Breakthrough pain: characteristics and impact in patients with cancer pain

Few surveys have been performed to define the characteristics and impact of breakthrough pain in the cancer population. In this cross-sectional survey of inpatients with cancer, patients responded to a structured interview (t he Breakthrough Pain Questionnaire) designed to characterize breakthrough p ain, and also completed measures of pain and mood (Memorial Pain Assessment Card (MPAC)), pain-related interference in function (Brief Pain Inventory (BPI)), depressed mood (Beck Depression Inventory (BDI)), and anxiety (Beck Anxiety Inventory (BAI)). Of 178 eligible patients, 164 (92.2%) met the cr iteria for controlled background pain. The median age was 50.6 years (range 26 to 77 years), 52% were men, and 80.6% were Caucasian. Tumor diagnoses w ere mixed, 75% had metastatic disease, 65% had pain caused directly by the neoplasm, and a majority had mixed nociceptive-neuropathic pain. The median Karnofsky Performance Status score was 60 (range 40 to 90). Eighty-four (5 1.2%) patients had experienced breakthrough pain during the previous day. T he median number of episodes was six (range 1 to 60) and the median interva l from onset to peak was 3 min (range 1 s to 30 min). Although almost two-t hirds (61.7%) could identify precipitants (movement 20.4%; end-of-dose fail ure 13.2%), pain was unpredictable in a large majority (78.2%). Patients wi th breakthrough pain had more intense (P < 0.001) and more frequent (P < 0. 01) background pain than patients without breakthrough pain. Breakthrough p ain was also associated with greater pain-related functional impairment (di fference in mean BPI, P < 0.001), worse mood (mood VAS, P < 0.05; BDI, P < 0.001), and more anxiety (BAI, P < 0.001). Multivariate analysis confirmed that breakthrough pain independently contributed to impaired functioning an d psychological distress. These data confirm that cancer-related breakthrou gh pain is a prevalent and heterogeneous phenomenon. The presence of breakt hrough pain is a marker of a generally more severe pain syndrome, and is as sociated with both pain-related functional impairment and psychological dis tress. The findings suggest the need for further studies of breakthrough pa in and more effective therapeutic strategies. (C) 1999 International Associ ation for the Study of Pain. Published by Elsevier Science B.V.