Small lymphocytic lymphoma

Overview

Small lymphocytic lymphoma (SLL) is a type of lymphoma. Lymphoma is cancer that affects the lymphatic system. The lymphatic system is made up of organs, glands, tubelike vessels and clusters of cells called lymph nodes. It's part of the body's germ-fighting immune system.

There are many types of lymphoma. Lymphoma types are often divided into two categories: Hodgkin lymphoma and non-Hodgkin lymphoma. Small lymphocytic lymphoma is a type of non-Hodgkin lymphoma.

Small lymphocytic lymphoma can affect the lymph nodes, spleen, blood, bone marrow and other parts of the body. It usually grows slowly. Treatments usually can't cure small lymphocytic lymphoma, but they may control it for a long time. People with this type of cancer often have a good prognosis.

Not everyone needs treatment right away for small lymphocytic lymphoma. When needed, treatments for small lymphocytic lymphoma may include a "watch and wait" approach, targeted therapy, chemotherapy, immunotherapy and radiation therapy. Other treatment options may include bone marrow transplant, also known as bone marrow stem cell transplant, CAR-T cell therapy and clinical trials.

Some people wonder how small lymphocytic lymphoma relates to another disease called chronic lymphocytic leukemia. Healthcare professionals often mention these together because they are thought to be the same disease. However, in small lymphocytic lymphoma, the cancer cells are most often found in the lymph nodes. In chronic lymphocytic leukemia, the cancer cells are most often found in the blood and bone marrow.

Symptoms

Small lymphocytic lymphoma symptoms may not happen right away. Symptoms might develop as the cancer progresses. When symptoms happen, they may include:

• Swollen lymph nodes, which might feel like a lump under the skin. They happen most often in the neck, armpit and groin.
• Fever.
• Drenching night sweats.
• Fatigue.
• Weight loss without trying.
• Loss of appetite.
• Pain in the upper left part of the belly, which may be caused by an enlarged spleen.

When to see a doctor

Make an appointment with a healthcare professional if you have any symptoms that worry you.

Causes

It's not clear what causes small lymphocytic lymphoma. Cancer happens when cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time. In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to make many more cells quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells. In small lymphocytic lymphoma, the cancer cells can build up in the lymph nodes, spleen, blood, bone marrow and other parts of the body.

Small lymphocytic lymphoma gets its name from the kind of cell that makes up this cancer. This cancer starts in germ-fighting white blood cells called lymphocytes. When healthcare professionals look at the cells with a microscope, the cancer cells appear round and small. These are sometimes called smudge cells.

Risk factors

Factors that may increase the risk of small lymphocytic lymphoma include:

• Your age. Small lymphocytic lymphoma happens most often in adults older than 55.
• Your race. White people are more likely to develop small lymphocytic lymphoma than are people of other races.
• Exposure to harmful substances. Certain herbicides and insecticides, including Agent Orange used during the Vietnam War, have been linked to an increased risk of small lymphocytic lymphoma. Excessive exposure to radiation, rubber and benzene also may increase the risk.
• Family history of blood and bone marrow cancers. A family history of small lymphocytic lymphoma or other blood and bone marrow cancers may increase your risk.
• A condition that causes excess lymphocytes. Monoclonal B-cell lymphocytosis (MBL) causes an increased number of a type of lymphocyte, called B lymphocytes, in the blood. For a small number of people with MBL, the condition may develop into small lymphocytic lymphoma. If you have MBL and have a family history of small lymphocytic lymphoma, you may have a higher risk of developing cancer.

Complications

Small lymphocytic lymphoma may cause complications such as:

• Frequent infections. If you have small lymphocytic lymphoma, you may get infections more often. These infections can be serious. Sometimes infections happen because your blood doesn't have enough germ-fighting antibodies, called immunoglobulins. Your healthcare professional might recommend regular immunoglobulin infusions.
• A switch to a more aggressive form of cancer. A small number of people with small lymphocytic lymphoma may develop a more aggressive form of cancer called diffuse large B-cell lymphoma. This is sometimes referred to as Richter syndrome.
• Increased risk of other cancers. People with small lymphocytic lymphoma have an increased risk of other types of cancer. These include skin cancer and cancers of the lung and the digestive tract.
• Immune system attacks. A small number of people with small lymphocytic lymphoma may develop an immune system reaction that causes the disease-fighting cells of the immune system to mistakenly attack the red blood cells. This is called autoimmune hemolytic anemia. The immune system also may attack the blood cells that help blood clot, called platelets. This attack is called autoimmune thrombocytopenia.