Fatigue (tiredness)
Cancer fatigue is a deep tiredness that rest does not fully fix. It is the most common side effect of cancer and its treatment.
Why it happens
Chemotherapy, radiation, immunotherapy, targeted drugs, hormone therapy, and surgery can all cause it. Anemia, poor sleep, pain, stress, and the cancer itself can add to it.
What helps
- Take a short walk most days. Gentle activity often helps fatigue more than extra rest.
- Plan your day. Do the most important tasks when you have the most energy.
- Keep naps short, about 20 to 30 minutes, so you can sleep at night.
- Let family and friends help with meals, rides, and chores.
- Drink fluids and eat small meals often to keep your energy steady.
- Keep a simple log of your energy levels to share with your care team.
Call your care team right away if you have
- You are so tired you cannot get out of bed or care for yourself.
- You feel dizzy, confused, or short of breath with the tiredness.
- Your fatigue gets much worse suddenly.
Questions to ask
- Could anemia, thyroid problems, or a medicine be adding to my tiredness?
- Would a physical therapy or exercise program be safe for me?
- Is there anything else we can check to explain my fatigue?
Medicines that can cause this
- Abemaciclib
- Abiraterone
- Acalabrutinib
- Adagrasib
- Alectinib
- Alpelisib
- Amivantamab
- Anastrozole
- Antithymocyte globulin (ATG)
- Apalutamide
- Apixaban
- Aprepitant and fosaprepitant
- Arsenic trioxide
- Asciminib
- Asparaginase (pegaspargase and others)
- Atezolizumab
- Axitinib
- Azacitidine
- Bendamustine
- Bortezomib
- Bosutinib
- Brentuximab vedotin
- Brigatinib
- Busulfan
- CAR T-cell therapy
- Cabazitaxel
- Cabozantinib
- Capecitabine
- Capivasertib
- Capmatinib
Sources
Quick answers
- What is fatigue during cancer treatment?
- Cancer fatigue is a deep tiredness that rest does not fully fix. It is the most common side effect of cancer and its treatment.
- Why does fatigue happen?
- Chemotherapy, radiation, immunotherapy, targeted drugs, hormone therapy, and surgery can all cause it. Anemia, poor sleep, pain, stress, and the cancer itself can add to it.
- What helps with fatigue?
- Take a short walk most days. Gentle activity often helps fatigue more than extra rest; Plan your day. Do the most important tasks when you have the most energy; Keep naps short, about 20 to 30 minutes, so you can sleep at night; Let family and friends help with meals, rides, and chores; Drink fluids and eat small meals often to keep your energy steady; Keep a simple log of your energy levels to share with your care team.
- When should I call my care team about fatigue?
- You are so tired you cannot get out of bed or care for yourself; You feel dizzy, confused, or short of breath with the tiredness; Your fatigue gets much worse suddenly.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.