Relationship between morphine rescue dose and respiratory safety during breakthrough cancer pain in lung cancer patients treated with high-dose opioids

To investigate the efficacy and safety of different morphine rescue doses for breakthrough cancer pain (BTcP) in lung cancer patients receiving high-dose opioid therapy.Between August 2023 and January 2025, 150 hospitalized patients with at least one documented BTcP episode were retrospectively assigned to three groups based on their initial rescue dose: a fixed 10 mg dose (Group A, n=47), 5% of their daily opioid dose (Group B, n=62), and 10% of their daily opioid dose (Group C, n=41).Pain intensity (numerical rating scale, NRS) and vital signs were recorded at baseline and up to 180 minutes after administration.The primary outcome was the proportion of patients with a ≥30% or ≥50% reduction in NRS at 60 minutes; safety outcomes included a ≥5% reduction in respiratory rate or oxygen saturation (SpO 2 ).The pain relief rates in groups B and C were significantly higher (≥30% reduction: 95.2% and 95.1%, respectively, compared to 68.1% in group A, P