Radiotherapy for Lymphoma: Types, Success Rate, Side Effects And More

Radiation therapy remains one of the most powerful tools in the treatment of both Hodgkin and non-Hodgkin lymphoma. Once delivered with large fields and high doses, modern radiotherapy now uses smaller, highly conformal fields and lower doses guided by CT and PET imaging, substantially reducing long-term toxicity while preserving excellent local control.

In Hodgkin lymphoma, radiation is used selectively as part of combined modality therapy, particularly in early-stage disease, bulky presentations, or partial responses to chemotherapy. In non-Hodgkin lymphoma, it continues to play versatile roles—as definitive treatment in localized indolent disease, as consolidation in aggressive subtypes, and as an effective salvage or palliative option, including in the era of novel agents and cellular therapies such as CAR T-cells. This article reviews contemporary indications, techniques, and evolving applications of radiotherapy across the lymphoma spectrum.

What is Radiotherapy for Lymphoma?

Radiotherapy for lymphoma is a cancer treatment that uses high-energy x-rays (or particles like protons) to kill lymphoma cells in a specific part of the body. It is a local treatment, meaning it targets only the lymph nodes or organs in the radiation field, unlike chemotherapy or immunotherapy, which circulate throughout the body.

For lymphoma, radiotherapy is almost always given as external beam radiation therapy: a machine outside the body directs precisely shaped radiation beams at the areas involved by lymphoma. Modern planning uses CT (and often PET) scans to map out exactly where the lymphoma is and to design fields that treat the disease while protecting nearby organs such as the heart, lungs, thyroid, and bone marrow.

Radiotherapy can be used with different goals:

• Curative/definitive treatment in some early-stage Hodgkin and indolent non-Hodgkin lymphomas
• Consolidation after chemotherapy to reduce the risk of local relapse, especially in bulky or high-risk sites
• Salvage or palliative treatment to control relapsed/refractory disease, relieve symptoms (pain, compression, bleeding), or shrink resistant masses

Because lymphoma cells are highly sensitive to radiation, effective control is often achieved with moderate doses and small treatment fields, which helps limit short- and long-term side effects.

Types of Radiotherapy for Lymphoma

Most people with lymphoma are treated with external beam radiation therapy (EBRT). A machine outside the body directs high-energy x-rays (or sometimes proton beams) to the lymph nodes or organs that contain lymphoma.

Involved-Site Radiation Therapy (ISRT)

Involved-site radiation therapy is the current standard field concept for most Hodgkin and non-Hodgkin lymphomas. With ISRT, radiation is delivered only to the lymph nodes and tissues that were involved at diagnosis, plus a small safety margin. This allows the treatment team to control the disease while limiting radiation exposure to organs such as the heart, lungs, thyroid, breasts, or bowel.

Involved-Field Radiation Therapy (IFRT)

Involved-field radiation therapy was widely used before ISRT became standard. IFRT treats entire lymph node regions, such as the whole mediastinum or neck, rather than just the specific nodes originally involved. Because the treatment area is larger than with ISRT, more surrounding normal organs may receive radiation, which can increase the risk of side effects.

Extended-Field Radiation Therapy (EFRT) ( Historical)

Extended-field techniques, such as the mantle field and inverted Y, were used historically when radiotherapy alone was the main treatment for lymphoma. These fields covered very large nodal areas above and below the diaphragm. They are now rarely used in modern practice because they expose much more normal tissue and are associated with higher rates of late toxicities, including heart disease and second cancers. ISRT has largely replaced EFRT.

Modern Delivery Techniques

Modern radiotherapy techniques describe how the radiation dose is shaped and delivered. Three-dimensional conformal radiation therapy (3D-CRT) uses CT-based planning to design beams that conform to the target in three dimensions. More advanced techniques, such as intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), modulate the intensity and angle of the beams to wrap the dose tightly around the lymphoma while avoiding nearby critical structures. Proton therapy uses proton beams instead of x-rays and can reduce the dose delivered beyond the target, which may be especially useful in selected cases, such as young patients or those with mediastinal disease close to the heart and breasts.

Short-Term Side Effects of Radiotherapy for Lymphoma

Short-term, or acute, side effects of radiotherapy usually develop gradually over the course of treatment and tend to improve within weeks after finishing. They depend mainly on the area being treated and the total dose, but some general patterns are common.

The most frequent short-term side effect is tiredness (fatigue). Many people notice their energy level dropping as treatment goes on, even if they are still sleeping well. Light, regular physical activity—such as walking—often helps reduce this fatigue, so your team will usually encourage you to stay as active as you comfortably can.

Skin changes are also common in the area that receives radiation. The skin may become red, dry, itchy, or slightly tender, similar to a sunburn. In most cases these reactions are mild to moderate and can be managed with gentle skin care and creams recommended by your radiation team. The skin usually heals after treatment ends.

Other side effects depend on the part of the body being treated. For example, radiation to the abdomen can cause nausea, cramping, or diarrhea. Treatment to the neck or chest may cause a sore throat, dry mouth, or mild difficulty swallowing for a period of time. When larger areas are treated, or when radiotherapy is given after chemotherapy, blood counts can sometimes drop, which may temporarily increase the risk of infection or bruising.

These effects often build up toward the end of the course rather than appearing all at once. Most are temporary and improve once radiotherapy is completed. You will have regular reviews with your radiation oncologist and treatment team, who will monitor your symptoms, adjust medications if needed, and support you through side-effect management. It is important to tell them about any new or worsening symptoms so they can help you stay as comfortable and safe as possible during treatment.

Read Our Special Article About Immunotherapy for Lymphoma

Long-Term Side Effects of Radiotherapy for Lymphoma

Some side effects of radiotherapy do not appear until months or even years after treatment finishes. These are called late effects. They are less common with modern, smaller radiation fields and lower doses, but they are still important to understand, especially because many people with lymphoma live for decades after treatment.

Heart and Lung Problems

If radiotherapy includes the chest, it can slightly increase the risk of heart disease (such as coronary artery disease or heart failure) and lung problems (such as scarring or reduced lung capacity). Shortness of breath, chest pain, or reduced exercise tolerance years after treatment should be discussed with your doctor, who can consider whether they might be related to prior therapy.

Second Cancers

There is a small increased risk of developing a second cancer in or near the area that was irradiated, or after some types of chemotherapy. This risk usually appears many years later. Modern techniques that limit dose to normal tissues are designed to keep this risk as low as possible, but it cannot be reduced to zero.

Hormonal and Fertility Effects

Radiation to the neck or upper chest can affect the thyroid gland, sometimes causing it to underperform (hypothyroidism). This can lead to fatigue, weight gain, and feeling cold. It is often easily treated with thyroid hormone tablets, but it requires lifelong monitoring.

Some chemotherapy drugs and pelvic or lower-abdominal radiation can affect the ovaries or testicles, leading to reduced fertility or early menopause in women. These changes may be temporary or permanent. For younger patients, fertility preservation options are often discussed before treatment starts.

Bone Health and Growth

Early menopause, steroid use, and some treatments can increase the risk of osteoporosis, where bones become thinner and more fragile, increasing the chance of fractures. Bone health can be monitored and supported with lifestyle measures and, when needed, medication. In children and adolescents, radiation near growing bones may affect bone growth and final height, so fields and doses are planned very carefully.

Stroke and Vascular Risk

Radiation to the neck can, over many years, increase the risk of narrowing of the carotid arteries, which may contribute to stroke risk later in life. This is another reason long-term follow-up and good control of blood pressure, cholesterol, and smoking status are important.

How Many Radiotherapy Sessions for Lymphoma?

The number of radiotherapy sessions for lymphoma varies and is tailored to each patient. A single visit to the machine is called a session or fraction, and treatments are usually given once a day, Monday to Friday.

For most people having radiotherapy with curative or consolidation intent, such as after chemotherapy for Hodgkin or aggressive non-Hodgkin lymphoma, treatment typically runs over about 2 to 4 weeks. This usually means around 10 to 20 sessions in total. For localized indolent lymphomas treated with standard doses (for example, 24–30 Gy), the course is often around 2 to 3 weeks, which corresponds to roughly 12 to 15 sessions.

In palliative situations or when patients are frail, very short schedules may be used. For indolent lymphoma, very low–dose radiotherapy can sometimes be given in as few as 2 sessions, and other symptom-relief regimens may involve only a small number of treatments. Your radiation oncologist will recommend the exact number of sessions based on the type and stage of lymphoma, the goals of treatment, and your overall health.

What Is Palliative Radiotherapy for Lymphoma?

Palliative radiotherapy for lymphoma is radiation treatment given to relieve symptoms rather than to cure the disease. It is used when lymphoma has come back, is widespread, or when intensive treatments like high-dose chemotherapy, transplant, or CAR T-cell therapy are not suitable or no longer effective.

In this setting, radiotherapy is usually focused on specific problem areas—for example, a large mass causing pain, pressure on nerves or the spinal cord, breathing difficulty, swallowing problems, or risk of bleeding. Because lymphoma cells are very sensitive to radiation, even modest doses over a short course can quickly shrink these areas and improve symptoms, often within days to weeks.

Palliative radiotherapy is typically planned to be as simple and convenient as possible, with fewer sessions and lower overall doses than curative treatment, to minimize side effects and travel burden. It can often be delivered with little or no additional immunosuppression, which makes it an attractive option for older, frail, or heavily pretreated patients. While the main goal is comfort and quality of life, in some cases—especially when disease is limited—palliative courses can also provide durable local control.

Gard et al. reported a large single-institution retrospective series on primary cutaneous B-cell lymphoma (PCBCL) treated with low-dose focal radiotherapy, published in 2025 in the International Journal of Radiation Oncology • Biology • Physics. They analyzed 174 follicle center or marginal zone lesions in 49 patients treated between 2016 and 2024, focusing on freedom from treatment failure (FFTF), defined as the need for retreatment of the same lesion. Most lesions (135) received 4 Gy; for all 4 Gy lesions, 1- and 2-year FFTF were about 77% and 69%. Among “de novo” lesions, 114 treated with 4 Gy had 1- and 2-year FFTF of 74.8%, whereas 13 treated with 8–12 Gy had 1- and 2-year FFTF of 100%, a statistically significant advantage (p=0.043).

Initial response rates were similar between dose groups, but lesions treated with 4 Gy required retreatment more often, with approximately one quarter failing within a year. Toxicity was minimal in both arms, with no grade ≥3 events and mainly mild skin changes. The authors conclude that while 4 Gy remains reasonable for purely palliative intent, doses of 8–12 Gy should be considered for PCBCL when more durable local control is desired, given the better FFTF and similarly low toxicity.

What Are The Recent Advances in Radiotherapy for Lymphomas?

Wallington et al., in a review published in Seminars in Radiation Oncology in 2025, examined the evolving role of radiotherapy in lymphoma patients undergoing CAR T-cell therapy. They highlight that while CAR T has transformed outcomes for relapsed/refractory DLBCL, many patients still progress before or after infusion, and patterns of failure are often dominated by local disease progression.

The authors describe how bridging and early salvage radiotherapy can provide rapid cytoreduction, palliate symptoms, and potentially enhance CAR T efficacy through modulation of the tumor microenvironment and immune effects, and they emphasize the need for prospective trials to define which patients benefit most, how to sequence RT with CAR T, and how to optimize dose and field design in this setting.

Oertel et al., in a 2024 article in Leukemia (a Nature journal), reported long-term results from the phase 3 R-MegaCHOEP trial evaluating consolidative radiotherapy in younger high-risk patients with advanced aggressive B-cell lymphoma.

Among 261 patients, 120 received RT, most often to mediastinal or para-aortic sites, with a median dose of 36 Gy in 1.8 Gy fractions. In patients with bulky disease (≥7.5 cm), consolidative RT significantly improved 10-year outcomes compared with no RT, with event-free survival of 64% vs 35%, progression-free survival of 68% vs 47%, and overall survival of 72% vs 59%, without a significant increase in secondary malignancies, supporting RT as part of first-line therapy in this group.

How Can Patients Support Their Health During Radiotherapy for Lymphoma?

During radiotherapy, there is a lot you can do to help your body cope with treatment and recover well.

Staying active in a gentle way is important. Light daily activity, such as walking or stretching, can help reduce tiredness, support mood, and keep your muscles and joints flexible. It’s usually better to move a little every day than to push yourself hard on some days and then feel exhausted.

Nutrition and hydration make a big difference. Try to eat small, regular meals with a balance of protein, fruits, vegetables, and whole grains, and drink enough fluids to keep your urine pale yellow. If you lose your appetite, feel nauseated, or are losing weight, let your team know—they can suggest changes or refer you to a dietitian.

Skin care in the treatment area is also important. Use only the soaps, creams, or lotions recommended by your radiation team, avoid rubbing or scratching the skin, and protect the area from strong sun exposure. Do not apply new products on the treated skin without checking first.

Rest and sleep matter. Many people feel more tired as treatment goes on, so it helps to plan short rests during the day, aim for regular bedtimes, and pace your activities. Let family and friends know that you may need extra help with chores or childcare.

Emotional and mental wellbeing should not be overlooked. Anxiety, mood changes, and worry about the future are common. Talking openly with your care team, a counselor, or a support group can be very helpful. Some people benefit from relaxation techniques, breathing exercises, or mindfulness.

Finally, keep close communication with your treatment team. Report new or worsening symptoms, such as shortness of breath, fevers, severe pain, or trouble swallowing. Take medications exactly as prescribed and attend all scheduled visits and imaging. By working together with your healthcare team and taking care of your body and mind, you can support your health throughout radiotherapy and recovery.

Written By Aren Karapetyan, MD