Edmonton Classification System For Cancer Pain Research Articles

The Edmonton Classification System for Cancer Pain in Patients with Bone Metastasis: a descriptive cohort study

PurposeWe describe the prevalence of the Edmonton Classification System for Cancer Pain (ECS-CP) features in patients with bone metastasis and cancer-induced bone pain (CIBP) and the relationship between ECS-CP features, pain intensity, and opioid consumption.MethodsWe assessed ECS-CP features and recoded pain mechanisms and opioid use in adult patients with bone metastasis. Validated measures were used to assess pain intensity, incident pain, psychological distress, addictive behavior, and cognition.ResultsAmong 147 eligible patients, 95.2% completed the assessment. Mean participant age was 73.2 years, the majority female (52.1%) with breast cancer occurring most commonly (25.7%). One or more ECS-CP features were present in 96.4% and CIBP in 75.7% of patients. The median average and worst pain scores were 3 and 6, respectively. Neuropathic pain was the most prevalent pain mechanism (45.0%) and was associated with breakthrough pain frequency (p=0.014). Three-quarters had incident pain, which was strongly associated with a higher average and worst pain scores (3.5 and 7, p<0.001 for both), background oral morphine equivalent daily dose (26.7mg, p=0.005), and frequency of daily breakthrough analgesia (1.7 doses/day, p=0.007). Psychological distress (n=90, 64.3%) was associated with a significantly higher average pain score (4, p=0.009) and a slightly higher worst pain score (7, p=0.054). Addictive behaviour and cognitive dysfunction were relatively uncommon (18.6% and 12.9%, respectively).ConclusionThere is a need to promote standardized assessment and classification of pain syndromes such as CIBP. The ECS-CP may allow us to consider CIBP in a systematic manner and develop personalized pain interventions appropriate to the pain profile.Trial registrationRetrospectively registered in ANZCTR ACTRN12622000853741 (16/06/2022)

Edmonton Classification System for Cancer Pain: Comparison of Pain Classification Features and Pain Intensity across Diverse Palliative Care Settings in Canada.

Background: The goal of the Edmonton Classification System for Cancer Pain (ECS-CP) is to create an international classification system for cancer pain. Previous studies reinforce the need for standardized training to ensure consistency across assessors. There is no universally accepted classification for neuropathic pain. Objectives: Our primary objective was to describe the prevalence of ECS-CP features in a diverse sample of advanced cancer patients, using assessors with standardized training. The secondary objectives were to: (1) determine the prevalence of neuropathic pain using the Neuropathic Pain Special Interest Group (NeuPSIG) criteria and (2) examine the relationship between specific predictors: ECS-CP features, age, Palliative Performance Scale, Morphine Equivalent Daily Dose (MEDD), setting, and pain intensity; and neuropathic pain. Methods: A total of 1050 adult patients with advanced cancer were recruited from 11 Canadian sites. A clinician completed the ECS-CP and NeuPSIG criteria, and collected additional information including demographics and pain intensity (now). All assessors received standardized training. Results: Of 1050 evaluable patients, 910 (87%) had cancer pain: nociceptive (n = 626; 68.8%); neuropathic (n = 227; 24.9%); incident (n = 329; 36.2%); psychological distress (n = 209; 23%); addictive behavior (n = 51; 5.6%); and normal cognition (n = 639; 70.2%). The frequencies of ECS-CP features and pain intensity scores varied across sites and settings, with more acute settings having higher frequencies of complex pain features. The overall frequency of neuropathic pain was 24.9%, ranging from 11% (hospices) to 34.2% (palliative outpatient clinic) across settings. Multivariate logistic regression analysis revealed that age <60 years, MEDD ≥19 mg, pain intensity ≥7/10, and incident pain were significant independent predictors of neuropathic pain (p < 0.05). Conclusion: The ECS-CP was able to detect salient pain features across settings. Furthermore, the frequencies of neuropathic pain utilizing the NeuPSIG criteria fits within the lower-end of literature estimates (13%-40%). Further research is warranted to validate the NeuPSIG criteria in cancer pain.

Pain flare, complexity and analgesia in bone oligometastases treated with stereotactic body radiation therapy.

The aim of our study was to assess the incidence of pain flare and the effectiveness of stereotactic body radiotherapy (SBRT) in pain management of patients with bone oligometastases. We evaluated 48 patients accounting for 54 treatments. The Edmonton Classification System for Cancer Pain (ECS-CP) was applied to identify indicators of treatment-resistant pain, in patients with active pain (NRS≥2) at baseline. Statistical analysis was performed to identify predictors of pain flare and pain control. Pain flare occurred in 38% of treated patients (n=18/48): No correlation was found between pain flare and patient- or treatment-related variables. In the subset of patients with active pain at baseline (n=23), pain control was obtained in 62% of patients at 1year; median time to pain progression after SBRT was 29months (CI95% 6-52months). Presence of ≥2ECS-CP features was correlated with earlier pain progression (4 vs. 30months, p=0.012). Pain flare occurred in 38% of cases irrespectively of steroid premedication and dose regimen. In patient with baseline active pain, durable pain control was obtained. Presence of ≥2 complexity indicators at the ECS-CP assessment was correlated with impaired pain control and may deserve future investigation in prospective studies.

Prevalence and characteristics of breakthrough cancer pain in an outpatient clinic in a Catalan teaching hospital: incorporation of the Edmonton Classification System for Cancer pain into the diagnostic algorithm

BackgroundBreakthrough cancer pain (BTcP) is defined according to its principal characteristics: high intensity, short time interval between onset and peak intensity, short duration, potential recurrence over 24 h and non-responsiveness to standard analgesic regimes. The Edmonton Classification System for Cancer Pain (ECS-CP) is a classification tool that evaluates different dimensions of pain.The aim of this study was to measure prevalence and the main characteristics of BTcP in a sample of advanced cancer patients and to explore the complexity observed when ECS-CP is incorporated into BTcP diagnostics algorithm.MethodsDescriptive prevalence study (Retrospective chart review). Davies’ algorithm was used to identify BTcP and ECS-CP was used to recognize appropriate dimensions of pain. The study was conducted in a sample of advanced cancer patients attending hospital outpatient clinic in Lleida, Spain. 277 patients were included from 01/01/2014 to 31/12/2015. No direct contact was made with participants. The following information was extracted from the palliative care outpatient clinic database: age, gender, civil status, cognitive impairment status, functional performance status and variables related to tumour. Only BTcP cases were included.ResultsPrevalence of BTcP was 39.34% (63.9% men). Mean of age was 68.2 years. Main diagnosis was lung cancer (n = 154; 31.6%). Metastases were diagnosed in 83% of the sample. 138 patients (49.8%) were diagnosed with 1 type of BTcP and 139 (50.2%) were diagnosed with more than one type of BTcP. In total, 488 different types of BTcP were recorded (mean 1.75 ± 0, 9), 244 of these types (50%) presented a component of neuropathic pain. Addictive behaviour, measured through CAGE test, was present in 29.2% (N = 81) of the patients and psychological distress was present in 40.8% (n = 113).ConclusionsPrevalence of BTcP (39.34%) is similar to the one reflected in the existing literature. Study results indicate that the routine use of ECS-CP in a clinical setting allows us to detect more than one type of BTcP as well as additional complexity associated with pain (neuropathic, addictive behavior and psychological distress).

The Edmonton Classification System for Cancer Pain: a tool with potential for an evolving role in cancer pain assessment and management

Introduction: Undertreatment of cancer pain is associated with inadequate assessment and inconsistent or non-standardized classification, resulting in failure to both appreciate its multidimensional nature and appropriately target therapeutic interventions. This review examines the classification of cancer pain with a focus on the progressive development of the Edmonton Classification System for Cancer Pain (ECS-CP); the appropriateness of its constituent features, associated outcomes and its potential future development in cancer pain classification.Areas covered: A Medline search from 1989 to November 2017, using combined terms ‘cancer’ or ‘oncology’, ‘Edmonton’, ‘pain’ or ‘analgesia’, and ‘staging’ or ‘classification’, identified 280 records. A total of 20 studies with empirical data relating to validation studies of the ECS-CP or evaluation of either its constituent or proposed domains were selected for inclusion in the core review.Expert commentary: The ECS-CP is a tool in evolution and a valid template for further cancer pain classification development. The assessment of ECS-CP domains requires a standardized approach. The domain ratings can inform the therapeutic strategy, and are associated with pain management outcomes, particularly stable pain control. The ECS-CP enables standardized reporting, based on patients’ pain and related characteristics, and thus may improve the validity of comparisons across research study samples.

Assessing the prognostic features of a pain classification system in advanced cancer patients.

The Edmonton Classification System for Cancer Pain (ECS-CP) has been shown to predict pain management complexity based on five features: pain mechanism, incident pain, psychological distress, addictive behavior, and cognitive function. The main objective of our study was to explore the association between ECS-CP features and pain treatment outcomes among outpatients managed by a palliative care specialist-led interdisciplinary team. Initial and follow-up clinical information of 386 eligible supportive care outpatients were retrospectively reviewed and analyzed. Between the initial consultation and the first follow-up visit, the median ESAS pain intensity improved from 6 to 4.5 (p<0.0001) and the median total symptom distress score (0-100) improved from 38 to 31 (p<0.0001). At baseline, patients with neuropathic pain (p<0.001) and those with at least one ECS-CP feature (p=0.006) used a higher number of adjuvant medications. At follow-up, patients with neuropathic pain were less likely to achieve their personalized pain goal (PPG) (29 vs 72%, p=0.015). No statistically significant association was found between increasing sum of ECS-CP features and any of the pain treatment outcomes at follow-up. Neuropathy was found to be a poor prognostic feature in advanced cancer pain management. Increasing sum of ECS-CP features was not predictive of pain management complexity at the follow-up visit when pain was managed by a palliative medicine specialist. Further research is needed to further explore these observations.

Evaluating the prognostic effect of a pain classification system in patients with advanced cancer.

95 Background: The Edmonton Classification System for Cancer Pain (ECS-CP) has been shown to predict pain management complexity based on five features: pain mechanism, incident pain, psychological distress, addictive behavior, and cognitive function. The main objective of our study was to explore the association between increasing sum of negative ECS-CP features and achievement of good pain control at first follow up visit at an outpatient palliative care clinic. Methods: Initial and follow up clinical information of 409 eligible supportive care outpatients such as patient demographics, ECS–CP assessment, morphine equivalent daily dose (MEDD), opioid rotation, Edmonton Symptom Assessment Score (ESAS), and personalized pain goal (PPG) were retrospectively reviewed and analyzed. Results: Between the initial consultation and the first follow up visit, the median MEDD requirement increased from 30mg/day to 45mg/day (p &lt; 0.0001) and median pain intensity improved from 6 to 4 (p &lt; 0.0001). Increasing sum of negative ECS–CP features was associated with higher MEDD at consultation, with an increase from 30mg/day with no negative features to 40mg/day with ≥2 negative features (p = 0.046). There was no significant association between increasing sum of negative ECS-CP features and achievement of pain control at follow up visit (0.991, 95% CI: 0.747 – 1.304, p = 0.948). Conclusions: Increasing sum of negative ECS-CP features was associated with higher MEDD at referral but was not predictive of pain control at the follow up visit when pain was managed by a palliative medicine specialist. Further research is needed to further explore these observations.

The impact of a simplified documentation method for the Edmonton classification system for cancer pain (ECS-CP) on clinician utilization.

The use of standardized pain classification systems such as the ECS-CP can assist in the assessment and management of cancer pain. However, its completion has been limited due to its perceived complexity of decoding each feature. The objectives of this study were to determine the rate of clinician documentation and completion of the ECS-CP features after revision and simplification of the response for each feature. Electronic records of consecutive patient visits at the outpatient supportive care center seen by 12 palliative medicine specialists were collected at 6months before (pre-interventional period), 6 and 24months after (post-interventional period) the implementation of the simplified ECS-CP tool. Rate of ECS-CP documentation, completion, and analysis of patient and physician predictors were completed. One thousand and twelve patients' documentation was analyzed: 343 patients, before; 341 patients, 6months after, and 328 patients, 24months after the intervention. ≥2/5 items were completed before the intervention, 6months after the intervention and 24months after intervention in 0/343 (0%), 136/341 (40%), and 238/328 (73%), respectively (p<0.001). 5/5 items were completed before the intervention, 6months after the intervention and 24months after intervention in 0/343 (0%), 131/341 (38%), and 222/328 (68%), respectively, (p<0.001). There were no patient or physician predictors found significant for successful documentation of ECS-CP. Our findings suggest that significant simplification and intensive education is necessary for successful adoption of a scoring system. More research is needed in order to identify how to adopt tools for daily clinical practice in palliative care.

The impact of a simplified documentation method for the Edmonton Classification System for Cancer Pain (ECS-CP) on clinician utilization.

e21625Background: The use of standardized pain classification systems such as the ECS-CP can assist in the assessment and management of cancer pain. However, its completion has been limited due to ...

The routine use of the Edmonton classification system for cancer pain in an outpatient supportive care center.

180 Background: There is no standardized and universally accepted pain classification system for the assessment and management of cancer pain in both clinical practice and in research studies. The Edmonton Classification System for Cancer Pain (ECS-CP) is an assessment tool that has demonstrated value in assessing pain characteristics and response. The purpose of the study was to determine the relationship between the negative ECS-CP features and some pain related variables like pain intensity and opioid use. Also, we explored whether the number of negative ECS-CP features was associated with higher pain intensity. Methods: Electronic charts of 100 patients at the outpatient supportive care clinic in a comprehensive cancer center were reviewed for patient characteristics, initial ECS-CP assessment, the morphine equivalent daily dose (MEDD), opioid rotation, the Edmonton Symptom Assessment Score (ESAS), Memorial Delirium Assessment Scale (MDAS), performance status, and the use of adjuvant analgesics. Results: Ninety one out of the 100 charts were therefore eligible for analysis. The median age was 58.4 years. The most common primary cancer site was gastrointestinal cancer (22.1%). The median pain intensity was 6 and the median MEDD was 45mg. Incident pain was the most common ECS-CP feature (60%) and cognitive dysfunction was the least frequent feature (2%). Neuropathic pain was associated with higher median pain intensity (7 vs. 5, p=0.007) and median MEDD requirement (83 vs. 30, p=0.013). Psychological distress was associated with higher median pain intensity (7 vs. 5, p=0.042). Incident pain was also associated with a trend for higher pain intensity (6 vs 5, p= 0.06). A higher number of negative ECS-CP features was associated with higher pain intensity (p=0.01). Conclusions: The ECS-CP was successfully completed in the majority of patients, demonstrating its utility in routine clinical practice. Neuropathic pain and psychological distress were associated with higher pain intensity. Also, neuropathic pain was associated with higher MEDD. A higher sum of negative ECS-CP features was associated with higher pain intensity. Further studies will be needed to explore this observation.

(122) Neuropathic pain in a sample of nicotine addicted advanced cancer patients: practical outcomes using the DN4 tool

Pain is a frequent symptom detected among advanced cancer patients with an estimated prevalence of 70%. Cancer-related pain can either be nociceptive or neuropathic (can be presented at the same time!) and to establish its nature is key to provide effective pain relief. Neuropathic cancer pain is associated with greater requirements for pain medications than nociceptive pain. The Edmonton Classification System for Cancer pain (ECS-CP) was developed in order to help clinicians to classify cancer pain according to 5 items: Mechanism of pain (nociceptive vs neuropathic), incident pain, psychological distress, addictive behaviour and cognitive status.

Clinician's Commentary on Tatham et al.

Clinician's Commentary on Tatham et al.

The Edmonton Classification System for Cancer Pain: Comparison of Pain Classification Features and Pain Intensity Across Diverse Palliative Care Settings in Eight Countries

Standardized approaches for assessing and classifying cancer pain are required to improve treatment of patients with complex pain profiles. The Edmonton Classification System for Cancer Pain (ECS-CP) offers a starting point for the evolution of a standardized international classification system for cancer pain and was introduced into multisite research initiatives of the European Palliative Care Research Collaborative (EPCRC). The primary purpose of this study was to describe the prevalence of the five ECS-CP pain classification features: pain mechanism, incident pain, psychological distress, addictive behavior, and cognition--in a diverse international sample of patients with advanced cancer. A total of 1070 adult patients with advanced cancer were recruited from 17 sites in Norway, the United Kingdom, Austria, Germany, Switzerland, Italy, Canada, and Australia; 1051 of 1070 patients were evaluable. A clinician completed the ECS-CP for each enrolled patient. Additional information, including pain intensity, were also collected through patient self-reports, using touch-sensitive computers. Of 1051 evaluable patients, 670 (64%) were assessed by a clinician as having cancer pain: nociceptive pain (n=534; 79.7%); neuropathic pain (n=113; 16.9%); incident pain (n=408; 60.9%); psychological distress (n=212; 31.6%); addictive behavior (n=30; 4.5%); normal cognition (n=616; 91.9%). The prevalence of ECS-CP features and pain intensity scores (11-item scale; 0=none, 10=worst; rated as now) varied substantially across sites and locations of care. The ECS-CP is a clinically relevant systematic framework, which is able to detect differences in salient pain classification features across diverse settings and countries. Further validation studies need to be conducted in varied advanced cancer and palliative care settings to advance the development of the ECS-CP toward an internationally recognized pain classification system.

Characteristics of Cancer Pain in an Outpatient Palliative Care Center According To the ECS-CP (776)

1.Learn about the characteristics of cancer pain among advanced cancer patients seen at an outpatient palliative care center.2.Identify the features that are associated with higher pain intensity. The Edmonton Classification System for Cancer Pain (ECS-CP) has demonstrated value in predicting pain management complexity based on five features: pain mechanism, incident pain, psychological distress, addictive behavior, and cognitive function. There is however limited literature on ECS-CP use in the outpatient setting. We examined the characteristics of patients with cancer pain at our outpatient palliative care center using ECS-CP. Records of patients seen at our outpatient palliative care center were reviewed. Baseline characteristics, morphine equivalent daily dose (MEDD), opiate rotation, Edmonton Symptom Assessment System (ESAS), Memorial Delirium Assessment Scale (MDAS) and CAGE scores were obtained at the initial visit. 91 consecutive patients with advanced cancer were included. The median age was 58 years, 55% were female, and 70% were white. The most common pain type was nociceptive pain (68%). 62% had incidental pain, 52% had psychological distress, and 2/91 (<1%) had cognitive impairment. The median MEDD was 45 and the CAGE score was positive in 7.8% of patients. There were no associations between pain intensity and age, gender, race or cancer type. ECS-CP psychosocial distress (r = 0.18, P = 0.07), addictive behavior (r = 0.09, P = 0.28), and cognitive function (r = 0.02, P = 0.8) were also not associated with pain intensity. There was however significant association between pain intensity and ECS-CP pain type (r = 0.29, P = 0.005), incidental pain(r = 0.21, P = 0.04), MEDD(R = 0.23, P = 0.02), and opioid rotation(r = 0.32, P = 0.002). Patients with higher pain intensity are more likely to have nociceptive pain, incidental pain, higher MEDD scores and are likely to have opioid rotation. Further studies are needed to optimize the use of ECS-CP for better symptom control.

An international multicentre validation study of a pain classification system for cancer patients

PurposeThe study’s primary objective was to assess predictive validity of the Edmonton Classification System for Cancer Pain (ECS-CP) in a diverse international sample of advanced cancer patients. We hypothesised that patients with problematic pain syndromes would require more time to achieve stable pain control, more complicated analgesic regimens and higher opioid doses than patients with less complex pain syndromes. MethodsPatients with advanced cancer (n=1100) were recruited from 11 palliative care sites in Canada, USA, Ireland, Israel, Australia and New Zealand (100 per site). Palliative care specialists completed the ECS-CP for each patient. Daily patient pain ratings, number of breakthrough pain doses, types of pain adjuvants and opioid consumption were recorded until study end-point (i.e. stable pain control, discharge and death). ResultsA pain syndrome was present in 944/1100 (86%). In univariate analysis, younger age, neuropathic pain, incident pain, psychological distress, addictive behaviour and initial pain intensity were significantly associated with more days to achieve stable pain control. In multivariate analysis, younger age, neuropathic pain, incident pain, psychological distress and pain intensity were independently associated with days to achieve stable pain control. Patients with neuropathic pain, incident pain, psychological distress or higher pain intensity required more adjuvants and higher final opioid doses; those with addictive behaviour required only higher final opioid doses. Cognitive deficit was associated with fewer days to stable pain control, lower final opioid doses and fewer pain adjuvants. ConclusionThe replication of previous findings suggests that the ECS-CP can predict pain complexity in a range of practice settings and countries.

Is Pain Intensity a Predictor of the Complexity of Cancer Pain Management?

The lack of a standardized cancer pain (CP) classification system prompted the development of the Edmonton Classification System for Cancer Pain (ECS-CP). Its five features have demonstrated value in predicting pain management complexity. Pain intensity (PI) at initial assessment has been proposed as having additional predictive value. We hypothesized that patients with moderate to severe CP would take longer to achieve stable pain control, use higher opioid doses, and require more complicated analgesic regimens than would patients with mild CP at initial assessment. A secondary analysis of a multicenter ECS-CP validation study involving patients with advanced cancer was conducted (n = 591). Associations between PI and length of time to stable pain control (Cox regression), final opioid dose (Kruskal-Wallis one-way analysis of variance), and number of adjuvant modalities (chi(2)) were calculated. PI at initial assessment was defined using a numerical scale as mild (0 to 3), moderate (4 to 6), or severe (7 to 10). Patients with moderate and severe pain required a significantly longer time to achieve stable pain control (P < .0001). PI was a significant predictor of length of time to stable pain control in the univariate regression analysis. The four significant predictors in the multivariate model were moderate and severe PI (P < .0001), age (P = .001), and neuropathic pain (P = .002). Patients with moderate to severe pain required significantly higher final opioid doses (P < .0001) and more adjuvant modalities (P = .015). PI at initial assessment is a significant predictor of pain management complexity and length of time to stable pain control. Incorporation of this feature into the ECS-CP needs additional consideration.

Audit of Resource Utilization in a Regional Palliative Care Program Using the Edmonton Classification System for Cancer Pain (ECS-CP)

Audit of Resource Utilization in a Regional Palliative Care Program Using the Edmonton Classification System for Cancer Pain (ECS-CP)

A “TNM” classification system for cancer pain: The Edmonton Classification System for Cancer Pain (ECS-CP)

The purpose of this paper is to provide an overview of the development of a "TNM" cancer pain classification system for advanced cancer patients, the Edmonton Classification System for Cancer Pain (ECS-CP). Until we have a common international language to discuss cancer pain, understanding differences in clinical and research experience in opioid rotation and use remains problematic. The complexity of the cancer pain experience presents unique challenges for the classification of pain. To date, no universally accepted pain classification measure can accurately predict the complexity of pain management, particularly for patients with cancer pain that is difficult to treat. In response to this gap in clinical assessment, the Edmonton Staging System (ESS), a classification system for cancer pain, was developed. Difficulties in definitions and interpretation of some aspects of the ESS restricted acceptance and widespread use. Construct, inter-rater reliability, and predictive validity evidence have contributed to the development of the ECS-CP. The five features of the ECS-CP--Pain Mechanism, Incident Pain, Psychological Distress, Addictive Behavior and Cognitive Function--have demonstrated value in predicting pain management complexity. The development of a standardized classification system that is comprehensive, prognostic and simple to use could provide a common language for clinical management and research of cancer pain. An international study to assess the inter-rater reliability and predictive value of the ECS-CP is currently in progress.

Applying the Delphi process to palliative care tool development: lessons learned

The Delphi technique is an effective method for collecting and synthesizing informed opinions on a highly focused task, from a diverse group of experts who have specialized knowledge in an area of interest. This method has been successfully applied to palliative care research but not commonly to palliative care tool development. The Delphi technique has recently been employed in the development of two palliative pain assessment tools: the Edmonton Classification System for Cancer Pain (ECS-CP) and the Alberta Breakthrough Pain Assessment Tool for Research (ABPAT-R). The purpose of this paper is to: (a) report on our experience of using the Delphi technique for gathering validity evidence for the ECS-CP and ABPAT-R; (b) identify challenges in using this technique including sampling, study and survey design, consensus setting and response rates; and (c) suggest approaches that can add to its effectiveness in national and international collaborations in palliative care instrument development and research. Depending on the design, the Delphi technique can facilitate national or international cooperation both asynchronously (e.g., with mail-out or electronic surveys) and synchronously (e.g., with face-to-face meetings or videoconferencing). International input can assure palliative care tools are relevant in diverse clinical settings and practice cultures. The use of the Delphi technique in palliative care tool development may thereby facilitate international collaborations, rapid knowledge transfer, and effective uptake of novel tools across diverse palliative care settings.

A validation study of a pain classification system for advanced cancer patients using content experts: the Edmonton Classification System for Cancer Pain

The purpose of this study was to gather construct validity evidence for a pain classification system for advanced cancer patients using content experts. Two expert panels, representing regional (Panel A, n = 18) and national/international (Panel B, n = 52) palliative medicine and pain specialists, were purposefully selected to participate in a modified Delphi survey technique, to evaluate an existing pain classification system, the Revised Edmonton Staging System (rESS). Each panel participated in two survey rounds, with response rates of 67% (Panel A, Round 1), 39% (Panel A, Round 2), 56% (Panel B, Round 1) and 64% (Panel B, Round 2). The rESS consists of five features: mechanism of pain, incidental pain, psychological distress, addictive behavior and cognitive function. Most participants either agreed or strongly agreed with including the five existing rESS features in a pain classification system, ranging from 67% (Panel A, cognitive function) to 100% (Panel B, mechanism of pain). Most participants suggested keeping the current definitions for these features, with some revisions. Based on participant feedback, definitions for incidental pain, psychological distress, addictive behavior and cognitive function were revised, including the development of guidelines for use. To reflect its intended use as a classification system, the name of the instrument was changed to the Edmonton Classification System for Cancer Pain (ECS-CP).