How successful are we in relieving terminal dyspnea in cancer patients? A real-world multicenter prospective observational study

Purpose Parenteral morphine is widely used for dyspnea of imminently dying cancer patients, but the outcomes to expect over time remain largely unknown. We examined outcomes after the administration of parenteral morphine infusion over 48 h in cancer patients with a poor performance status. Methods This was a multicenter prospective observational study. Inclusion criteria were metastatic/locally advanced cancer, ECOG performance status = 3–4, a dyspnea intensity ≥ 2 on a Support Team Assessment Schedule, Japanese version (STAS-J), and receiving specialized palliative care. After initiating parenteral morphine infusion, we measured dyspnea STAS-J as well as Memorial Delirium Assessment Scale (MDAS), item 9, and Communication Capacity Scale (CCS), item 4, every 6 h over 48 h. Results We enrolled 167 patients (median survival = 4 days). The mean age was 70 years, 80 patients (48%) had lung cancer, and 109 (65%) had lung metastases. The mean STAS-J scores decreased from 3.1 (95% confidence interval (CI) = 3.0–3.2) at the baseline to 2.1 (95%CI = 1.9–2.2) at 6 h, and remained 1.6–1.8 over 12–48 h. The proportion of patients with dyspnea relief (STAS-J ≤ 1) increased to 39% at 6 h, and ranged between 49 and 61% over 12–48 h. In contrast, up to 6.6 and 20% of patients showed hyperactive delirium (MDAS item 9 ≥ 2) and an inability to communicate (CCS item 4 = 3), respectively, over 48 h. Conclusions Overall, terminal dyspnea was relatively well controlled with parenteral morphine, though a significant number of patients continued to suffer from dyspnea. Future efforts are needed to improve outcomes following standardized dyspnea treatment using patient-reported outcomes for imminently dying patients.