***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: The optimal assessment of cancer pain includes a detailed description of pain characteristics and classification by both syndrome and likely mechanisms . In the clinical setting , the interpretation of this information is aided by knowledge of the available clinical experiences on these aspects of the pain . Unfortunately , existing data are limited . There have been few large surveys of cancer pain characteristics and syndromes , and comparative data from patients in different parts of the world are entirely lacking . To better define the characteristics of cancer pain syndromes the Task Force on Cancer Pain of the International Association for the Study of Pain ( IASP ) conducted a prospect i ve , cross-sectional , international , multicenter survey of pain specialists and their patients . From a total of 100 clinicians who described themselves as cancer pain practitioners in the IASP membership directory , 51 agreed to participate in the survey and a total of 58 provided data . These clinicians resided in 24 countries and evaluated a total of 1095 patients with severe cancer pain mostly requiring opioid medication  , using a combination of patient-rated and observer-rated measures . The patient-rated scales comprised a  pain intensity measure  chosen from the brief pain inventory . The observer-rated information included demographic and tumor-related data , and responses on checklists of pain syndromes and pathophysiologies . Patients were heterogeneous in terms of demographics and tumor-related information . More than 76 % had a Kamofsky performance status score < or = 70 . Almost one-quarter of the patients experienced two or more pains . A large majority of the patients ( 92.5 % ) had one or more pains caused directly by the cancer ; 20.8 % of patients had one or more pains caused by cancer therapies . The average ( SD ) duration of pain was 5.9 ( 10.5 ) months . Approximately two-thirds of patients ( 66.7 % ) reported that the worst pain intensity during the day prior to the survey was > or = 7 on a 10-point numeric scale . The factors that were univariately associated with higher pain intensity included the presence of breakthrough pain , somatic pain or neuropathic pain , age younger than 60 years , and lower performance status score . A multivariate model suggested that the presence of breakthrough pain , somatic pain , and lower performance status were the most important predictors of intense pain . Pains that were inferred by the treating clinician to be nociceptive and due to somatic injury occurred in 71.6 % of the patients . Pains labeled nociceptive visceral were noted in 34.7 % and pains inferred to have neuropathic mechanisms occurred in 39.7 % . In a broad classification , the major pain syndromes comprised bone or joint lesions ( 41.7 % of patients ) , visceral lesions ( 28.1 % ) , soft tissue infiltration ( 28.3 % ) , and peripheral nerve injuries ( 27.8 % ) . Twenty-two types of pain syndromes were most prevalent . Large differences in the diagnosis of breakthrough pain by clinicians of different countries suggest that this phenomenon is either defined or recognized differently across countries . These data confirm , in segment of the cancer population experiencing severe pain , in different parts of the world , that cancer pain characteristics , syndromes and pathophysiologies are very heterogeneous . Predictors of worsening pain can be identified . The data provide a useful context for the interpretation of pain-related information acquired in both clinical and research setting s. They suggest the need for future studies and the potential usefulness of a written checklist for cancer pain syndromes and pathophysiologies Head and neck cancers are relatively uncommon malignancies and the characteristics of pain and functional impairments in survivors are not well studied . To characterize the incidence , location , severity , types and causes of pain ; associated functional impairments , and pain management methods , the medical charts of 40 consecutive out patients with biopsy-proven head and neck cancers were review ed . Pain was severe in 52 % ( N = 21 ) , and was located near sites of tumor origin . Pain was caused by tumor recurrence in 35 % ( N = 14 ) , treatment sequelae in 30 % ( N = 12 ) , multiple etiologies in 25 % ( N = 10 ) , and unrelated causes in 10 % ( N = 4 ) . Pains were mixed nociceptive and neuropathic pain in 37.5 % ( N = 15 ) , nociceptive pain in 32.5 % ( N = 13 ) , myofascial in 13.0 % ( N = 6 ) , neuropathic in 7.5 % ( N = 3 ) ; and other mixed types in 7.5 % ( N = 3 ) . Despite the high prevalence of dysphagia ( 82 % ) , 60 % used orally administered opioid-nonopioid analgesics .  Physical disfigurement ( 87.5 % ; N = 35 ) , dysphagia ( 62.5 % , N = 25 ) , and jaw dysfunction ( 40.0 % ; N = 16 ) were the most frequent physical impairments . Multiple regression analysis showed that the presence of skull base or m and ibular bone involvement had significant influence on the severity of pain ( P = 0.03 , adjusted R2 0.25 ) We conclude that pain in head and neck cancer can be chronic , severe , and persistent despite completion of oncologic treatment BACKGROUND The European Pain in Cancer survey sought to increase underst and ing of cancer-related pain and treatment across Europe . PATIENTS AND METHODS Patients with all stages of cancer participated in a two-phase telephone survey conducted in 11 European countries and Israel in 2006 - 2007 . The survey screened for patients experiencing pain at least weekly , then r and omly selected adult patients with pain of at least moderate intensity occurring several times per week for the last month completed a detailed attitudinal question naire . RESULTS Of 5084 adult patients contacted , 56 % suffered moderate-to-severe pain at least monthly . Of 573 patients r and omly selected for the second survey phase , 77 % were receiving prescription-only analgesics  , with 41 % taking  strong opioids either alone or with other drugs for cancer-related pain . Of those prescribed analgesics , 63 % experienced breakthrough pain . In all , 69 % reported pain-related difficulties with everyday activities ; however , 50 % believed that their quality of life was not considered a priority in their overall care by their health care professional . CONCLUSIONS Across Europe and Israel , treatment of cancer pain is suboptimal . Pain and pain relief should be considered integral to the diagnosis and treatment of cancer ; management guidelines should be revised to improve pain control in patients with cancer Neuropathic pain syndromes are one of the major problems of cancer pain treatment . The present study surveys 593 cancer patients treated by a pain service following the WHO guidelines for relief of cancer pain . Of these , 380 presented with nociceptive , 32 with neuropathic and 181 with mixed ( nociceptive and neuropathic ) pain . In patients with nociceptive , mixed and neuropathic pain , the average duration of evaluated pain treatment was 51 , 53 and 38 days , respectively . Non-opioid or opioid analgesics were given to 99 % , 96 % and 79 % , antidepressants to 8 % , 25 % and 19 % , anticonvulsants to 2 % , 22 % and 38 % and corticosteroids to 26 % , 35 % and 22 % of patients , respectively . Systemic analgesia was supported by palliative antineoplastic treatment ( 48 % , 56 % and 38 % of patients ) , nerve blocks ( 3 % , 6 % and 6 % ) , psychotherapy ( 3 % , 7 % and 3 % ) , physiotherapy ( 6 % , 12 % and 13 % ) and transcutaneous electric nerve stimulation ( 1 % , 6 % and 6 % ) . Analgesic treatment result ed in a significant pain relief in all groups of patients , as the mean pain intensity ( NRS ) decreased from 66 ( nociceptive ) , 65 ( mixed ) and 70 ( neuropathic ) on admission to 26 , 30 and 28 after 3 days and 18 , 17 and 21 at the end of survey . The total outcome of pain treatment was not predicted by the design ation to nociceptive , mixed or neuropathic pain . In conclusion , neuropathic cancer pain is not intractable and can be relieved in the majority of patients by treatment following the WHO guidelines Sixty consecutive lung cancer patients referred to a palliative care service  were followed until death to obtain specific information about the prevalence , characteristics and localization of pain . To determine the course of treatment , an  Opioid Escalation Index and Effective Analgesic Score  were calculated . The prevalence of pain was almost 90 % . Chest and lumbar pain were the most common sites with a clear correlation between site and metastases for the chest . Somatic incident pain did not achieve good pain relief while patients with neuropathic pain did not show any particular disadvantage compared to those exhibiting somatic or visceral pain . Mean Opioid Escalation Index and percentage of pain control observed in lung cancer patients were similar to those recorded in the general cancer population The Leeds Assessment of Neuropathic Symptoms and Signs Scale ( LANSS ) is a simple bedside test in two parts-a patient-completed question naire and a brief clinical assessment . Its diagnostic capabilities have never been tested in patients with cancer pain . To determine these we conducted a prospect i ve study in out patients with head and neck cancer . All patients with pain completed the LANSS  and underwent a medical assessment with a palliative care physician , whose findings were then review ed by a pain specialist blinded to the LANSS scores . We assessed acceptability and underst and ing of the LANSS by patients and calculated the sensitivity and specificity of total LANSS scores and subscores derived from the patient-completed section . Of 130 patients approached , 125 took part . 25 ( 20 % ) of these had cancer related pain , mean score on an 11 point numerical rating scale 6.3 ( median 6.0 , range 3 - 10 ) . Average age was 60 years ( median 60 , range 27 - 84 ) ; 56 % were male .  LANSS completion time was about five minutes , and the procedure was acceptable to all patients . The pain specialist diagnosed neuropathic pain in 14/25 patients , in 13 of whom the neuropathic pain was part of a mixed pain picture . The LANSS correctly identified 11 of these cases ( sensitivity 79 % ; specificity 100 % ) . The patient-completed section alone had a sensitivity of 86 % and a specificity of 91 % . The LANSS is a simple and suitable screening test for neuropathic pain in patients with head and neck cancer related pain , although some modifications might improve it & NA ; Although pain assessment is a vital preliminary step towards the satisfactory control of cancer pain , data on the prevalence of different pain syndromes are rare . In a prospect i ve study of 2266 cancer patients , we assessed localisations , aetiologies and pathophysiological mechanisms of the pain syndromes . Thirty percent of the patients presented with 1 , 39 % with 2 and 31 % with 3 or more distinct pain syndromes . The majority of patients had pain caused by cancer ( 85 % ) or antineoplastic treatment ( 17 % ) ; 9 % had pain related to cancer disease and 9 % due to aetiologies unrelated to cancer . Pain could be classified as originating from nociceptors in bone ( 35 % ) , soft tissue ( 45 % ) or visceral structures ( 33 % ) or otherwise as of as neuropathic origin ( 34 % ) . In most patients , pain syndromes were located in the lower back ( 36 % ) , abdominal region ( 27 % ) , thoracic region ( 23 % ) , lower limbs ( 21 % ) , head ( 17 % ) and pelvic region ( 15 % ) . The main pain syndrome was also coded according to the IASP Classification of Chronic Pain . Regions and systems affected by the main pain syndrome showed large variation depending on the site of cancer origin , whereas temporal characteristics , intensity and aetiology were not markedly influenced by the cancer site . The variety of pain syndromes evaluated in our patients confirms the importance of comprehensive pain assessment prior to treatment Predictive validity of each word from the McGill Pain Question naire ( MPQ ) has not been investigated in relation to pain etiology . The purpose of this study was to explore differences in the words used to describe nociceptive and neuropathic pain . Patients with lung cancer ( N = 123 ) selected words from the 78 MPQ pain quality descriptors  and indicated the corresponding pain site for each word . Using only the MPQ pain location , and the cancer and treatment data abstract ed from medical records , each pain site was classified as nociceptive or neuropathic ( etiology ) . Pain etiology and quality descriptors were tested for proportional differences with sensitivity , specificity , and predictive value calculated for statistically significant descriptors . Of the 457 pain sites , 343 were classified as nociceptive ( 75 % ) , 114 as neuropathic ( 25 % ) . Lacerating , stinging , heavy , and suffocating were selected for a significantly larger proportion of nociceptive sites whereas throbbing , aching , numb , tender , punishing , pulling , tugging , pricking , penetrating , punishing , miserable , and nagging were selected for a larger proportion of neuropathic sites . Ten words correctly predicted 78 % of the sites with 81 % sensitivity to nociceptive pain and 59 % sensitivity to neuropathic pain . Interestingly , several pain quality descriptors ( burning , shooting , flashing , tingling , itching , and cold ) previously associated with ne 
    Output:
    
The proportion of pain caused by cancer treatment was higher in neuropathic pain compared with all types of cancer pain .