Post-exertional Malaise In People With Chronic Cancer-related Fatigue

Abstract

PURPOSE: Cancer-related fatigue (CRF) is a distressing and persistent sense of tiredness or exhaustion that interferes with usual functioning. Chronic CRF continues long after the completion of curative cancer treatment. Post-exertional malaise (PEM) is the worsening of symptoms after even minor physical, mental or emotional exertion. PEM has been inadequately investigated in people with chronic CRF. The purpose of this study was to identify and describe self-reported incidences of PEM in a group of people with chronic CRF. METHODS: Participants (n=18) were eligible if they scored ≤34 on the Functional Assessment of Chronic Illness Therapy - Fatigue scale, had a cancer-related onset of fatigue and ≥3 months since completion of curative cancer treatment. Participants completed a brief questionnaire to assess PEM over a 6-month time frame (the DePaul Symptom Questionnaire - Post-Exertional Malaise; DSQ-PEM). In addition, a maximal exercise test was used to investigate self-reported symptoms (via an open-ended questionnaire) after strenuous physical exertion. RESULTS: We found preliminary evidence that a minority of people (5/18 in this sample) with chronic CRF may experience PEM. According to the DSQ-PEM, 4 participants indicated that they experienced all symptoms of a frequency (ranging from “at least half of the time” to “all the time”) and severity (ranging from “moderate” to “very severe”) that were indicative of PEM. Although the majority of people experienced some worsening of fatigue after maximal exercise (12/18), content analysis identified 5 people who experienced prolonged adverse consequences, including the need to reduce daily activities to account for increased fatigue, flu-like symptoms, mood disturbances and/or issues with memory/concentration. CONCLUSION: While only a minority of people with chronic CRF may experience PEM, exercise specialists and health care professionals working with people with chronic CRF must be aware that PEM may be an issue. Symptom exacerbation after exercise should be monitored, and exercise should be prescribed to limit the potential for harm. Supported by Canadian Cancer Society grant #704208-1.