Epidemiology of Pain Among Patients with Solid Metastatic Cancer During the Last Year of Life

BACKGROUND: Despite medical advancements, pain is a major source of suffering at the end of life for patients with a solid metastatic cancer. We aimed to assess the trajectory of pain prevalence, severity, interference, and inadequacy of analgesia during the last year of life. METHODS: We analysed data from the last year of life of 345 decedents from a prospective cohort study of 600 patients with a solid metastatic cancer in Singapore. Patients were surveyed every 3 months and their pain outcomes (prevalence, severity, and interference) and inadequacy of analgesia were analysed. We used mixed-effects regressions to assess the association of pain outcomes with patients’ time from death, demographics, and planned or unplanned hospitalisations. RESULTS: Prevalence of pain was higher in the last 2 months (65%) compared to 11 to 12 months (41%) before death. Pain severity and interference scores (mean ± SD) were also higher in the last month (severity: 2.5±2.6; interference: 2.6±3.0) compared to 12 months before death (severity: 1.4±2.0; interference: 1.4±2.0). At any time during the last year of life, 38% of the patients were prescribed non-steroidal anti-inflammatory drugs, 11% were prescribed weak-opioids and 29% were prescribed strong opioids. These analgesics were prescribed through either oral, topical or injectable route. Pain outcomes were significantly worse (p-value<0.05) for younger patients, those with higher education, and more financial difficulties, while interference was higher after an unplanned hospitalisation in the last month. Females reported higher pain severity score during their last year of life compared to males. For patients reporting moderate to severe pain, inadequacy of analgesia was lower in the last 2 months (43%) compared to 11 to 12 months before death (83%). CONCLUSION: Findings highlight the need for greater attention in monitoring and treatment of pain even earlier in the disease trajectory, and increased attention to patients discharged from an unplanned hospitalisation.