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Medical glossary

CLL: chronic lymphocytic leukaemia

CLL is a slow leukaemia in which mature-looking but poorly working B lymphocytes build up. It mostly affects older people.

Last updated: ~1 min read
A blood smear in chronic lymphocytic leukaemia with many small dark lymphocytes and smudged smear cells among red cells
Figure 1.CLL: many small lymphocytes and smear cells

01Short answer

In many people CLL causes no symptoms for years and needs only monitoring (“active monitoring” or “watch and wait”); this is not refusing treatment but the right strategy. Treatment starts when symptoms appear or counts worsen; targeted medicines (BTK and BCL-2 inhibitors) play a central role. Genetic markers (TP53, IGHV) are considered when choosing. People with CLL are more prone to infections.

02Simple explanation

B lymphocytes.

Slow.

Active monitoring.

Targeted medicines.

03Scientific explanation

NCI: CLL is a slow cancer with many abnormal lymphocytes in the blood and bone marrow.

The NCI Dictionary explains cancer terms in plain language; check the exact meaning for your situation with your doctor.

04What happens in the body?

Active monitoring

Regular check-ups, with treatment when needed.

A watchful eye
Figure 2.A watchful eye — CLL: chronic lymphocytic leukaemia

Infections

Discuss a vaccination plan with your doctor.

A calm path
Figure 3.A calm path — CLL: chronic lymphocytic leukaemia

Where you will see this word

In test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.

Ask your doctor

The general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

05From an unfamiliar word to a clear answer: four steps

Write it down, look it up, prepare a question, ask.

Write it down — From a result or a conversation.1Write it downFrom a result or a conversation.
Look it up — Learn the plain meaning.2Look it upLearn the plain meaning.
Prepare a question — What does this mean for me?3Prepare a questionWhat does this mean for me?
Ask — Your doctor gives the personal explanation.4AskYour doctor gives the personal explanation.
UnderstandingResults feel less frightening.
ConversationA shared language with your doctor.
SafetyNot drawing conclusions alone.

06Key points at a glance

TopicIn brief
Active monitoringRegular check-ups, with treatment when needed.
InfectionsDiscuss a vaccination plan with your doctor.
Where you will see this wordIn test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.
Ask your doctorThe general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

07Key terms

Lymphocyte
An immune white blood cell.
Active monitoring
A strategy of observation without treatment.
Term
A word with a precise medical meaning.
Reference range
The range a laboratory considers normal.

08Key points

  • Learn.
  • Ask your doctor.
  • Write it down.
  • Write the word down.
  • Ask what it means.

09Frequently asked questions

Why am I not being treated?

Early treatment does not always help; monitoring is safe.

When will treatment start?

When symptoms or counts change.

This word is in my results: should I worry?

The word itself does not mean a serious or mild condition; get the explanation from your doctor.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Why am I not being treated?

  2. When will treatment start?

  3. This word is in my results: should I worry?

My questions

12Sources

  1. National Cancer Institute. NCI Dictionary of Cancer Terms: chronic lymphocytic leukemia
  2. National Cancer Institute. Chronic Lymphocytic Leukemia Treatment (PDQ®) – Patient Version
  3. National Cancer Institute. NCI Dictionary of Cancer Terms
  4. National Cancer Institute. Leukemia
  5. National Cancer Institute. NCI Dictionary of Cancer Terms: chronic myelogenous leukemia
  6. National Cancer Institute. NCI Dictionary of Cancer Terms: human leukocyte antigen
  7. National Cancer Institute. NCI Dictionary of Cancer Terms: CAR T-cell therapy
  8. National Cancer Institute. NCI Dictionary of Cancer Terms: petechiae
  9. National Cancer Institute. NCI Dictionary of Cancer Terms: gene
  10. MedlinePlus Genetics. Help Me Understand Genetics: The basics
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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