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Worldwide, the prevalence of cancer is rising and so too is the number of patients who survive their cancer for many years thanks to the therapeutic successes of modern oncology. One of the most frequent and disabling symptoms of cancer is pain. In addition to the pain caused by the cancer, cancer treatment may also lead to chronic pain. Despite its importance, chronic cancer-related pain is not represented in the current International Classification of Diseases (ICD-10). This article describes the new classification of chronic cancer-related pain for ICD-11. Chronic cancer-related pain is defined as chronic pain caused by the primary cancer itself or metastases (chronic cancer pain) or its treatment (chronic postcancer treatment pain). It should be distinguished from pain caused by comorbid disease. Pain management regimens for terminally ill cancer patients have been elaborated by the World Health Organization and other international bodies. An important clinical challenge is the longer term pain management in cancer patients and cancer survivors, where chronic pain from cancer, its treatment, and unrelated causes may be concurrent. This article describes how a new classification of chronic cancer-related pain in ICD-11 is intended to help develop more individualized management plans for these patients and to stimulate research into these pain syndromes. [ABSTRACT FROM AUTHOR]

Purpose of review Gabapentinoids are frequently used in the management of cancer pain. In recent Cochrane systematic reviews, although there was an abundance of evidence relating to non-cancer pain, only a few studies related to cancer pain. This review summarizes recent randomised controlled trials (RCTs) evaluating the use of gabapentinoids for tumour-related (as monotherapy or part of combination therapy) and treatmentrelated pain. Recent findings For tumour-related pain, ten out of thirteen studies showed statistically significant benefits in favour of gabapentinoids. When used, as part of monotherapy or combination therapy, benefits were observed in five out of six studies evaluating gabapentin, and in six out of eight studies evaluating pregabalin. For treatment-related pain, none of the four studies (two gabapentin, two pregabalin) showed statistically significant benefits in favour of gabapentinoids. Unfortunately, many of the studies included were limited by small sample size, lack of blinding, and inadequate follow-up. Summary More and better quality studies are required, although it may be challenging to accomplish in this patient population. Gabapentinoids may offer benefits to cancer patients with pain, but careful titration and monitoring of adverse effects is necessary. [ABSTRACT FROM AUTHOR]

Neuropathic pain (NP) in cancer patients lacks standards for diagnosis. This study is aimed at reaching consensus on the application of the International Association for the Study of Pain (IASP) special interest group for neuropathic pain (NeuPSIG) criteria to the diagnosis of NP in cancer patients and on the relevance of patient-reported outcome (PRO) descriptors for the screening of NP in this population. An international group of 42 experts was invited to participate in a consensus process through a modified 2-round Internet-based Delphi survey. Relevant topics investigated were: peculiarities of NP in patients with cancer, IASP NeuPSIG diagnostic criteria adaptation and assessment, and standardized PRO assessment for NP screening. Median consensus scores (MED) and interquartile ranges (IQR) were calculated to measure expert consensus after both rounds. Twenty-nine experts answered, and good agreement was found on the statement “the pathophysiology of NP due to cancer can be different from non-cancer NP” (MED = 9, IQR = 2). Satisfactory consensus was reached for the first 3 NeuPSIG criteria (pain distribution, history, and sensory findings; MEDs ⩾ 8, IQRs ⩽ 3), but not for the fourth one (diagnostic test/imaging; MED = 6, IQR = 3). Agreement was also reached on clinical examination by soft brush or pin stimulation (MEDs ⩾ 7 and IQRs ⩽ 3) and on the use of PRO descriptors for NP screening (MED = 8, IQR = 3). Based on the study results, a clinical algorithm for NP diagnostic criteria in cancer patients with pain was proposed. Clinical research on PRO in the screening phase and on the application of the algorithm will be needed to examine their effectiveness in classifying NP in cancer patients. [ABSTRACT FROM AUTHOR]

Abstract: Pain in cancer patients remains common and is often associated with insufficient prescribing of targeted analgesia. An explanation for undertreatment could be the failure to identify neuropathic pain mechanisms, which require additional prescribing strategies. We wanted to identify the prevalence of neuropathic mechanisms in patients with cancer pain to highlight the need for detailed assessment and to support the development of an international classification system for cancer pain. We searched for studies that included adult and teenage patients (age above 12years), with active cancer and who reported pain, and in which a clinical assessment of their pain had been made. We found 22 eligible studies that reported on 13,683 patients. Clinical assessment methods varied, and only 14 studies reported confirmatory testing for either sensory abnormality or diagnostic lesion to corroborate a diagnosis of neuropathic pain. We calculated that the prevalence of patients with neuropathic pain (95% confidence interval) varied from a conservative estimate of 19% (9.4% to 28.4%) to a liberal estimate of 39.1% (28.9% to 49.5%) when patients with mixed pain were included. The prevalence of pain with a neuropathic mechanism (95% confidence interval) ranged from a conservative estimate of 18.7% (15.3% to 22.1%) to a liberal estimate of 21.4% (15.2% to 27.6%) of all recorded cancer pains. The proportion of pain caused by cancer treatment was higher in neuropathic pain compared with all types of cancer pain. A standardised approach or taxonomy used for assessing neuropathic pain in patients with cancer is needed to improve treatment outcomes. [Copyright &y& Elsevier]

Abstract: The benefits of transcutaneous electrical nerve stimulation (TENS) for pain relief have not been reliably established, as most systematic reviews find poor methodological quality in many studies. The paradox within the evidence base for TENS is that despite identified sources of bias that may lead to an overestimation of treatment effects, no benefits for TENS can be clearly demonstrated. Conventional assessments of quality assume a single direction of bias, and little work has been undertaken examining other directions of bias. Our hypothesis was that low fidelity in studies (bias leading to an underestimation of treatment effects) may account for inconclusive findings. We included 38 studies from 3 recently published Cochrane systematic reviews that examined TENS for acute, chronic, and cancer pain. We extracted data relating to treatment allocation, application of TENS and to the assessment of outcomes. We quantified these data and judged this against standardised assessment criteria using a “traffic light” approach based on the number of studies reaching the standard. We identified significant sources of potential bias in both directions in relation to study design and implementation fidelity that have not been quantified previously. Suboptimal dosing of TENS and inappropriate outcome assessment were particularly prevalent weaknesses indicating low fidelity. We propose criteria for judging directions of bias in future studies of TENS that may be adapted to assess other trials in which implementation fidelity is important, such as other nonpharmacological interventions for pain. Poor implementation fidelity was identified as a significant source of bias in systematic reviews of TENS studies and might explain lack of consistent treatment effects of TENS in pain. Here, criteria for assessing methodology are proposed for use in designing future clinical trials of TENS. [Copyright &y& Elsevier]

The article discusses a study which aimed to describe the current position of educational interventions in cancer pain management. Findings showed that barriers to good cancer pain control center on the lack of knowledge or poor attitudes towards pain and opioid analgesia. It concluded that educational interventions should be part of routine clinical practice alongside optimal oncological and analgesic management.

Abstract: This review aimed to quantify the benefit of patient-based educational interventions in the management of cancer pain. We undertook a systematic review and meta-analysis of experimentally randomised and non-randomised controlled clinical trials identified from six databases from inception to November 2007.Two reviewers independently selected trials comparing intervention (formal instruction on cancer pain and analgesia on an individual basis using any medium) to usual care or other control in adults with cancer pain. Methodological quality was assessed, and data extraction undertaken by one reviewer with a second reviewer checking for accuracy. We used random effects model to combine the effect estimates from studies. Main outcome measures were effects on knowledge and attitudes towards cancer pain and analgesia, and pain intensity. Twenty-one trials (19 randomised) totalling 3501 patients met inclusion criteria, and 15 were included in the meta-analysis. Compared to usual care or control, educational interventions improved knowledge and attitudes by half a point on 0–5 rating scale (weighted mean difference 0.52, 95% confidence interval 0.04–1.0), reduced average pain intensity by over one point on 0–10 rating scale (WMD −1.1, −1.8 to −0.41) and reduced worst pain intensity by just under one point (WMD −0.78, −1.21 to −0.35). We found equivocal evidence for the effect of education on self-efficacy, but no significant benefit on medication adherence or on reducing interference with daily activities. Patient-based educational interventions can result in modest but significant benefits in the management of cancer pain, and are probably underused alongside more traditional analgesic approaches. [Copyright &y& Elsevier]

Abstract: Chronic pain is generally regarded as being divided into two mutually exclusive pain mechanisms: nociceptive and neuropathic. Recently, this dichotomous approach has been questioned and a model of chronic pain being ‘more or less neuropathic’ has been suggested. To test whether such a spectrum exists, we examined responses by patients with chronic pain to validated neuropathic pain assessment tools and compared these with ratings of certainty about the neuropathic origin of pain by their specialist pain physicians. We examined 200 patients (100 each with nociceptive and neuropathic pain) and administered the self-complete Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS score) and the Neuropathic Pain Scale (NPS). Clinicians were asked to rate their certainty of the presence of neuropathic pain mechanisms on a 100mm visual analogue scale (VAS) (0=‘not at all neuropathic in origin’ to 100=‘completely neuropathic in origin’). The whole sample was divided into tertiles based on ascending ratings of diagnostic certainty by clinicians using the VAS and labelled ‘unlikely’, ‘possible’ and ‘definite’ neuropathic pain. There were significant differences in median S-LANSS and NPS composite scores between all tertile groups. There were also significant differences between many S-LANSS and NPS item scores between groups. We have shown that higher scores on both the S-LANSS and the NPS are indicative of greater clinician certainty of neuropathic pain mechanisms being present. These data support the theoretical construct that pain can be more or less neuropathic and that pain of predominantly neuropathic origin may be a useful clinical concept. [Copyright &y& Elsevier]

Introduction: Strong nonpainful transcutaneous electrical nerve stimulation (TENS) is prerequisite to a successful analgesic outcome although the ease with which this sensation is achieved is likely to depend on the magnitude of current amplitude (mA) between sensory detection threshold (SDT) and pain threshold, that is, the current window., Objectives: To measure the current window and participant's perception of the comfort of the TENS sensation at different body sites., Methods: A repeated measure cross-over study was conducted using 30 healthy adult volunteers. Current amplitudes (mA) of TENS [2 pulses per second (pps); 30 pps; 80 pps] at SDT, pain threshold, and strong nonpainful intensities were measured at the tibia (bone), knee joint (connective tissue), lower back [paraspinal (skeletal) muscle], volar surface of forearm (nerve) and waist (fat). The amplitude to achieve a strong nonpainful intensity was represented as a percentage of the current window. Data were analyzed using repeated measures analysis of variance., Results: Effects were detected for body site and frequency for SDT (P<0.001, P=0.018, respectively), current window (P<0.001, P<0.001, respectively), and strong nonpainful TENS as a percentage of the current window (P=0.002, P<0.001, respectively). The current window was larger for the knee joint compared with tibia (difference [95% confidence interval]=12.76 mA [4.25, 21.28]; P=0.001) and forearm (10.33 mA [2.62, 18.40]; P=0.006), and for the lower back compared with tibia (12.10 mA [1.65, 22.52]; P=0.015) and forearm (9.65 mA [1.06, 18.24]; P=0.019). The current window was larger for 2 pps compared with 30 pps (P<0.001) and 80 pps (P<0.001). Participants rated strong nonpainful TENS as most comfortable at the lower back (P<0.001) and least comfortable at the tibia and forearm (P<0.001)., Conclusions: TENS is most comfortable and easiest to titrate to a strong nonpainful intensity when applied over areas of muscle and soft tissue.

Objectives: To assess the health and quality of life associated with chronic pain of predominantly neuropathic origin (POPNO) on health and daily activity in the general population., Methods: The Self-complete Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) questionnaire, recently validated for identifying pain of predominantly neuropathic origin, was sent to 6000 adults identified from general practices in the United Kingdom, along with chronic pain identification and severity questions, the Brief Pain Inventory (BPI), the Neuropathic Pain Scale, and the SF-36 general health questionnaire., Results: With a corrected response rate of 52%, 3 groups of respondents were identified: those without chronic pain ("No Chronic Pain" group, n=1537); those with chronic pain who were S-LANSS positive indicating the presence of POPNO ("Chronic POPNO" group, n =241); and those with chronic pain who were S-LANSS negative ["Chronic Pain (non-POPNO)" group, n=1179]. The chronic POPNO group reported higher pain severity and had significantly poorer scores for all interference items of the BPI than those with chronic pain (non-POPNO). Mean scores from the Neuropathic Pain Scale were also significantly higher for the Chronic POPNO group. There were significant differences between the groups in all domains of the SF-36, with the Chronic POPNO group reporting the worst health. After adjusting for pain severity, age, and sex, the chronic POPNO group was still found to have poorer scores than the other Chronic Pain (non-POPNO) group in all domains of the SF-36 and all interference items in the BPI, indicating poorer health and greater disability., Discussion: This study confirms the importance of identifying neuropathic pain in the community, and the need for multidimensional management strategies that address all aspects of health.