Background: Dyspnea is a very distressing symptom present in the vast majority of patients with advanced cancer. There are limited data on the characteristics and correlates of dyspnea in this population. The purpose of this study was to characterize dyspnea, explore the differences between breakthrough and continuous presentations, and to determine factors associated with its intensity.
Methods: Prospective observational study among 70 patients with dyspnea referred to a palliative care service. Dyspnea was assessed using the Edmonton Symptom Assessment System (ESAS, 0-10) and the Oxygen Cost Diagram (OCD). Oximetry, pulmonary function tests, Hospital Anxiety and Depression Scale (HADS), and a detailed systematic evaluation of daily characteristics of dyspnea were performed. Other symptoms were recorded using the ESAS.
Results: Of 30 patients, 70 (43%) were female, median age was 58 (range, 28-87), and the most frequent cancer diagnosis were lung (31/70; 44%) and urologic (15/70; 21%). Constant dyspnea occurred in 27 of 70 (39%) patients, with 14 of 70 (20%) presenting breakthrough episodes. Breakthrough-only dyspnea occurred in 43 of 70 (61%). The majority of patients with breakthrough episodes (39/57; 68%) presented fewer than 5 episodes daily, most frequently lasting for less than 10 minutes (50/57; 88%). In univariate analyses ESAS dyspnea was associated with fatigue (p < 0.0001), sleep (p = 0.002), anxiety (p = 0.006), depression (p = 0.01), sensation of well-being (p = 0.03), and with OCD (p = 0.001). In multivariate analysis, ESAS dyspnea was associated with fatigue (p = 0.001), forced expiratory volume (p = 0.004), pain (p = 0.01), and depression (p = 0.03). Dyspnea intensity significantly interfered with activities (general activity, p = 0.01, mood, p = 0.02, walking ability, p = 0.04, normal work p = 0.04, and enjoyment of life, p = 0.01).
Conclusion: Dyspnea in patients with advanced cancer more frequently had breakthrough characteristics, was of very short duration, and interfered with daily activities.