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Questions and answers

Why are cycles repeated

Many patients ask: isn’t one cycle enough? There is a reason cycles are repeated.

Last updated: ~1 min read
Like waves: cycle after cycle
Figure 1.Like waves: cycle after cycle

01Short answer

Chemotherapy cannot kill all leukemia cells at once: each cycle removes a share of them. The break between cycles gives the healthy bone marrow time to recover. The next cycle then acts again on the leukemia cells that remain. This sequence (induction, consolidation and sometimes maintenance) is designed to lower the risk of relapse. The number of cycles and the schedule depend on the type and the response.

02Simple explanation

Each cycle removes a share of the leukemia cells.

The break lets healthy cells recover.

03Scientific explanation

Not all cells divide at the same time, and the drugs act mainly on dividing cells. Repeated cycles catch cells that start dividing later.

MRD results may be used to change the number and intensity of cycles.

04What happens in the body?

What the break is for

After a cycle blood counts fall, then the marrow recovers. The next cycle usually starts once neutrophils and platelets have risen to the required level.

The phases

Induction aims to reach remission, consolidation to strengthen it. Some types, such as ALL, also have a maintenance phase lasting years.

A calendar of cycles
Figure 2.A calendar of cycles

Delays

An infection or slow count recovery can postpone a cycle. This is for safety. Share your worries with the team.

Rest and recovery — Why are cycles repeated
Figure 3.Rest and recovery — Why are cycles repeated

05The cycle of treatment

Treatment and breaks alternate.

First cycle — Most leukemia cells are destroyed.1First cycleMost leukemia cells are destroyed.
Break and recovery — The healthy marrow recovers.2Break and recoveryThe healthy marrow recovers.
Next cycle — The remaining cells are targeted.3Next cycleThe remaining cells are targeted.
Response checked — Blood tests and a marrow examination.4Response checkedBlood tests and a marrow examination.
Lower relapse riskRepeats catch remaining cells.
A safe paceBreaks protect the body.

06Key points at a glance

TopicIn brief
What the break is forAfter a cycle blood counts fall, then the marrow recovers. The next cycle usually starts once neutrophils and platelets have risen to the required level.
The phasesInduction aims to reach remission, consolidation to strengthen it. Some types, such as ALL, also have a maintenance phase lasting years.
DelaysAn infection or slow count recovery can postpone a cycle. This is for safety. Share your worries with the team.

07Key terms

Cycle
A period of medicines followed by a break.
Consolidation
Cycles that strengthen remission.
Recovery
Blood counts rising again.

08Key points

  • One cycle does not kill all cells.
  • The break lets the marrow recover.
  • Cycles come in phases.
  • Delays are for safety.

09Frequently asked questions

How many cycles will I have?

It depends on the type, protocol and response; the doctor will explain the plan.

Can a cycle start earlier?

Starting before counts recover can be dangerous; the team decides.

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. How many cycles will I have?

  2. Can a cycle start earlier?

My questions

12Sources

  1. National Cancer Institute (NCI). Chemotherapy to Treat Cancer
  2. NHS. Chemotherapy
  3. National Cancer Institute (NCI). Adult Acute Myeloid Leukemia Treatment (PDQ®) – Patient Version
  4. National Cancer Institute (NCI). Adult Acute Lymphoblastic Leukemia Treatment (PDQ®) – Patient Version
  5. National Cancer Institute (NCI). What Is Cancer?
  6. American Cancer Society. Risk Factors for Acute Myeloid Leukemia (AML)
  7. Cancer.Net (ASCO). Talking With Family and Friends
  8. NHS. High temperature (fever) in adults
  9. NHS. Stem cell and bone marrow transplants
  10. NHS. How to wash your hands
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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