1. Post-Exertional Malaise in People with Cancer Related Fatigue
Samuel Tin Yan Yeung1; Rosie Twomey PhD1; S. Nicole Culos-Reed PhD1,2,3
1Faculty of Kinesiology, University of Calgary, AB, 2Department of Oncology, Cumming School of Medicine, University of Calgary & Tom Baker Cancer Centre; 3Department of Psychosocial Resources, Tom Baker Cancer Centre, AB, Canada
Despite worsening of symptoms, exercise can still be beneficial psychosocially
It is important for clinicians to be vigilant and cautious in considering individual effects of physical activity on fatigue symptoms.
Results
Discussion
Introduction
Part A: Maximal Exercise Test
Part B: DSQ-PEM
Part C: Systematic Review
Preliminary evidence (Part A and B) suggests that some people with CRF may experience worsening of symptoms after strenuous activity i.e. PEM.
Clinical trials in people with CRF do not adequately monitor or report fatigue during a physical activity intervention (Part C).
In conclusion, exercise is likely to be beneficial for most people with CRF after cancer treatment, but PEM should be recognised as a potential issue.
Cancer-related fatigue (CRF) includes physical, mental and emotional exhaustion resulting in interference of activities of daily living, caused by cancer or the treatment of cancer1.
Post-exertional malaise (PEM) is a hallmark symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and is defined as disproportionate worsening of fatigue after minimal exertion2.
Exercise has been established as a safe and efficacious way to manage cancer treatment symptoms, and has been shown to elicit many physical, cognitive and emotional benefits3.
Due to the similarities in symptoms between ME/CFS and chronic CRF, clinicians may hesitate to prescribe exercise for people with chronic CRF because of the potentially harmful effects of PEM.
This study aims to understand the effect of exercise on people with CRF and examine PEM in this population. 
Of the 14 participants who completed the open-ended questionnaire, 9 reported a worsening of fatigue after the exercise test.
Four of the 14 participants reported the need to change their routine to accommodate for the fatigue
Five people reported that the fatigue resulted in a reduction in their daily activities.
Table 1. Participant Baseline Characteristics
Characteristic Variables
Age, mean (SD)
53 (13)
Sex
Male, n (%)
4 (26.7)
Female, n (%)
11 (73.3)
Height (cm), mean (SD)
169 (11)
Body Mass (kg), mean (SD)
80.3 (16.3)
Fatigue Score (FACIT-F), mean (SD)
23 (7)
Months Since Treatment (SD)
21 (16)
It is recommended that those working with CRF populations be cautious and diligent in the way that exercise is used as a method of improving quality of life
We also recommend that researchers monitor fatigue, provide supervision and regularly reassess an exercise program for people with CRF.
Thirteen participants completed the DSQ-PEM questionnaire.
Seven of the 13 have at least one of the symptoms of PEM.
Methods
Part A: Maximal Exercise Test
Participants
Males and females aged 18-75
Completed treatment (≥3 months and ≤5 years)
Score  ≤34 on the Functional Assessment of Chronic Illness Therapy Fatigue Scale (FACIT-F)4.
Procedures
Participants completed a maximal exercise test
Participants completed an open-ended questionnaire 96 h after the test, to get qualitative feedback on symptoms.
Data Analysis 
The questionnaires were analyzed using content analysis5.
Part B: DSQ-PEM
Participants from Part A completed a questionnaire (the DSQ-PEM) to measure frequency, severity and duration of PEM over a 6-month period.
Responses were reviewed for criteria related to PEM.
Part C: Systematic Review
A systematic review of randomized trials was conducted (see Figure 2) for the purpose of a narrative synthesis.
Studies were eligible if:
Fatigue was an eligibility criterion
A physical activity intervention was included
The intervention was delivered after cancer treatment
The search was deduplicated, screened and then specific methodological characteristics were extracted.
Subheading 3
Figure 1. DSQ-PEM Scoring Responses
Three of these 7 people experience a frequency and severity above 2 for all 5 symptoms, indicating PEM.
Table 2. Systematic Review Study Findings
Studies
(n = 13)
Fatigue Scale(s) Used 12
Fatigue Monitoring During Intervention
Monitored, n (%)
2 (15.4%)
Not Monitored, n (%)
11 (84.6%)
Supervision
Supervised, n (%)
6 (46.2%)
Non-supervised, n (%)
7 (53.8%)
Adverse Events
Reported, n (%)
5 (38.5)
Not Reported, n (%)
8 (61.5)
Compliance
3 (23.1)
10 (76.9)
Improvement in Fatigue
Prespecified, n (%)
Not Prespecified, n (%)
References
[1] Berger, A. M., Mooney, K., Alvarez-Perez, A., Breitbart, W. S., Carpenter, K. M., Cella, D., … National comprehensive cancer network. (2015). Cancer-Related Fatigue, Version Journal of the National Comprehensive Cancer Network: JNCCN, 13(8), 1012–1039.
[2] Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. (2019, August 8). Retrieved August 12, 2019, from
[3] Cormie, P., Atkinson, M., Bucci, L., Cust, A., Eakin, E., Hayes, S., … Adams, D. (2018). Clinical Oncology Society of Australia position statement on exercise in cancer care. The Medical Journal of Australia, 209(4), 184–187.
[4] Van Belle, S., Paridaens, R., Evers, G., Kerger, J., Bron, D., Foubert, J., … Rosillon, D. (2005). Comparison of proposed diagnostic criteria with FACT-F and VAS for cancer-related fatigue: Proposal for use as a screening tool. Supportive Care in Cancer: Official Journal of the Multinational Association of Supportive Care in Cancer, 13(4), 246–254.
[5] Hsieh, H.-F., & Shannon, S. E. (2005). Three Approaches to Qualitative Content Analysis. Qualitative Health Research, 15(9), 1277–
Figure 2. PRISMA Flow Diagram