A Patient's Guide to Chronic Lymphocytic Leukemia
New treatments offer hope for people with this typically slow-growing cancer.
Chronic lymphocytic leukemia is the most common type of blood cancer in adults. It makes up more than a third of all leukemia cases in people age 19 or older, with 90% of cases occurring in people older than age 50, according to the American Cancer Society. “The average age of diagnosis is 72, so certainly it’s a disease of older adults. Most patients are in their 60s and 70s,” says Dr. Nitin Jain, an oncologist with MD Anderson Cancer Center.
Chronic lymphocytic leukemia is extremely rare in children.
Chronic lymphocytic leukemia is a slow-growing or chronic type of cancer. It starts in the bone marrow in cells called lymphocytes, which normally develop into mature T cells or B cells that fight infection. These cells are also found in the lymph nodes.
For reasons we don’t fully understand, some lymphocytes (usually precursors to B cells) develop abnormally. They don’t fight infection and they don’t die off. Instead, they accumulate, overwhelm the bone marrow and keep new blood cells from developing – not just white blood cells but also platelets (which help the blood to clot) and red blood cells (which carry oxygen throughout the body).
Eventually, the leukemic cells spill into the blood and parts of the body, including the spleen, liver and lymph nodes.
Chronic Lymphocytic Leukemia – More General Information
Because chronic lymphocytic leukemia is a slower-growing cancer that takes longer to progress, some blood cells are still able to mature and circulate. For that reason, some people go for years without reporting any symptoms. “Patients can have this disease undiagnosed for many months to years before it comes to a doctor’s attention,” Jain notes.
Symptoms that can eventually occur include:
- Weakness and fatigue, caused by fewer red blood cells.
- Enlarged lymph nodes, caused by cancer cells accumulating there.
- Bruises beneath the skin, caused by fewer platelets.
- Recurrent infections and less ability to fight off infection, caused by fewer white blood cells.
- Shortness of breath.
- Night sweats.
- Weight loss.
- Loss of appetite.
- Feeling full without having eaten much.
- Flu-like symptoms such as fever and chills.
Jain says people usually find out they have chronic lymphocytic leukemia by accident. “They have routine blood work and their blood counts are abnormal,” he explains. Too many lymphocytes and too few red blood cells or platelets are a warning sign.
Further lab tests are often done with blood samples, including:
- Flow cytometry and cytochemistry tests. These look for certain proteins on the surface of cancer cells that distinguish them as chronic lymphocytic leukemia cells. The tests can help determine how aggressive leukemia cells are. Leukemic cells with low amounts of proteins called ZAP-70 and CD38 have better outcomes, according to the American Cancer Society. Jain says that about two-thirds of the time, chronic lymphocytic leukemia grows very slowly, but in some cases the cancer grows faster (although this is not considered an acute or extremely aggressive type of leukemia).
- Genetic tests such as fluorescence in situ hybridization assays. FISH tests look at the genetic makeup of the cancer cells. The results can help doctors determine your prognosis and treatment. “Certain genetic abnormalities such as Deletion 17p or TP53 lead to faster progression of the disease,” Jain says.
Imaging tests and bone marrow biopsies are rarely needed to diagnose chronic lymphocytic leukemia.
Results of these tests help doctors determine the stage of your cancer, which indicates how far the cancer has spread and the likelihood that the disease will progress and require treatment.
The Rai staging system classifies chronic lymphocytic leukemia as:
- Stage 0: Slightly elevated counts of white blood cells (lymphocytes).
- Stage 1: Enlarged lymph nodes.
- Stage 2: An enlarged liver or spleen.
- Stage 3: Anemia (a lack of red blood cells).
- Stage 4: Low platelet counts.
For many people with chronic lymphocytic leukemia, treatment isn’t necessary for years, if at all. “The most common practice is to watch and wait. We follow the patient every three to six months and make sure blood counts are stable and the patients are feeling well,” Jain says.
“Patients are not treated until they develop symptoms like night sweats or anemia. A third of patients are never treated,” says Dr. Anthony Mato, an oncologist and director of the CLL program at Memorial Sloan Kettering Cancer Center.
Historically, the standard treatment for CLL (after watching and waiting) was chemotherapy – which kills both cancer cells and healthy noncancerous cells and comes with serious side effects such as hair loss, appetite and weight loss, mouth sores and many others.
But treatment has changed dramatically since 2014, when the FDA began approving new medications to treat CLL called targeted therapies – pills that take aim only at specific molecules involved with cancer cell division and survival. Examples include venetoclax (Venclexta) and ibrutinib (Imbruvica).
Mato says the drugs have been so effective and well tolerated by patients with chronic lymphocytic leukemia that their quality of life has improved and chemotherapy use has greatly declined. “It’s a radical change, like night and day. As soon as the targeted medications became available, people started doing better,” he notes.
“These drugs work rapidly,” Jain adds. “Within a few weeks, patients feel better. Lymph nodes shrink in days to weeks. You see a remarkable improvement for patients even one week later.”
Targeted therapies aren’t without side effects. For example, Mato says up to 10% of patients taking ibrutinib experience irregular heartbeat, rash and bleeding. “But if one medication isn’t right for you, you can switch to another, and the odds are you’ll do quite well,” he says.
Beyond targeted therapies, other treatments are in the works, including several different types of therapies that use a person’s own immune system to fight cancer. These are known as immunotherapies. Examples include chimeric antigen receptor T cell therapy and checkpoint inhibitors – but both kinds of treatments are not yet FDA-approved to treat CLL.
When newer medications don’t work for patients, doctors have older treatments in their toolbox, such as chemotherapy, stem cell transplants and radiation.
Life expectancy after a diagnosis of chronic lymphocytic leukemia is improving. The five-year survival rate has gone from 67% in 1975 to 88% in 2015. Mato thinks the numbers are even better than that, but they are not yet reflected in research. “Most of the data come from models that haven’t yet accounted for the impact of novel agents,” he points out.
Evidence suggests that five-year survival rates on some targeted therapies, such as ibrutinib, can be as high as 90%.
According to UpToDate, a clinical database by and for doctors, about a third of people with chronic lymphocytic leukemia live for 10 to 20 years after a diagnosis. However, some people live for only a few years after diagnosis. Others live for up to 10 years.
But doctors are optimistic that the outlook for people with chronic lymphocytic leukemia is improving, thanks to new treatments.
“We have therapies available right now that can control the disease with pills for a long, long time,” Jain says.
“I think we’ll get to the point where the disease is not impacting survival,” Mato says. “Our goal is to allow people to live a normal life.”
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