Non-Hodgkin’s Lymphoma Unspecified Histology Indolent

Indolent non-Hodgkin’s lymphoma is a slow-growing type of blood cancer that develops in the lymphatic system. While it usually cannot be cured in advanced stages, most patients can live for many years with proper management.

Table of contents

• What is indolent non-Hodgkin’s lymphoma
• How common is this disease
• Signs and symptoms
• What causes this disease
• How doctors diagnose the disease
• Types of indolent lymphoma
• Treatment approaches
• Life expectancy and outlook

What is indolent non-Hodgkin’s lymphoma

Indolent non-Hodgkin’s lymphoma is a type of slow-growing blood cancer that forms in the lymphatic system, which is part of the body’s immune system that helps fight infections and disease^[1]. The lymphatic system includes lymph nodes, spleen, bone marrow, and other organs that protect the body from germs.

In this disease, certain white blood cells called lymphocytes undergo changes in their genes and begin to grow abnormally. These abnormal cells usually form in lymph nodes and create growths called tumors. However, they can also appear in other organs of the lymphatic system^[1].

The word “indolent” means the lymphoma tends to grow and spread slowly, which is why it may not cause noticeable symptoms for a long time^[5]. This is different from aggressive lymphomas, which grow and spread more quickly and often need immediate treatment.

Most indolent lymphomas develop from B cells, a type of lymphocyte that makes antibodies to help fight infections. About 85% of all non-Hodgkin lymphomas arise from B cells^[1].

How common is this disease

Non-Hodgkin lymphoma is relatively common. It is the 8th most common cancer diagnosis in the United States, with approximately 80,620 new cases expected in 2024^[1]. It is also the 11th most common cancer worldwide^[1].

Indolent lymphomas make up about 35 to 45 percent of all non-Hodgkin lymphomas^[12]. The disease mainly affects adults, with the average age at diagnosis being around 60 years old^[17]. It affects both men and women, though being male slightly increases the risk^[5].

Signs and symptoms

Because indolent lymphoma grows slowly, many people do not have any noticeable symptoms at first^[17]. When symptoms do appear, they are often mild and develop gradually over time.

The most common symptom is painless swelling in the neck, armpits, or groin. This swelling happens when lymph nodes in these areas become enlarged^[1].

Other symptoms that may develop include:

• Persistent tiredness that does not improve with rest
• Fever without an obvious cause
• Night sweats that are so intense they soak the bedsheets
• Unintended weight loss, particularly losing 10% of total body weight over six months
• Chest pain or trouble breathing
• Belly pain or feeling of fullness
• Loss of appetite^[1]

Healthcare providers pay special attention to three symptoms called B symptoms, which include fever, night sweats, and unexplained weight loss. These symptoms help doctors understand the type and severity of the lymphoma^[1].

It is important to remember that many other conditions can cause these same symptoms. Having one or more of these symptoms does not necessarily mean someone has lymphoma. However, it is wise to contact a healthcare provider if these changes last for several weeks^[1].

What causes this disease

Indolent non-Hodgkin lymphoma develops when genes inside lymphocytes change or mutate at some point during a person’s lifetime^[1]. These changes cause the lymphocytes to grow abnormally and form tumors.

Several factors can increase the risk of developing non-Hodgkin lymphoma. Being older increases risk, as the disease is more common in people over 60^[5]. Having a weakened immune system, whether from certain medical conditions or medications that suppress the immune system, also raises risk^[5].

The disease may result from various causes including changes in chromosomes, exposure to certain toxins, infections, and long-lasting inflammation in the body^[2]. However, in most cases, doctors cannot identify a specific cause.

How doctors diagnose the disease

Diagnosing indolent non-Hodgkin lymphoma typically begins with a physical examination. A healthcare provider checks for swollen lymph nodes in the neck, underarms, and groin, and examines whether the spleen or liver are enlarged^[21].

If lymphoma is suspected, several tests may be performed. Blood and urine tests help rule out infections or other diseases^[21].

Imaging tests create pictures of the inside of the body to look for lymphoma cells. These may include CT scans (computed tomography), MRI (magnetic resonance imaging), and PET scans (positron emission tomography)^[21].

The most important test is a lymph node biopsy, where doctors remove all or part of a lymph node to examine under a microscope. Laboratory tests on this tissue sample can confirm whether lymphoma is present and identify the specific type^[21].

Doctors may also perform bone marrow tests, which involve collecting cells from the bone marrow using a needle, usually from the hip bone. These tests check whether lymphoma has spread to the bone marrow^[21].

Types of indolent lymphoma

There are several types of indolent non-Hodgkin lymphoma. Each type has slightly different characteristics and behaviors^[8].

Follicular lymphoma is the most common type of indolent lymphoma. It accounts for about 20 to 30 percent of all non-Hodgkin lymphomas. About 2,300 people are diagnosed with follicular lymphoma each year in the UK. It mainly affects adults over age 60 but can occur at any age^[8].

Marginal zone lymphoma is a group of slow-growing lymphomas that start in an area of lymphoid tissue called the marginal zone. This group includes several subtypes. The most common is MALT lymphoma (mucosa-associated lymphoid tissue), which often starts in the stomach. About 2,600 people are diagnosed with marginal zone lymphoma each year in the UK^[8].

Small lymphocytic lymphoma (SLL) is a slow-growing type that is very similar to a condition called chronic lymphocytic leukemia^[8].

Mantle cell lymphoma is a rare type that affects about 600 people per year in the UK. It looks like a low-grade lymphoma under the microscope but often grows more quickly, so doctors may treat it more like a high-grade lymphoma^[8].

Sometimes, indolent lymphomas can change into a faster-growing type. Doctors call this transformation^[8].

Treatment approaches

Treatment for indolent non-Hodgkin lymphoma varies depending on several factors, including the disease stage, symptoms, age, and overall health of the patient^[11].

Because indolent lymphoma grows slowly, patients without symptoms may not need immediate treatment. Instead, doctors may recommend a “watch and wait” approach, which is still considered the standard care for people without symptoms^[12]. During this time, doctors closely monitor the disease with regular check-ups.

When treatment is needed, several options are available. For patients with early-stage disease limited to one or two nearby areas, radiation therapy alone can be very effective and may even cure the disease^[9].

For more advanced disease, treatment typically involves immunotherapy, which uses the body’s immune system to fight cancer. The most common immunotherapy drug is rituximab, an antibody that targets B cells^[12].

Chemotherapy uses drugs to kill cancer cells. It is often combined with immunotherapy in a treatment approach called chemoimmunotherapy^[11].

Although indolent lymphoma responds well to treatment, the disease often comes back over time. However, patients can often be treated again successfully if the disease remains slow-growing^[9].

Most chemotherapy for non-Hodgkin lymphoma can be given in an outpatient setting at an infusion clinic, where specially trained nurses administer the treatment under a doctor’s supervision^[11].

Life expectancy and outlook

Indolent non-Hodgkin lymphoma has a relatively good outlook, even though it usually cannot be completely cured in advanced stages^[9]. The average life expectancy after diagnosis is approximately 12 to 14 years, though many people live much longer^[17].

For all types of non-Hodgkin lymphoma combined in England, approximately 80 out of every 100 people survive for one year or more after diagnosis, and around 65 out of every 100 people survive for five years or more^[18].

For follicular lymphoma specifically, around 85 in 100 people survive for 5 years or more after diagnosis^[18]. Some people with follicular lymphoma have an even better outlook, with almost all those in the low-risk group surviving for 5 years or more^[18].

The disease can be kept under control for several years with proper treatment, even though it may come back^[8]. People with indolent lymphoma are living longer than ever before, thanks to improvements in treatments, particularly the development of targeted therapies^[1].

Survival depends on many individual factors, including the specific type of lymphoma, stage of disease, age, overall health, and how well the lymphoma responds to treatment. A doctor can provide more specific information about individual outlook based on these personal factors^[18].