Clinical Characteristics and Treatment Outcomes of Terminal Dyspnea: A Multicenter Cohort Study

<b><i>Context:</i></b> The clinical characteristics of terminal dyspnea, including opioid effects, adverse events, and outcome acquisition rates, remain largely unexplored. <b><i>Objectives:</i></b> To investigate the clinical characteristics of terminal dyspnea in patients with cancer starting regular systemic opioid therapy, classified by clinician-predicted prognosis (days, weeks, months). <b><i>Methods:</i></b> This secondary analysis of a multicenter, prospective, observational study included adult patients with cancer who began regular systemic opioid therapy for dyspnea at 12 palliative care sites in Japan. Patients were classified into three prognostic groups: days (1-14 days), weeks (15-56 days), and months (>56 days) according to clinician-predicted survival [CPS]. Dyspnea intensity (numerical rating scale [NRS], Integrated Palliative care Outcome Scale [IPOS]) was assessed every 24 hours for 3 days. Adverse events and outcome acquisition rates were also evaluated. <b><i>Results:</i></b> A total of 402 patients were enrolled (days: 186, weeks: 174, months: 42). NRS and IPOS scores significantly improved across all groups. At 72 hours, mean NRS decreased from 7.2 to 4.5 in the days group, 6.5 to 3.9 in the weeks group, and 5.8 to 3.2 in the months group (<i>p</i> < 0.001 for all). Mean IPOS showed similar reductions. Somnolence and delirium increased in the days group, whereas such trends were not observed in the other groups. NRS acquisition rates declined in the days group (73.1-55.2%) but remained high in the weeks and months groups. IPOS acquisition rates were consistently high across all groups. <b><i>Conclusion:</i></b> Opioids alleviate dyspnea in patients with cancer regardless of CPS, but persistent symptoms remain. In imminently dying patients, adverse events were common and NRS was often not assessable. Further research should be conducted to optimize the assessment and management of patients with terminal dyspnea.