***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Aims and Background Amitriptyline is the most common analgesic adjuvant used in cancer patients with neuropathic pain , even though no specific studies have demonstrated a benefit . A r and omized placebo-controlled , double-blind crossover study was design ed to evidence the effects of amitriptyline in patients with neuropathic cancer pain . Methods Sixteen advanced cancer patients with neuropathic pain on systemic morphine therapy , no longer receiving oncologic treatment , presenting moderate pain ( about 4 or more , but less than 7 , on a numerical scale of 0 - 10 ) in the last week , and given a stable morphine dose in the last 2 days were admitted to the study . During the first week of study , patients were administered 25 mg of amitriptyline or equivalent drops of placebo at night for 3 days and 50 mg for the following 4 days . Doses for patients aged more than 65 years were 15 mg ( first 3 days ) and 30 mg ( 3 days after ) . After a week , a crossover took place for the second week , with the other treatment at an inverse sequence . Opioid consumption , pain intensity , symptoms and adverse effects , mood , sleep , patient 's preference , quality of life before starting the study , the first week after and the second week after were recorded . Results No significant benefits in analgesia were found in the global pain intensity of the previous week of treatment , the least pain intensity or the pain evaluated just after a week of treatment , at the moment of the visit , when amitriptyline was compared with placebo . A significant difference was evidence d for the worst pain ( P < 0.035 ) . No differences in opioid doses during the period of study were found . Drowsiness , confusion and dry mouth were significantly more intense with amitriptyline than with placebo ( P < 0.036 , 0.003 , and 0.034 , respectively ) . There were no substantial differences between the two treatments in Spitzer 's quality of life score and for each item . No differences in patients ' preference for the two treatment periods were found . The analgesic effects of amitriptyline were slight and associated with adverse effects . Conclusions In light of the results obtained in the study , the extensive use of the drug for cancer pain should be question ed Neuropathic cancer pain represents a major challenge . Treatment often requires adjuvant analgesics , including gabapentin , to complement the effects of opioids . This study aim ed to compare the effectiveness and safety of gabapentin combined with an opioid versus opioid monotherapy for the management of neuropathic cancer pain . Seventy-five cancer patients who were receiving opioid therapy and reported sufficient pain relief of nociceptive , but not neuropathic , pain were enrolled . Sixty-three patients completed the study . Patients were r and omized to one of the following treatment protocol s : 1 ) gabapentin adjuvant to ongoing opioid treatment titrated according to pain response while opioid dose was kept constant ( group GO ) , and 2 ) continuation of opioid monotherapy according to the World Health Organization treatment ladder approach ( group OO ) . Changes in pain intensity , allodynia , and analgesic drug consumption were evaluated at Day 4 and Day 13 . Side effects were also recorded . Both treatments result ed in a significant reduction of pain intensity at Day 4 and Day 13 compared to baseline . However , mean pain intensity for burning and shooting pain was significantly higher in the OO group compared to the GO group at both the fourth ( P=0.0001 ) and 13th ( P=0.0001 ) days of the study . An earlier significant decrease ( at Day 4 , P=0.002 ) was observed for allodynia in the GO group compared to the OO group . The rate of side effects in the GO group was significantly lower than that in the OO group ( P=0.015 ) . These data suggest that gabapentin added to an opioid provides better relief of neuropathic pain in cancer patients than opioid monotherapy ; this combination of gabapentin and an opioid may represent a potential first-line regimen for the management of pain in these patients 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 The efficacy of phenytoin ( PHT ) , buprenorphine ( Bu ) , and Bu+PHT for the relief of  cancer pain of various etiologies was evaluated in a r and omized , double-blind study of 3 groups , each comprised of 25 patients . Treatment duration was 1 month . PHT ( 100 mg by mouth twice daily ) provided greater than 50 % pain relief to 18 patients ( 72 % ) and greater than 75 % relief to 4 ( 16 % ) . Bu ( 0.2 mg sublingually twice daily ) gave 21 patients ( 84 % ) greater than 50 % relief and 15 patients ( 60 % ) greater than 75 % relief . Of the Bu-treated patients , 8 had major side effects , while none of the PHT-treated patients experienced significant untoward reactions .  Combined therapy ( PHT , 50 mg PO+Bu 0.1 mg SL twice daily ) provided greater than 50 % pain relief to 22 patients ( 88 % ) and greater than 75 % to 18 ( 72 % ) ; only 3 patients experienced a significant side effect . This study suggests that phenytoin has mild-to-moderate pain-relieving properties of its own and can significantly enhance buprenorphine analgesia . By permitting a lower opioid dose , it may reduce the occurrence of opioid-related side effects .  PHT 's lack of serious side effects , as well as its documented anxiolytic and antidepressant actions , may add to its comparative usefulness . Further clinical trials of PHT as a coanalgesic and /or adjuvant agent in cancer pain are warranted 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 Gabapentin was administered as an " add on " therapy to 22 patients with neuropathic cancer pain only partially responsive to opioid therapy .  Global pain , burning pain , shooting pain episodes , and allodynia were assessed separately . Gabapentin was given for at least a week and efficacy was assessed after 7 to 14 days of therapy . Global pain score decreased from a mean ( + /- SD ) of 6.4 ( + /- 1.5 ) to 3.2 ( + /- 1.3 ) ( 95 % confidence interval of the baseline minus final score differences [ 95 % CI ] = 1.0 - 2.4 ) . Burning pain intensity decreased from a mean ( + /- SD ) of 5.1 ( + /- 3.6 ) to 2.0 ( + /- 2.3 ) ( 95 % CI = 1.5 - 3.8 ) , and episodes of shooting pain decreased in frequency from 7.2 ( + /- 3.7 ) to 2.2 ( + /- 2.2 ) daily episodes ( 95 % CI = 1.8 - 4.3 ) . Allodynia was found in 9 patients and disappeared in 7 during gabapentin administration . Twenty patients judged the new drug efficacious in relieving their symptoms . The potential role of gabapentin as an adjuvant to opioid analgesia in cancer pain is discussed BACKGROUND Gabapentin has been evaluated in the treatment of nonmalignant neuropathic pain , however , there is little direct evidence evaluating its efficacy in cancer-related neuropathic pain . OBJECTIVE 
    Output:
    
Included studies suggested that adjuvants improve pain control within 4–8 days when added to opioids for cancer pain ; the strongest evidence supports gabapentin .
However , a reduction in pain intensity of greater than 1 point on a 0–10 numerical rating scale is unlikely , but an increase in adverse events is likely .
For all adjuvants , the effect size was much less than that seen in patients with non-cancer neuropathic pain .