affect how your body controls viruses.^[10]

Cardiac and Organ Function Tests

Many clinical trials require tests to ensure your heart, lungs, liver, and kidneys are functioning well enough to handle the experimental treatment. These might include an echocardiogram or EKG to check your heart function, pulmonary function tests to assess your breathing, and detailed blood tests to evaluate liver and kidney performance. These baseline measurements help protect your safety during the trial and ensure you’re a good candidate for the specific treatment being studied.

Documentation of Prior Treatments

For trials involving relapsed or refractory diffuse large B-cell lymphoma (disease that has come back or didn’t respond to initial treatment), detailed records of all previous treatments are required. This includes documentation of which chemotherapy regimens you received, how many cycles you completed, how your disease responded, and how long any remissions lasted. This information helps determine whether you meet the trial’s eligibility criteria and helps researchers understand the context of your disease history.^[15]

Prognosis and Survival Rate

Prognosis

The outlook for people with diffuse large B-cell lymphoma varies considerably depending on several factors, but many patients can be cured with treatment. About 75% of patients who receive initial treatment respond well to standard chemotherapy-based therapy, and a significant number of people are cured of the condition. The aggressive nature of this lymphoma actually works in patients’ favor in some ways, as fast-growing cancers often respond better to chemotherapy than slow-growing ones.^[7]

The International Prognostic Index helps predict outcomes based on risk factors. Patients with low-risk disease generally have better outcomes than those with high-risk disease. Factors that affect prognosis include age (being 60 or older is associated with worse outcomes), disease stage, LDH levels, performance status, and whether lymphoma has spread to multiple sites outside the lymph nodes. Early-stage disease caught and treated promptly generally has a more favorable prognosis than advanced-stage disease.^[16]

Between 50% and 60% of all patients are cured with rituximab-based chemotherapy in the first-line setting. Treatment causes substantial morbidity due to both acute and long-term side effects, and treatment-related mortality ranges between 2% and 8%. For patients whose disease relapses or doesn’t respond to initial treatment, newer therapies including CAR T-cell therapy, bispecific antibodies, and antibody drug conjugates offer additional chances for response and potential cure.^[11]^[12]

Survival rate

In studies of patients receiving the standard R-CHOP regimen (rituximab combined with chemotherapy), those who received this combination treatment spent an average of 2.9 years without their cancer advancing or requiring a change in therapy, compared with an average of 1.1 years for patients who received chemotherapy without rituximab. Adding rituximab to chemotherapy reduced the risk of death by 32% compared to chemotherapy alone.^[14]

For patients with relapsed disease, CAR T-cell therapy offers another opportunity for cure, with roughly 30% to 40% of patients having the potential to achieve long-term remission or cure. The specific survival rates vary depending on the risk group at diagnosis, with low-risk patients having significantly better survival than high-risk patients. Relapsed or refractory disease typically occurs within the first two years after diagnosis for those who don’t achieve durable remission with initial treatment.^[11]^[12]