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Post-Cancer Treatment Care

Cancer-Related Fatigue After Treatment:
Why It Happens and What Helps

Many cancer survivors expect their energy to return quickly once treatment ends. But fatigue—called cancer-related fatigue (CRF)—is one of the most common and frustrating effects of treatment. CRF is not the same as ordinary tiredness: it feels heavier, isn’t fully relieved by sleep, and can interfere with work, family, and daily life (National Cancer Institute, 2024). The good news is that it is real, common, and manageable with the right strategies.

How Common Is Cancer-Related Fatigue?

  • During treatment: Around 60–65% of patients experience significant fatigue (Al Maqbali et al., 2021).

  • After treatment: About half of survivors still report fatigue in the first 3 months (Al Maqbali et al., 2021).

  • Months to years later: About 1 in 3 survivors continue to feel fatigued a year or more after finishing treatment (Thong et al., 2025).

  • Long-term: Even 5–10 years later, fatigue persists in about 30% of survivors (Thong et al., 2025).

  • Severity: Roughly 1 in 4 survivors rate their fatigue as severe, but doctors often underestimate it (Kang et al., 2023).

Why Does Fatigue Happen After Cancer?:

CRF is multifactorial—it happens because of a mix of body changes, treatment effects, and lifestyle factors. Researchers believe several overlapping mechanisms are at play:

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1. Changes in the Immune System and Inflammation

Cancer treatments like chemotherapy, radiation, and immunotherapy can trigger inflammatory responses in the body. This increases chemicals called cytokines (such as IL-6 and TNF-α), which can affect the brain and muscles and are strongly linked with feelings of fatigue (Bower, 2019).

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2. Energy and Hormonal Regulation

Treatments may disrupt how the body:

  • Regulates stress hormones (like cortisol),

  • Produces energy at the cellular level (mitochondria), and

  • Balances the autonomic nervous system (the “automatic” system that regulates things like heart rate and energy).

When these systems are off balance, the body struggles to manage energy efficiently, leading to persistent fatigue (Bower, 2019).

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3. Other Health Conditions That Add to Fatigue

Some problems aren’t caused directly by cancer, but they make fatigue worse:

  • Anemia (low red blood cells)

  • Thyroid problems

  • Medication side effects (such as opioids or sedatives)

  • Chronic pain

  • Poor sleep or sleep apnea

  • Malnutrition or dehydration

The good news is that these are often treatable causes, so it’s important to get checked (National Cancer Institute, 2024).

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4. Emotional and Psychological Factors

Cancer affects not just the body, but also the mind. Anxiety, depression, stress, or even the challenge of “returning to normal life” after treatment can all amplify fatigue. Addressing emotional health—through counseling, support groups, or stress-management strategies—can meaningfully reduce fatigue (Mustian et al., 2017).

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5. Physical Deconditioning

Long periods of rest, treatment side effects, or reduced activity lead to muscle weakness and reduced stamina. This makes everyday activities (like climbing stairs or grocery shopping) feel harder, creating a cycle where low energy leads to less movement, which in turn causes more fatigue.

What Can Help Manage Cancer-Related Fatigue?:

Step 1: Get Checked

Ask your doctor to screen for treatable causes like anemia, thyroid problems, sleep disorders, or medication side effects (National Cancer Institute, 2024).

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Step 2: Move Your Body (Safely and Progressively)

Exercise is the most effective treatment for CRF—more effective than any medication (Mustian et al., 2017).

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The Role of Physical Therapy

A physical therapist can:

  • Assess your current strength, flexibility, and balance.

  • Create a personalized exercise program that accounts for surgery, radiation effects, neuropathy, lymphedema, or joint stiffness.

  • Teach safe techniques, monitor progress, and adapt the plan as your energy improves.

  • Provide guidance on pacing and activity management to avoid “boom and bust” cycles of overexertion and crash.

 

Sample Exercise Program (Start Small, Progress Gradually)

  • Walking Program (Aerobic Exercise):

    • Week 1–2: 10 minutes of walking, 4–5 days per week at a comfortable pace.

    • Week 3–4: Increase to 15–20 minutes.

    • Week 5–6: Aim for 25–30 minutes most days.

    • Goal: Build toward 150 minutes per week of moderate activity (Campbell et al., 2019).

  • Resistance Exercise (2 days per week):

    • Sit-to-Stand from a Chair (10–12 reps × 2 sets).

    • Wall Push-ups (10–12 reps × 2 sets).

    • Bicep Curls with Light Weights or Bands (10–12 reps × 2 sets).

    • Heel Raises (10–15 reps × 2 sets).

    • Progress gradually by adding resistance bands, small dumbbells, or increasing repetitions.

 

Tip: Always start with light intensity. You should feel gently challenged but not exhausted. If symptoms flare, scale back and progress more slowly.

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Step 3: Improve Sleep & Stress

  • Cognitive Behavioral Therapy for Insomnia (CBT-I) improves both sleep and fatigue (Greeley et al., 2025).

  • Relaxation techniques, yoga, tai chi, and mindfulness practices reduce stress and help restore energy (Bower et al., 2024).

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Step 4: Conserve Energy

  • Plan demanding activities during times you feel most energetic.

  • Take short, regular breaks instead of pushing until exhaustion.

  • Spread out chores and ask for help when needed (NCCN, 2024).

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Step 5: Other Options

  • Acupuncture or acupressure may help some survivors (Bower et al., 2024).

  • Supplements: Most do not show benefit, but American ginseng has shown some promise during treatment (Fabi et al., 2020). Always check with your care team.

  • Medications: Stimulants or antidepressants are not routinely recommended unless fatigue is tied to another condition (Bower et al., 2024). In advanced cancer, short courses of steroids may help for relief (Fabi et al., 2020).

Key takeaways:

Cancer-related fatigue is very common and can last long after treatment—but it is manageable. The best approach combines:

  • Medical checkups to rule out treatable causes

  • Safe, progressive exercise guided by a physical therapist

  • Better sleep and stress management

  • Practical energy-saving strategies

 

With time, persistence, and support, most survivors find their energy and quality of life improve.

Scientific References:

  • Al Maqbali, M., Al Sinani, M., Al Naamani, Z., & Al Badi, K. (2021). Prevalence of fatigue in patients with cancer: A systematic review and meta-analysis. Journal of Pain and Symptom Management, 61(1), 167–189.

  • Bower, J. E. (2019). The role of neuro-immune interactions in cancer-related fatigue: Biobehavioral risk factors and mechanisms. Cancer, 125(3), 353–364.

  • Bower, J. E., et al. (2024). Management of fatigue in adult survivors of cancer: ASCO–Society for Integrative Oncology Guideline Update. Journal of Clinical Oncology, 42(20), 2456–2487.

  • Campbell, K. L., Winters-Stone, K. M., et al. (2019). Exercise guidelines for cancer survivors. Medicine & Science in Sports & Exercise, 51(11), 2375–2390.

  • Fabi, A., et al. (2020). Cancer-related fatigue: ESMO Clinical Practice Guidelines. Annals of Oncology, 31(6), 713–723.

  • Greeley, K. M., et al. (2025). Mechanisms of CBT-I effects on fatigue in cancer survivors. Sleep, 48(6), zsaf014.

  • Kang, Y.-E., Yoon, J.-H., Park, N.-H., et al. (2023). Prevalence of cancer-related fatigue based on severity: A systematic review and meta-analysis. Scientific Reports, 13, 12815.

  • Mustian, K. M., Alfano, C. M., Heckler, C., et al. (2017). Comparison of pharmaceutical, psychological, and exercise treatments for cancer-related fatigue: A meta-analysis. JAMA Oncology, 3(7), 961–968.

  • National Cancer Institute. (2024). Fatigue (PDQ®)–Patient Version. https://www.cancer.gov/

  • NCCN Guidelines for Patients: Cancer-Related Fatigue (2024). National Comprehensive Cancer Network. https://www.nccn.org/

  • Thong, M. S. Y., Doege, D., Koch-Gallenkamp, L., et al. (2025). Fatigue in long-term cancer survivors: Prevalence, associated factors, and mortality. British Journal of Cancer.

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