Indolent lymphoma is a type of non-Hodgkin lymphoma that grows and spreads particularly slowly. Because of this, it may not cause any symptoms.

Non-Hodgkin lymphoma is a blood cancer that starts in the lymphatic system. The lymphatic system is part of the immune system. It includes the tissues and organs that carry infection-fighting white blood cells around the body.

In non-Hodgkin lymphoma (NHL), white blood cells start to multiply in an abnormal way and collect in parts of the lymphatic system, such as the lymph nodes.

The way NHLs grow is categorized in the following ways:

Growth ratePrevalence in NHL
Indolent lymphomasIndolent lymphomas are the slowest growing of all NHLs.They account for around 40% of all cases of NHL.
Aggressive lymphomasAggressive lymphomas grow quickly.They account for around 60% of all cases of NHL.

Sometimes, indolent lymphomas can become aggressive lymphomas.

This article will explain the prevalence of indolent lymphomas. It will list the different types and stages of the condition, its outlook, and symptoms a person with indolent lymphoma might experience. It will also describe the importance and different options of treatment.

a doctor is checking the lymph nodes of a person with indolent lymphomaShare on Pinterest

About 40% of all people with NHL have indolent lymphoma.

In the United States, NHL accounts for around 4% of all cancers. The American Cancer Society estimates that as of 2021, NHL is diagnosed in around 81,560 people (including adults and children).

NHL can affect people of any age. It is more common after the age of 75. However, it is also one of the most common cancers among children, teens, and young adults.

White people are more likely than Black people to develop NHL. People assigned male at birth are more likely than people assigned female at birth to develop NHL.

The subtypes of indolent lymphoma include:

Follicular lymphoma

Follicular lymphoma (FL) usually occurs in multiple lymph nodes, as well as in the bone marrow. The average age at diagnosis of FL is 65 years.

FL is the most common lymphoma in the U.S. It is the most common type of indolent lymphoma. It makes up 35% of all NHLs and 70% of all indolent lymphomas.

FLs may respond well to treatment. However, it can be challenging to cure completely. Doctors may delay treatment until the FL starts causing symptoms.

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL)

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are both indolent types of cancer. They may affect the blood, bone marrow, or lymph nodes.

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

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

Marginal zone lymphomas (MZL) account for around 5–10% of NHLs. They develop in a particular region at the edge of normal lymphoid tissues, called the marginal zone.

There are different subtypes of MZL, which arise in different areas of the lymphatic system.

Cutaneous T-cell lymphoma

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, which primarily involves the skin
  • sézary syndrome, where malignant white blood cells (lymphocytes) accumulate in the blood

Treatment will depend on the type and stage of CTCL.

Lymphoplasmacytic lymphoma and Waldenström macroglobulinemia

These rare indolent lymphomas originate in B-lymphocyte cells and cause thickening of the blood. This can lead to headache, confusion, and visual blurring.

Waldenström macroglobulinemia can cause weakness as it causes the blood to thicken. It can increase a person’s risk for blood clots or stroke.

Treatment only begins if symptoms develop. As this cancer advances, it can involve the lungs, gastrointestinal tract, and other organs.

To determine the extent of indolent lymphoma, a medical team will perform a series of tests. They will compare the results of the tests against a staging system to find out what stage the disease is at.

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 above and below 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, research has revealed possible risk factors, including:

  • age, since people over 75 have a higher risk
  • family history of lymphoma
  • HIV
  • having other viruses, such as human T-cell lymphotropic virus and Epstein-Barr virus
  • having an inherited immune disorder, such as hypogammaglobulinemia or Wiskott-Aldrich syndrome
  • being exposed to high levels of ionizing radiation
  • certain ingredients in herbicides and pesticides

A person can live with indolent lymphoma for several years before showing any symptoms since it is slow-growing. A person may have fewer symptoms than a person with aggressive lymphoma. However, the symptoms may be similar.

The most common symptoms of NHL indolent lymphoma are:

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.

A 2020 study focused on follicular lymphoma, the most common type of indolent lymphoma. It highlighted the positive survival rate for this type of lymphoma, stating the 5-year overall survival rate was 92% for all participants in the study.

Researchers also highlighted the rapid advances in treatment that can impact this outlook and reiterated the importance of early diagnosis.

Learn about stage 4 lymphoma here.

Many people who eventually receive a diagnosis of NHL visit their doctor about a lump they have found that has not gone away. Sometimes lumps are found through routine check-ups.

If a doctor suspects lymphoma, they can order a series of tests, exams, and scans to confirm the diagnosis. These include:

The treatment for indolent lymphoma depends on the subtype of NHL being treated, the stage it is, and any other health conditions they may have.

All treatment plans will be planned by a team of healthcare professionals with expertise in treating lymphoma.

According to the National Cancer Institute, nine standard treatments are available:

Through clinical trials, researchers are investigating new treatments, including vaccine therapy. With ongoing research, treatment options are improving all the time.

Indolent NHL is not curable. However, it can respond very well to treatment. Some doctors will suggest people with indolent lymphoma wait to receive treatment until they show symptoms. This 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.

After being treated for indolent NHL, some people may go on to experience long-term conditions. 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 treatment. They can discuss the likelihood of this with a doctor.
  • Secondary cancers: Some treatments kill healthy cells as well as cancer 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.