Cancer-Related Fatigue

By Lucas Tims, ND, FABNO

Fatigue is a common problem in cancer patients, both among those undergoing active treatment and in survivors. Some reports show that as many as 90% of cancer patients struggle with fatigue at some point in their journey and a prevalence of up to 45% in cancer survivors. The fatigue that comes with cancer, called cancer-related fatigue (CRF), is different from the fatigue of daily life. CRF causes disruption in all aspects of quality of life, and may be a risk factor for reduced survival.

By definition, CRF is a distressing, persistent, subjective sense of physical, emotional, and/or cognitive tiredness or exhaustion related to cancer or cancer treatment, that is not proportional to recent activity, and interferes with usual functioning. More and more, cancer centers are relying on integrative medicine practitioners to help manage this complex condition with complementary and alternative (CAM) therapies, as these have been shown to be the most promising interventions available at this time.

What Causes It?

While the causes of CRF are not fully understood, it is generally thought to be a multifactorial condition and component of a symptom complex which may include depression, anxiety, and sleep disorders.

With CRF, sometimes there are measurable factors involved, such as anemia, nutritional deficiencies or hormonal imbalances. However, more often there are intangibles that may contribute to CRF, such as pain, stress, poor sleep patterns, deconditioning, and medication side effects. On top of all that, there is the fatigue that can be caused by cancer itself, as well as cancer treatments such as surgery, chemotherapy and radiation.

Given the complexity of the problem and the lack of objective measurement of what is primarily a subjective symptom, interventional trials have been somewhat limited.

What Can be Done?

Despite the lack of a universal objective measurement for CRF, research into effective interventions has continued to build and better inform clinicians on how to mitigate this highly prevalent condition. Several evidence-based therapies have been identified to potentially help improve CRF.  Let’s take a look at some of these:

  • Ginseng – This traditional Chinese Medicine herb has long been used as a natural energy booster. In a large study led by Mayo Clinic, high doses of the American ginseng (Panax quinquefolius) given over two months was effective at reducing CRF1. Ginseng’s improvement of fatigue is likely due to its known mechanisms of decreasing inflammation and regulating cortisol levels.
  • IV Vitamin C – A 2018 review of several human trials concluded that intravenous ascorbic acid (vitamin C) up to 25g can improve several quality of life measures including CRF2. Of note, most of these trials have shown this effect in patients undergoing concomitant chemotherapy treatments.
  • Mistletoe – European mistletoe (Viscum album) extracts have an extensive history of use and clinical evidence as a safe and effective adjunctive cancer treatment to help with quality of life measures, including CRF. Although it is used across all tumor types, gynecologic and breast cancer patients have shown particular improvement in fatigue with mistletoe use3.
  • Acupuncture – More established as a tool to treat pain and nausea in cancer patients, recent studies have also shown this versatile modality to be quite beneficial for CRF4.
  • Exercise – Aerobic exercise, with its myriad health benefits, has been clearly shown to improve CRF, particularly in survivors. The American Cancer Society recommends that adult cancer survivors get at least 150 minutes of moderate intensity or 75 minutes of vigorous activity each week (or a combination of the two). This intervention not only helps with CRF but also with reduction of cancer recurrence.
  • Sleep – The majority of studies that have assessed both sleep and fatigue in patients with cancer provide evidence supporting a strong correlation between CRF and various sleep parameters. It’s clear that the quality and duration of sleep, or lack thereof, reciprocate with CRF. Improving sleep hygiene is crucial and often times the first place to start. Beyond that, a trial of a natural sleep aid, such as melatonin, may be enough to tip the scales in favor of improved sleep.
  • Tai Chi – The traditional Chinese health-promoting exercise, often done in groups, has been shown to have many positive effects in cancer patients. A meta-analysis investigating the effectiveness of Tai Chi on CRF concluded that the practice leads to short-term ameliorative effects that are actually superior to rigorous physical exercise and psychological support5. The best effects were shown in patients with breast and lung cancers.


CRF is one of the most distressing cancer-related symptoms and requires a clinician or team of clinicians to look at many underlying causes and interrelated conditions. Cancer patients are best served by working with an integrative practitioner who has knowledge of all of the CAM therapies indicated for CRF, and who continues to look at all potential underlying causes, even as the patient moves into long-term survivorship. As the understanding of cancer and its treatments evolves rapidly, so will our understanding of CRF and how to best manage it.


  1. PMID: 23853057
  2. PMID: 29719430
  3. PMID: 19519890
  4. PMID 29128952
  5. PMID: 29564620