How Do Chronic Lymphocytic Leukemia Patients Die?

CLL is usually a slow cancer of older adults, and many people live with it for years without it ever becoming what ends their life. When it does prove fatal, it rarely acts alone. It wears down the immune system and the bone marrow, so death usually comes through a complication such as infection, bleeding, or a second cancer. Newer treatments have reduced deaths from the leukemia itself, which shifts more of the risk toward problems that can be watched for and partly prevented.¹

The Main Causes of Death in CLL, by the Numbers

A nationwide Dutch study gives a good picture of what people with CLL die of:

The leukemia’s real share is higher than that first list suggests. When contributing causes listed on death records are included, CLL had a part in about 42% of deaths and infection in about 18%.⁷ Death records can also be inaccurate about the type of leukemia, so these shares are estimates.⁸

This is why “dying with CLL” and “dying from CLL” are different things. Many people never need treatment and live a normal span. Because CLL is typically diagnosed around age 70, heart disease and stroke compete as causes of death. A family member’s death certificate may say pneumonia even if CLL made that pneumonia possible. Asking the doctor which group a person is likely to fall into is a reasonable question.

Over the first ten years, the risk is spread fairly evenly. Among people followed from diagnosis, about 13 in 100 had died from CLL getting worse within 10 years.⁹ About 8 or 9 in 100 died from CLL-related complications like infection or a second cancer, and a similar share died from unrelated causes over the same period.¹⁰ A person’s own outlook can differ a lot from these averages, which mix slow and aggressive cases together.

When CLL Itself Becomes Fatal

Bone marrow failure is the main direct route. In about a quarter of people with CLL, blood counts drop at some point, and in most of those whose low counts come from CLL, the cause is the marrow being crowded out.¹¹ The body then can’t make enough red cells, platelets, or infection-fighting white cells. Once marrow failure sets in, median survival was about 4.4 years.¹² Low counts caused instead by the immune system attacking blood cells carried a much better outlook, about 9 years.¹³

Low counts in CLL can come from the leukemia crowding the marrow, the immune system attacking blood cells, an enlarged spleen trapping cells, or a side effect of treatment. These are treated differently, so a doctor usually looks for the cause first, using a blood-film review, markers of red cell destruction, and sometimes a bone marrow biopsy.

Advancing CLL tends to show up in everyday ways. Growing tiredness and breathlessness come from anemia. Easy bruising or nosebleeds point to low platelets. Swollen glands and a full feeling under the left ribs can mean an enlarged spleen. Night sweats, fevers, and weight loss without a clear cause are also common.

Some CLL is harder to control from the start. Changes in a gene called TP53, found on a blood test, are linked to shorter survival, and losing both copies carries the worst outlook.¹⁴ CLL can also return after treatment, and in some people it no longer responds.¹⁵

When treatment stops working, doctors usually switch to a drug from a different class. Transfusions can support low counts for a time, and clinical trials may be an option at major centres. Asking about TP53 testing before starting treatment helps choose the right drugs.

Why Infections Are So Dangerous With CLL

The immune system is weakened at several levels. Up to 85% of people with CLL develop low antibody levels, which a blood test may report as hypogammaglobulinemia.¹⁶ Antibodies are the proteins that tag bacteria for destruction, so these people are especially prone to bacterial infections such as pneumonia. CLL cells also disrupt the T cells that coordinate immune defence, even when T-cell counts look normal.¹⁷

Neutrophils add to the problem. These white cells are first responders against bacteria, and they can run low when CLL crowds the marrow or when treatment suppresses it. Your blood count report may flag this as neutropenia. With low neutrophils on top of low antibody levels, bacteria meet fewer defences at once, which is a reason to take any fever especially seriously. Some treatments lower these cells further, so the care team may check counts regularly during therapy.

Vaccines often produce a weak response in CLL.¹⁸ Being vaccinated doesn’t guarantee protection, though it still helps, and vaccines for household members add a layer. Early in the pandemic, about 4 in 5 people with CLL who caught COVID-19 became seriously ill.¹⁹ Death rates then fell from about 25% early on to about 13% in the Omicron period as vaccines and treatments arrived.²⁰

Several steps lower the risk. Flu, pneumonia, COVID-19 and shingles vaccines are worth having, avoiding live vaccines unless the care team approves. Call the care team promptly for a fever over 38°C. Fever can be mild or absent in older people, and confusion or sudden weakness can be the first sign. After repeated infections, ask whether antibody replacement infusions are an option. If you’re exposed to COVID-19 or flu, ask about early antiviral drugs.

Richter Transformation and Other Cancers

Richter transformation is when CLL changes into a fast-growing lymphoma. It often shows as rapidly swelling glands, fevers, and sudden weight loss. Outlook is poor, with median survival about a year.²¹

Telling it apart from ordinary CLL growth can be hard. One gland growing much faster than the others is a clue, as are high fevers without infection. A PET scan can point to the area most likely affected, but a biopsy is needed to confirm it.

People with CLL develop other cancers about twice as often as the general population, and the higher risk lasts at least 9 years.²² Skin cancer is the most common, followed by prostate and breast cancer.²³ Skin cancers, including melanoma, had the highest excess death rate of all causes.²⁴ Deaths from bowel and lung cancer were also raised.²⁵

Several things explain this. The immune system normally helps spot and clear abnormal cells, and CLL weakens that surveillance, especially for skin cancers. Some treatments used for CLL in the past may also add to the risk of other cancers later. Older age and shared exposures such as smoking and sun contribute too.

Screening is the practical response. Yearly full skin checks with a dermatologist make sense, and any new or changing mole or sore that won’t heal should be reported. Keep up bowel, breast and prostate screening for your age. Sunscreen helps, and tanning is best avoided.

Bleeding and Autoimmune Problems

Bleeding can come from too few platelets, from the immune system destroying them, from an enlarged spleen trapping them, or from platelets that don’t work well.²⁶ Ibrutinib adds to the risk by blocking platelet function, especially when the platelet count is also low.²⁷ Combining ibrutinib with blood thinners and anti-platelet drugs can be dangerous; one fatal bleed occurred on ibrutinib, apixaban and clopidogrel together.²⁸

Many older people with CLL also have atrial fibrillation or other conditions where blood thinners prevent strokes, so stopping them is not simple. Stopping raises clot and stroke risk, while continuing raises bleeding risk, especially with ibrutinib and low platelets. The cardiologist and haematologist should make this decision together with the patient.

The immune system can also attack red cells. This is the most common autoimmune problem in CLL; doctors may call it autoimmune hemolytic anemia.²⁹ It occurs in about 10 to 20% of people with progressing CLL.³⁰ It can be life-threatening, though it usually responds to treatment and doesn’t worsen the overall outlook.³¹

Some signs need urgent attention: black stools, vomiting blood, or a severe sudden headache; yellowing skin or dark urine, which suggest red cell destruction; and sudden breathlessness from a rapidly falling blood count.

It helps to tell every doctor and dentist if you take a BTK inhibitor such as ibrutinib. Ask before taking aspirin, ibuprofen, fish oil or blood thinners. Treatment is often paused around surgery.

Heart and Other Risks From Treatment

Ibrutinib causes atrial fibrillation, an irregular heartbeat, in up to 38% of patients.³² Newer drugs in the same family, like acalabrutinib and zanubrutinib, still carry some heart risk.³³ Dangerous heart rhythms or sudden cardiac death are rare, about 6 to 8 per 1,000 patients per year on ibrutinib.³⁴ But people with frequent atrial fibrillation on these drugs had about three times the risk of major heart events and death.³⁵

Protecting the heart starts before treatment, with blood pressure and an ECG check. Report palpitations, dizziness, or fainting at once, and ask whether a cardiologist should follow you. A drug switch is often possible if heart problems appear.

The overall picture has shifted. Since newer drugs arrived, the risk of dying from CLL fell by about 30%, but there was a trend toward more heart-related deaths.³⁶

Venetoclax works differently. It can kill cancer cells so fast that their contents flood the blood, which can harm the kidneys and heart.³⁷ With slow dose increases, fluids, and blood tests, serious cases have become uncommon.³⁸

Who Faces Higher Risk

Other health problems drive many deaths. Having more health conditions at diagnosis raised the risk of dying from causes other than CLL.³⁹ Other illnesses were also linked to more deaths from infection and heart disease.⁴⁰

Age matters on its own. The average age at diagnosis is around 70, so many people already face the ordinary risks of heart disease, stroke, and other cancers. Older age also makes it harder to tolerate infections and some treatments. That doesn’t take treatment off the table; doctors choose gentler options and adjust doses to fit the person’s overall fitness. Functional ability, such as whether someone can manage daily tasks, often guides care as much as their birth date.

Where and how people live matters too. In England, people in the most deprived areas had about 40% higher risk of death.⁴¹ In the US, Black patients and those with lower income had shorter survival.⁴²

Some risks can be lowered. Keep a regular family doctor alongside the specialist, stop smoking, and stay active. If cost or distance makes appointments hard, ask about financial or travel help.

End-of-Life Care and What Helps

Hospice is care focused on comfort in the final phase of life, and it often comes late. About 56% of older Americans dying of blood cancers used hospice, and the typical stay was only 9 days.⁴³ People who needed regular blood transfusions had even shorter stays.⁴⁴ Since many hospices don’t give transfusions, transfusion needs can delay referral. Hospice use was linked to far fewer deaths in hospital and fewer intensive care stays in the final month.⁴⁵

Palliative care is different. It focuses on comfort and quality of life and can be given at any stage, including alongside active CLL treatment. A person can see a palliative team for fatigue, pain, or breathlessness years before they would need hospice, and starting early does not mean giving up on treatment. Hospice is for the point when treatment aimed at controlling the disease is no longer the goal.

It may be time to talk about hospice when treatments have stopped working or side effects outweigh benefits, when infections keep sending the person to hospital, or when reliance on transfusions is growing. To raise the subject, ask the doctor what they expect in the coming months, ask whether palliative care can start alongside treatment, and ask which local hospices allow transfusions.