Pain intensity, incident pain, pain localisation, and cancer diagnosis are important domains to include in an international cancer pain classification system.
The overall aim of the present study was to further develop an evidence-based platform for the content of an international cancer pain classification system. Data from a multicentre, observational longitudinal study of cancer patients were analysed. Analyses were carried out in 2 samples: (A) Cross-sectional data of patients on opioids at inclusion, and (B) patients just admitted to palliative care. Outcome measures in the models we investigated were pain on average, worst pain, and pain relief at inclusion, and at day 14, respectively. Uni- and multivariate regression models were applied to test the explicative power on pain outcomes of a series of known pain domains, including incident pain, psychological distress, neuropathic pain, pain localisation, sleep disturbances, total morphine equivalent daily dose (MEDD), and cancer diagnosis. In the 2 analyses, 1529 (A) and 352 (B) patients were included, respectively. Incident pain, pain localisation, MEDD, use of nonsteroidal antiinflammatory drugs, and sleep were associated with one or more of the pain outcomes in analysis A, while initial pain intensity, initial pain relief, incident pain, localisation of pain, cancer diagnosis, and age were predictors in the longitudinal analysis. Identified domains explained 16% to 24% of the variability of the pain outcome. Initial pain intensity emerged as the strongest predictor of pain outcome after 2 weeks, and incident pain was confirmed to be a relevant domain. The regression models explained only a minor part of the variability of pain outcomes.
aEuropean Palliative Care Research Centre, Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
bDepartment of Oncology, Trondheim University Hospital, Trondheim, Norway
cPalliative Care, Pain Therapy and Rehabilitation Unit, Fondazione IRCCS (Istituto di Ricovero e Cura a Carraterre Scientifico [Italian Research Hospital]), Istituto Nazionale Dei Tumori, Milano, Italy
dDepartment of Anesthesiology and Emergency Medicine, Intensive Care Unit, Trondheim University Hospital, Trondheim, Norway
eFaculty of Medicine, University of Oslo, Oslo, Norway
fRegional Center for Excellence in Palliative Care, Oslo University Hospital, Oslo, Norway
gScientific Directorate, IRCCS Arcispedale Santa Maria Nuova, Reggio-Emilia, Italy
hCenter for the Evaluation and Research on Pain, Department of Oncology, Instituto di Ricerche Farmacologiche ‘Mario Negri’, Milan, Italy
iDepartment of Circulation and Medical Imaging, Faculty of Medicine, Norwegian Univeristy of Science and Technology, Trondheim, Norway
*Corresponding author. Address: European Palliative Care Research Centre, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), 3. Floor Bevegelse, Trondheim University Hospital, Trondheim NO-7006, Norway. Tel.: +47 72 82 62 96; fax: +47 72 82 60 28.
1On behalf of the European Palliative Care Research Collaborative (EPCRC, Appendix A) and the Cancer Pain Outcome Research Study Group (CPOR-SG).
Submitted November 14, 2011; revised December 2, 2011; accepted December 9, 2011.