Indolent lymphoma is a type of non-Hodgkin’s lymphoma (NHL) that grows and spreads particularly slowly. Because of this, it may not cause any symptoms at first.
NHL is a type of blood cancer that begins in the lymphatic system, which is part of the immune system. The lymphatic system includes tissues and organs, such as lymph nodes, the spleen, and bone marrow, that help transport infection-fighting white blood cells throughout the body.
The Leukemia and Lymphoma Society (LLS) states that non-Hodgkin’s lymphoma (NHL) develops when certain white blood cells (usually B cells or T cells) grow and multiply at an abnormal rate. These cancerous cells can build up in lymph nodes or other parts of the lymphatic system to form tumors or interfere with the body’s ability to fight infections.
According to the LLS, specialists categorize NHL growth in the following ways:
| Growth rate | Prevalence in NHL | |
|---|---|---|
| Indolent lymphomas | Indolent lymphomas are the slowest-growing of all NHLs. | Accounts for around 40% of all people with NHL. |
| Aggressive lymphomas | Aggressive lymphomas grow quickly. | Accounts for around 60% of all people with NHL. |
Sometimes, indolent lymphomas can become aggressive lymphomas.
This article will explore the occurrence of indolent lymphomas, outline their types and stages, and explain the symptoms a person may experience. It will also discuss outlook, treatment options, and why early diagnosis and management matter.
According to the LLS, about 40% of all people with NHL have indolent lymphoma.
The
According to the ACS, NHL can affect people of any age. It is more common after the age of 65. However, it is also one of the most common cancers among children, teens, and young adults.
They also indicate that white people are more likely than Black people to develop NHL. People assigned male at birth are more likely to develop NHL than those assigned female.
The subtypes of indolent lymphoma include:
Follicular lymphoma
Follicular lymphoma (FL) usually occurs in multiple lymph nodes and the bone marrow. A 2020 clinical update article notes that the median age at diagnosis of FL is
FL is the most common form of indolent lymphoma, accounting for approximately 20-25% of all new NHL diagnoses and as
FLs may respond well to treatment. However, it can be challenging to cure completely. Doctors may delay treatment until the FL starts causing symptoms. This is known as watchful waiting, a common approach in asymptomatic, low-burden FL.
CLL and SLL
Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are indolent types of cancer. The National Cancer Institute (NCI) states that both
The Lymphoma Research Foundation writes that CLL and SLL can cause different symptoms depending on where the tumors have formed. Symptoms are usually non-specific and generalized, including:
- swollen lymph nodes
- fatigue
- fever
- unexplained weight loss
Lymphoma Action adds that CLL and SLL may not cause any symptoms for several years, meaning treatment may not be immediately necessary. Treatment usually aims to manage the cancer rather than cure it.
Marginal zone lymphomas
The ACS indicates that marginal zone lymphomas (MZL) account for around
Different subtypes of MZL arise in various areas of the lymphatic system.
Cutaneous T-cell lymphoma
According to the American Academy of Dermatology Association (AAD), cutaneous T-cell lymphoma (CTCL) is rare. It develops in T-cells in the skin and can spread to lymph nodes, blood, and other organs. There are two subtypes:
- Mycosis fungoides: This is the most common form of CTCL. It affects the skin primarily.
- Sézary syndrome: This is a more aggressive form of CTCL where malignant white blood cells (lymphocytes) accumulate in the blood
Treatment will depend on the type and stage of CTCL. According to the Cutaneous Lymphoma Foundation, therapies include topical therapies, phototherapy, radiation, systemic medications, or targeted treatments.
Lymphoplasmacytic lymphoma and Waldenström macroglobulinemia
Lymphoplasmacytic lymphoma is a rare, slow-growing type of non-Hodgkin’s lymphoma that originates in B-lymphocyte cells and often produces an abnormal IgM antibody. When this antibody is present, the condition is known as Waldenström macroglobulinemia.
According to the
Treatment only begins when symptoms develop. As this cancer advances, it can involve the lungs, gastrointestinal tract, and other organs.
A medical team will perform a series of tests to determine the extent of indolent lymphoma. They will compare the results of the tests against a staging system to find out what stage the disease is at.
According to the LLS, the stages are as follows:
- Stage I is localized, involving one lymph node region or a single organ.
- Stage II affects two or more lymph node regions on the same side of the diaphragm.
- Stage III affects two or more lymph node regions on both sides of the diaphragm.
- Stage IV is when the disease is widespread, affecting multiple organs, with or without lymph node involvement.
However, the staging of NHL can vary depending on its type.
The cause of NHL, including indolent lymphoma, is unknown. However, the ACS lists the following possible
- age, since people over 65 have a higher risk
- family history of lymphoma
- HIV
- certain viral infections, like Epstein-Barr virus (EBV) or human T-cell lymphotropic virus (HTLV-1)
- inherited immune disorders, including hypogammaglobulinemia and Wiskott-Aldrich syndrome
- exposure to high levels of ionizing radiation
- exposure to certain chemicals, such as those found in herbicides and pesticides
The LLS states that a person may live with slow-growing indolent lymphoma for several years before showing any symptoms. When symptoms do appear, they are often milder than those of aggressive lymphoma, but there may be some overlap.
The LLS lists some of the most common symptoms of indolent lymphoma. These include:
- swollen lymph nodes
- fever
- drenching night sweats
- persistent fatigue or weakness
- loss of appetite
- unexplained weight loss
- bloating or a feeling of fullness
- itchy skin
- enlargement of the spleen or liver
- rashes or skin lumps
- pain in the chest, abdomen, or bones
Every person’s NHL is different. Their outlook depends on the subtype of lymphoma they have, where it started, and how their body responds to treatment.
According to the 2024 SEER database, the 5-year relative survival rate for follicular lymphoma is about
The relative survival rate suggests how long someone with a condition may live after their diagnosis compared to someone without the condition of the same race, sex, and age over a specific time. This is different from overall survival rate, which is a percentage of people still alive for a specific time after diagnosis of a condition.
It’s most important to remember that figures are estimates, and everyone is different. Talk with your doctor about your specific condition.
A 2024 study looking at follicular lymphoma that had returned or worsened 2 years after starting treatment (called POD24) found that the outlook was less optimistic. Overall survival for this group 5 years after diagnosis is around 71%.
Survival rate refers to the number of people who are still alive for a specific length of time after a particular diagnosis. For example, a 5-year survival rate of 50% of people means that half of the people are still alive at least five years after being diagnosed. It is important to remember that these figures are estimates and are based on previous medical studies.
Talk with your doctor about the outlook for your specific condition.
Researchers also highlighted that rapid advances in treatment can affect this outlook and reiterated the importance of early diagnosis.
Many people who eventually receive a diagnosis of NHL visit their healthcare professional because of a lump that doesn’t go away. The lump may be in the neck, armpit, or groin. Sometimes, doctors find lumps during routine check-ups.
If a doctor suspects lymphoma, they may order a series of tests, exams, and scans to confirm the diagnosis. According to the ACS, these
- medical history and physical exam
- biopsy
- X-ray
- CT scan
- MRI scan
- ultrasound
- PET scan
- bone scan
- blood tests
- echocardiogram
- pulmonary function test
Treatment for indolent lymphoma depends on the specific subtype of NHL, the stage of the disease, and any other health conditions the person may have.
A team of healthcare professionals with expertise in treating lymphoma will determine all treatment plans.
According to the
- radiation therapy
- chemotherapy
- immunotherapy
- targeted therapy
- plasmapheresis
- watchful waiting
- antibiotic therapy
- surgery
- stem cell transplant
Researchers are investigating new treatments, including vaccine therapy, through clinical trials. With ongoing research, treatment options are improving constantly.
Indolent NHL is not curable. However, it often responds very well to treatment. The LLS notes that some doctors will suggest people with indolent lymphoma wait to receive treatment until they show symptoms. This approach, known as watchful waiting, is safe as long as a person continues to undergo regular monitoring of the condition.
Untreated and unmonitored indolent lymphoma may develop into a more aggressive type.
The National Health Service (NHS) in the United Kingdom states that some people may experience long-term conditions after treatment for NHL. These include:
- A weakened immune system: This can mean a person is less able to fight off infections.
- Unsuitability for live vaccines: The body’s immune system may not be strong enough to fight the live virus they contain.
- Infertility: This can result from chemotherapy and radiotherapy.
- Sexual dysfunction: A person may experience sexual dysfunction with certain treatments. They can discuss the likelihood of this with a doctor.
- Secondary cancers: Some treatments kill noncancerous and cancerous cells, and damaged cells are more likely to turn cancerous than healthy cells.
- Increased risk of other conditions: People may be more likely to have heart disease and lung disease.
- Emotional distress: A diagnosis of indolent lymphoma can be a stressful experience and cause emotional or psychological challenges. A person should discuss the mental health resources available to them, including support groups, with their doctor.
Indolent lymphoma is the term for a set of slow-spreading blood cancers with no known cause. They are a type of NHL. Some people with indolent lymphoma do not experience symptoms for several years.
Treatment may begin after symptoms have started to show. Until this time, it is important for a person to undergo monitoring for the condition, or it may develop into a more aggressive type.
With early diagnosis and the appropriate treatment, a person can live with indolent lymphoma for many years.