Prevalence and incidence of chronic pain with or without neuropathic characteristics in patients with cancer
This prospective national multicenter study was carried out to estimate the prevalence and incidence of chronic pain with or without neuropathic characteristics in patients with cancer in France. All consecutive outpatients (n = 1885) seen over 2 weeks for cancer treatment in 12 oncology units were invited to participate in the study, and 1805 were included. Patients underwent a clinical examination during visit 1, and a questionnaire was completed to detect chronic pain (defined as daily pain for at least 3 months), and to characterize its intensity, location, and neuropathic characteristics (ie, DN4 score ≥4). The impact of pain on quality of life was assessed with the Brief Pain Inventory. Patients without pain at visit 1 were included in the incidence study and were seen at 3 and 6 months after visit 1. The overall prevalence of chronic pain was 28.2% (95% CI: 26.3-30.5), ranging from 22.5% to 35.4%, depending on the location of the primary tumor. Neuropathic characteristics were present in 20.9% of these patients, with a prevalence of 2.9% to 9.7%, depending on primary tumor location. Pain intensity and interference were higher in patients with neuropathic characteristics. In total, 1285 patients were included in the incidence study, 873 of whom were seen at least once, 3, or 6 months after the first visit. The incidence of chronic pain during the 6-month follow-up period ranged from 13% to 28%, depending on primary tumor location, and neuropathic characteristics were found in 19.9% of patients with chronic pain.