Characteristics of breakthrough cancer pain and its influence on quality of life in an international cohort of patients with cancer

Objectives: Breakthrough cancer pain (BTP) represents a treatment challenge. Objectives were to examine the prevalence and characteristics of BTP in an international sample of patients with cancer, and to investigate the relationship between BTP and quality of life (QoL). Methods: This was an observational cross-sectional multicentre study. Participating patients completed self-report questionnaires on a touch-screen laptop computer, including the Brief Pain Inventory, Alberta Breakthrough Pain Assessment Tool (ABPAT) and European Organisation for Research and Treatment of Cancer 30-item Core Quality of Life Questionnaire (EORTC QLQ-C30). The study was performed in 17 centres in 8 countries and involved 4 languages (Norwegian, Italian, German and English). Results: Records from a convenience sample of 978 patients with advanced cancer were analysed; mean age was 62.2 years, 48.3% were women and 84.4% had metastatic disease. A total of 296 patients (30%) had no pain, defined as worst pain in the past 24 hours <1 on a 0-10 scale. Of the 682 patients with a pain score ≥1, 393 (58%) reported no BTP on the screening item, while 289 (30%) confirmed flare ups of BTP. Patients with BTP reported significantly higher pain intensity scores (<0.001) than patients without BTP; 57.1% of patients rated BTP at its worst as being severe: ≥7 on a 0-10 scale. Time from onset to peak intensity was <10 min for 42.9%, and average time to pain relief was 27.1 min. BTP was commonly triggered by medication wearing off (28%). Patients with BTP had significantly worse mean outcomes on 10 of 15 functional and symptom scales of the EORTC QLQ-C30 (<0.001). Severe pain intensity in the last week was a powerful predictor of BTP (OR 4.1) and poor QoL (OR 1.9). Conclusions: BTP is highly prevalent with prolonged episodes despite analgaesics, and has a pervasive impact on QoL. Patients reporting high pain intensity should be carefully evaluated for BTP and efficacy of analgaesic treatment, to provide optimal pain management and improve QoL.