Follicular lymphoma

Follicular lymphoma is a type of non-Hodgkin lymphoma that begins in B lymphocytes, or B cells. These white blood cells normally help the immune system respond to infections.

The abnormal cells often collect in lymph nodes, including those in the neck, armpits, chest, abdomen, and groin. Follicular lymphoma can also affect the bone marrow, spleen, blood, or other tissues.

Most follicular lymphomas grow slowly and are described as indolent. You may feel well when the condition is found, and some people do not need treatment straight away.

However, follicular lymphoma usually needs lifelong follow-up because it can return after treatment. In some people, it changes into a faster-growing lymphoma. This is called transformation.

The condition is divided into stages according to where it is in the body. Many people are diagnosed at an advanced stage but still live for years with the lymphoma under good control.

The most common sign is one or more enlarged lymph nodes. These usually feel like painless lumps under the skin, often in the neck, armpit, or groin. They may remain stable or slowly grow.

Other possible symptoms include:

• Tiredness that does not improve with rest
• Unexplained fever
• Drenching night sweats
• Unintended weight loss
• Abdominal fullness, discomfort, or swelling
• Shortness of breath or a persistent cough
• Frequent or difficult-to-clear infections
• Easy bruising, bleeding, or unusual paleness

Fever, drenching night sweats, and significant unexplained weight loss are sometimes called B symptoms. They can influence staging and treatment decisions, although they have many possible causes.

Lymphoma in the bone marrow can reduce blood-cell production. This may cause tiredness or breathlessness, bruising or bleeding, or an increased risk of infection.

Some people have no symptoms. Their lymphoma may be discovered during an examination, scan, or blood test performed for another reason.

Follicular lymphoma develops when a B cell acquires genetic changes that allow it to survive and multiply abnormally.

Many cases involve a change affecting the BCL2 gene, which helps abnormal cells avoid their normal self-destruction process. This change is usually acquired during life rather than inherited.

The exact trigger is unknown. Follicular lymphoma is not caused by something you did and is not contagious.

It is more common in older adults, although younger adults can develop it. Certain immune-system problems may increase the likelihood of lymphoma generally, but many people have no clear risk factor.

Having a relative with lymphoma may slightly increase risk, but follicular lymphoma is not usually passed directly through families. Routine genetic testing of relatives is generally not recommended.

A biopsy is needed to confirm follicular lymphoma. All or part of an enlarged lymph node is removed and examined in a laboratory. Removing a whole node, when practical, often gives the clearest information about its internal structure.

The sample is tested for proteins and genetic changes that identify lymphoma cells. A needle biopsy may be used, but another biopsy may be needed if the sample is too small or transformation is suspected.

The laboratory assigns a grade based on how the cells look under a microscope. Grades 1, 2, and 3A are usually treated as slow-growing lymphoma. Grade 3B behaves more like an aggressive lymphoma and is generally managed differently.

Tests used to establish the stage and assess general health may include:

• Blood counts and checks of liver and kidney function
• CT or PET-CT scans
• Tests for infections that could affect treatment
• A bone marrow biopsy in selected situations

Doctors also consider symptoms, blood results, the size and location of affected nodes, and whether organs are affected. These details may be more important to treatment planning than stage alone.

Treatment depends on how the lymphoma is behaving and whether it is causing problems.

If you feel well and the lymphoma is not threatening an organ or disrupting blood production, active monitoring, also called watch and wait, may be recommended. This involves planned appointments, examinations, and blood tests, with scans when clinically needed.

Active monitoring does not mean the condition is being ignored. Starting treatment early has not been shown to benefit everyone with symptom-free, low-burden follicular lymphoma. Treatment can begin if symptoms develop or the lymphoma starts causing harm.

Radiotherapy may be used when lymphoma is limited to one area. It directs high-energy radiation at affected lymph nodes and can sometimes cure localized follicular lymphoma. Long-term follow-up remains important.

If several areas are affected, treatment may include an antibody that targets B cells. Rituximab and obinutuzumab target a B-cell protein called CD20. An antibody may be given alone or with chemotherapy.

Some people receive maintenance treatment after the initial course, meaning an antibody is continued at intervals to lengthen remission. The possible benefit is balanced against side effects, including infections.

If lymphoma returns, treatment depends on the previous response, earlier side effects, biopsy findings, and overall health. Options may include another antibody-based treatment, medicines that affect lymphoma-cell growth, or treatments that help immune cells recognize lymphoma.

Specialist centres may offer bispecific antibodies or CAR T-cell therapy after several previous treatments. CAR T-cell therapy modifies some of your immune cells so they can attack lymphoma. Stem cell transplantation is used less often but may be considered for selected people.

Supportive care may include vaccinations, infection prevention, treatment for low blood counts, and help with nausea or fatigue. Your oncology team should explain expected benefits, side effects, and practical effects before treatment begins.

Follicular lymphoma can reduce normal blood-cell production if it affects the bone marrow. Enlarged lymph nodes or the spleen may also cause discomfort or pressure on nearby organs.

Treatment can weaken the immune system, increase infection risk, and reduce how well some vaccines work. Other possible effects include fatigue, low blood counts, or nerve symptoms, depending on the medicines used.

Follicular lymphoma can transform into a faster-growing lymphoma, most often diffuse large B-cell lymphoma. Warning signs include a lump growing quickly, new B symptoms, pain in a previously painless node, or a sudden change in certain blood results. These do not prove transformation, but they require prompt assessment and often another biopsy.

Living with an untreated cancer or the possibility of recurrence can cause anxiety. Clear follow-up plans, psychological support, and peer groups may help.

There is no established way to prevent follicular lymphoma. The cell changes that cause it are usually acquired without an identifiable trigger.

No particular food, activity, or ordinary infection is known to cause it. Healthy habits may support general health but cannot guarantee prevention.

Relatives do not usually need screening, and there is no standard screening test for people without symptoms.

Follicular lymphoma often follows a long course. Some people remain well without treatment for a considerable time. Others need treatment soon after diagnosis because of symptoms, large lymph nodes, low blood counts, or pressure on an organ.

Treatment often produces a remission, meaning signs of active lymphoma become much smaller or cannot be detected with current tests. Remission is not always a cure, and the lymphoma may return.

The pattern varies. Some remissions last many years, while others are shorter. A faster return may lead your specialist team to recommend a different approach.

Follow-up usually includes a symptom review, physical examination, and blood tests. Scans are used according to your clinical situation rather than automatically at every visit. Between appointments, report a steadily enlarging lump, persistent fever, drenching night sweats, unexplained weight loss, or a clear decline in energy.

Many people continue working, travelling, exercising, and caring for family. Adjustments may be needed during treatment or periods of fatigue. If your immune system is weakened, follow your team's advice about vaccines, infections, travel, and exposure to illness.

Arrange a routine medical appointment for a painless lump that persists or enlarges. Also seek assessment for unexplained weight loss, repeated night sweats, persistent fever, unusual tiredness, or frequent infections.

If you have follicular lymphoma, contact your lymphoma team promptly about changes between visits. A rapidly growing node, new pain in a node, or new B symptoms may need earlier testing.

During treatment, follow the instructions you have been given about fever and infection. Contact your treatment service urgently for fever, shaking chills, a worsening cough, painful urination, or feeling suddenly unwell. Do not wait for your next routine appointment.

Seek emergency help for:

• Severe difficulty breathing or sudden chest pain
• Rapid swelling of the face or neck
• New leg weakness, numbness, or difficulty walking
• New loss of bladder or bowel control
• Heavy bleeding, fainting, or severe confusion

These symptoms can indicate pressure on an airway or spinal cord, serious infection, or another condition needing immediate care.

Is follicular lymphoma cancer?

Yes. It is a cancer of B lymphocytes, although it usually grows more slowly than aggressive lymphomas.

Can follicular lymphoma be completely cured?

Sometimes. Radiotherapy may cure lymphoma limited to one area. More widespread disease is usually considered manageable rather than curable, but treatment can produce long remissions.

Why am I not getting treatment straight away?

If the lymphoma is not causing symptoms or organ problems, active monitoring can avoid unnecessary side effects without reducing the chance of successful treatment later. You still receive planned follow-up.

How quickly does follicular lymphoma grow?

It commonly grows slowly, but the pace varies and can change. Rapid node growth or new symptoms should be assessed.

Can follicular lymphoma turn into an aggressive lymphoma?

Yes, but transformation does not happen to everyone. Report a rapidly enlarging lump, new pain, fevers, drenching sweats, or unexplained weight loss promptly.

Will follicular lymphoma shorten my life?

It can affect life expectancy, but many people live with it for years and have long remissions. Outlook depends on its behaviour, treatment response, general health, and whether transformation occurs.