Neuropathic Cancer Pain Research Articles

Phase III, international, multicentre, double-blind, dose increment, parallel-arm, randomised controlled trial of duloxetine versus pregabalin for opioid-unresponsive neuropathic cancer pain: a JORTC-PAL16 trial protocol

IntroductionManagement of neuropathic cancer pain (NCP) refractory to regular opioids remains an important challenge. The efficacy of pregabalin for NCP except chemotherapy-induced peripheral neuropathy (CIPN) has already been confirmed in...

Применение прегабалина для лечения периферической и центральной нейропатической боли у взрослых (научный обзор)

Предпосылки. Прегабалин является габапентиноидом нового поколения с улучшенными фармакологическими свойствами. Нейропатическая боль — актуальная проблема современной медицины, в отдельных случаях трудно поддающаяся лечению. В связи с этим цель настоящего обзора сводится к оценке эффективности прегабалина при лечении периферической и центральной нейропатической боли в клинических исследованиях высокого уровня. Материалы и методы. В настоящий обзор были включены рандомизированные контролируемые исследования (РКИ) с двойным слепым дизайном и их метаанализы. Результаты. В выполненных исследованиях была подтверждена обезболивающая активность прегабалина у пациентов с нейропатической болью: при болевой диабетической нейропатии (9 РКИ), постгерпетической невралгии (4 РКИ), центральной нейропатической боли вследствие повреждения спинного мозга (3 РКИ), посттравматической периферической нейропатической боли, включая хроническую послеоперационную боль (2 РКИ), нейропатической боли при раке (2 РКИ). Требует дальнейшего уточнения эффективность препарата при центральной нейропатической боли вследствие повреждения головного мозга и хронической боли в нижней части спины (в обоих случаях по 2 РКИ с результатами «есть эффект/нет эффекта»). Дополнительно у пациентов с нейропатической болью прегабалин уменьшал нарушение сна, улучшал общее состояние и качество жизни. Кроме того, уменьшалась выраженность аллодинии при постгерпетической невралгии, тревоги при центральной нейропатической боли, снижалась потребность в морфине при нейропатической боли вследствие рака и выраженность обусловленных им запоров, усиливались эффекты нестероидных противовоспалительных средств при хронической боли в нижней части спины. Эффективность прегабалина у пожилых пациентов была сравнима с таковой у более молодых пациентов. Прегабалин назначают в дозе 75 мг/день в 1 прием или в дозе 150 мг/день в 2 приема. Затем дозу постепенно увеличивают до 300–600 мг/день таким образом, чтобы соотношение эффективность/безопасность было оптимальным. Обезболивающий эффект начинает появляться в первую неделю терапии, в зависимости от выбранного дозового режима и тяжести патологии. Побочные эффекты при лечении прегабалином носят легкий и умеренный характер, часто самостоятельно исчезают по ходу лечения. Наиболее частыми побочными эффектами были головокружение (прегабалин — 26,3 %, плацебо — 9 %), сонливость (16,8 и 7 % соответственно) и периферические отеки (8,9 и 0,4 % соответственно). Несмотря на то что частота побочных эффектов для прегабалина превышала таковую для плацебо и в ряде случаев приводила к прекращению приема препарата, авторы исследований сообщают о хорошей переносимости прегабалина. Выводы. Результаты исследований высокого уровня подтверждают эффективность прегабалина в лечении пациентов с периферической и центральной нейропатической болью. Для препарата была характерна хорошая переносимость.

Dezocine as a potent analgesic: overview of its pharmacological characterization.

Dezocine, a synthetic opioid, introduced in 1970s as an analgesic, was redeveloped for relieving moderate to severe pain by Yangtze River Pharmaceutical Group in China in 2009. To date, dezocine occupies 45% of China's opioid analgesic market. Along with dezocine being a dominated painkiller, a certain amount of research was conducted to elucidate dezocine's action. In this review we summarize the current knowledge on the receptor, preclinical and clinical pharmacology of dezocine. Briefly, preclinical data show that dezocine is effective under varying pain conditions, particularly chronic neuropathic pain and cancer pain, through activation of opioid receptors, and inhibition of norepinephrine reuptake. Clinical data establish the effectiveness of dezocine either as a primary analgesic for postoperative pain management or a supplement for balanced analgesia. The receptor profile of dezocine is different from known pure μ agonists, and allows it to be used in combination with other opioids for additivity in efficacy or lower incidence of adverse effects.

Neuropathic Pain in Pancreatic Cancer: An Update of the Last Five Years

Pain is the main symptom of pancreatic cancer (pancreatic ductal adenocarcinoma, PDAC). Pain in pancreatic cancer may be visceral, somatic or neuropathic in origin. Pain is produced by tissue damage, inflammation, ductal obstruction and infiltration. Visceral nociceptive signals caused by damage to the upper abdominal viscera are carried along sympathetic fibers, which travel to the celiac plexus nerves and ganglia, which are found at the T12-L2 vertebral levels, anterolateral to the aorta near the celiac trunk. From here, the signals are transmitted through the splanchnic nerves to the T5-T12 dorsal root ganglia and then on to the higher centers of the central nervous system. Somatic and neuropathic pain may arise from tumor extension into the surrounding peritoneum, retroperitoneum and bones and, in the latter case, into the nerves, such as the lumbosacral plexus. It should also be noted that other types of pain might arise because of therapeutic interventions, such as post-chemoradiation syndromes, which cause mucositis and enteritis. Management with non-steroidal anti-inflammatory agents and narcotics was the mainstay of therapy. In recent years, celiac plexus blocks and neurolysis, as well as intrathecal therapies have been used to control severe pain, at times resulting in a decreased need for drugs, avoiding their unwanted side effects. Pain may impair the patient’s quality of life, negatively affecting patient outcome and resulting in increased psychological stress. Even after recognizing the negative effect of cancer pain on patient overall health, studies have shown that cancer pain is still undertreated. This review focuses on neuropathic pain, which is difficult to handle; thus, the most recent literature was reviewed in order to diagnose neuropathic pain and its management.

WITHDRAWN: Neuropathic Cancer Pain in Patients Treated With an EGFR-Inhibitor

This article has been withdrawn because of a publisher error. It should not have been posted.

The Role of Anti-Nerve Growth Factor Monoclonal Antibodies in the Control of Chronic Cancer and Non-Cancer Pain.

Nerve growth factor (NGF) belongs to the neurotrophin family and plays a fundamental role in the endurance of sensory and sympathetic neurons during embryogenesis. NGF, by interacting with tropomyosin receptor kinase A receptor (TrkA), modulates the pain pathway through the enhancement of the neurotrophic and nociceptor functions. Moreover, it has been demonstrated that NGF is upregulated in patients with chronic pain syndromes, which are difficult to treat. Thus, new non-pharmacological approaches, based on the use of different species-specific monoclonal antibodies (mAbs) targeting the NGF pathway, have been tested for the treatment of chronic pain in preclinical and clinical studies. With regard to preclinical investigations, anti-NGF mAbs have been used for the management of osteoarthritis (OA) and chronic low back pain animal models, with encouraging results. Moreover, anti-NGF mAb therapy is effective in animal models of neuropathic cancer pain. As regards patients with OA, although phase II and phase III clinical trials with tanezumab led to pain reduction, the safety was not observed in all these patients. Here, we review the preclinical and clinical studies on anti-NGF mAb therapy in chronic syndromes, dissect the role of NGF in pain transduction, and highlight the use of anti-NGF mAbs in humans.

The impact of a standardised ketamine step protocol for cancer neuropathic pain

Context Ketamine at sub-anesthetic doses is a potent analgesia. Its use in cancer pain remains equivocal with protocols varying in patient selection, starting dose, titration, duration of use and adjustment of co-analgesics. Objective To study the impact of a standardised Ketamine Step Protocol on cancer pain in a Palliative Care Unit (PCU). Methodology This is a prospective cohort study of a standardised Ketamine Step Protocol which was developed in a PCU for use in cancer pain. The subcutaneous ketamine infusion was standardised at a starting dose of 75 mg over 24 hours with Haloperidol 5 mg as prophylaxis against psycho-mimetic side effects. Incremental doses of ketamine followed the daily stepwise protocol. Result Of the 48 patients analysed, 41 (85.4%) had neuropathic cancer pain. The median Palliative Performance Scale score (PPSv2) was 40%. Mean Numerical Rating Score (NRS) improved from 6.74 to 2.61 (P < 0.0001) with a mean percentage reduction of 58.05%. The final mean daily ketamine dose needed to achieve stable pain control was 137.50 mg/day (±81.54). 31(62.5%) patients achieved pain control by day 3. The mean Morphine Equivalent Daily Dose (MEDD) reduction was from 130.34 mg to 107.33 mg (P < 0.002) with a percentage reduction of 18.85%. More than half of our patients completed the 5 d protocol with mild to moderate side effects not warranting urgent medical intervention nor termination of the ketamine protocol. Conclusion Use of a standardised Ketamine Step Protocol showed a statistically significant reduction in pain and MEDD in patients with predominantly neuropathic cancer pain. It also demonstrated a safe and effective method for opioid reduction after commencement of parenteral ketamine. Key Message How can a standardised ketamine protocol impact on cancer pain control? Our study shows that: Parenteral ketamine is a potent analgesic which significantly reduced pain in patients with cancer neuropathic pain. This study also demonstrated a safe and effective method for titration of opioids after parenteral ketamine is started. Concurrent use of psychotropics also helps to reduce psycho-mimetic side effects, increasing tolerability to ketamine.

Blockade of Spinal EphA4 Reduces Chronic Inflammatory Pain in Mice

ABSTRACT Background: Erythropoietin-producing hepatocellular (Ephs) receptor and their ligands, ephrins, orchestrate the induction of cell proliferation and migration, axonal guidance, synaptic genesis and synaptic plasticity in the central nervous system. Previous studies demonstrated that EphBs/ephrinBs participate in the pathophysiology of neuropathic pain, inflammatory pain and bone cancer pain, but the role of EphA4 in the regulation of pain in the spinal cord is unknown. Therefore, we explored the role of EphA4 receptor in regulating chronic inflammatory pain. Methods: We established a mouse model of chronic inflammatory pain through plantar injection of complete freund’s adjuvant (CFA) and assessed EphA4 expression in spinal cord by western blotting. EphA4 receptor was blocked by intrathecal injection of EphA4-Fc, an EphA4 antagonist, and pain behaviors were measured by assessing thermal hyperalgesia and mechanical allodynia. Finally, immunohistochemistry was performed to analyze the changes in the expression of Fos protein in spinal cord after blocking EphA4 receptor. Results: Plantar injection of CFA produced persistent thermal hyperalgesia and mechanical allodynia, which was accompanied by significant increases in spinal EphA4 and Fos expression. Blocking spinal EphA4 receptor suppressed CFA-induced pain behaviors and reduced the expression of Fos protein in spinal cord. Conclusions: Our study demonstrated that EphA4 receptor is involved in the generation and maintenance of CFA-induced chronic inflammatory pain and that blocking the spinal EphA4 receptor could relieve persistent pain behaviors in mice.

The efficacy of gabapentin combined with opioids for neuropathic cancer pain: a meta-analysis.

BackgroundMore than 30% of cancer patients experience neuropathic pain. Opioids, as standard pain-relief agents, cannot achieve satisfactory outcomes to treat neuropathic cancer pain due to drug resistance and side effects. Meanwhile, gabapentin, a third-generation anticonvulsant drug, has great potential in providing relief for neuropathic cancer pain. However, there is currently no sufficient evidence to support the efficacy of a combination of gabapentin and opioids in ameliorating neuropathic cancer pain. Hence, the aim of the present study was to explore the analgesic efficacy of gabapentin combined with opioids in treating neuropathic cancer pain.MethodsPubMed, EMBASE, and Web of Science (Web of Knowledge) were searched for randomized controlled trials and prospective studies via the following keywords: “gabapentin”, “opioid”, “cancer”, and “neuropathic pain”. We used a scale of 0–10 (0 denoting no pain and 10 denoting the worst pain imaginable) to estimate pain intensity and utilized Review Manager 5.3 and Stata12 to analyze data.ResultsSeven studies meeting our criterion were selected from 110 records that were primarily searched. The mean difference of pooled pain intensity and the 95% confidence interval (CI) was –1.75 (–2.44, –1.07) (P value <0.00001; treatment group versus control group or time to outcome assessment versus baseline). The pain intensity of cancer patients after a combined treatment of gabapentin and opioids was significantly lower than that of patients receiving opioids alone.ConclusionsOur meta-analysis showed that gabapentin combined with opioids effectively alleviated neuropathic cancer pain compared with that of opioids alone.

The Burden of Cancer-related Neuropathic Pain: A Multi-centric Cross-sectional Observational Study from North India.

Introduction:Neuropathic cancer pain is a common consequence of cancer itself and anti-cancer treatments. It is a complex phenomenon, often underdiagnosed by physicians or underreported by patients. Its diagnosis and management are usually more challenging than nociceptive pain. There is a dearth of epidemiological evidence for neuropathic pain in cancer patients in India. Screening questionnaires serve as a quick guide to identify potential cases of neuropathic pain. The aim of the present study was to identify the burden of cancer-related neuropathic pain using the Self-reported version of the Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) pain scale.Methodology:This was a cross-sectional, observational, multi-centric study conducted at three hospitals in North India. From January 2017 to October 2017, patients attending pain clinic were screened for participation in the study. Adults aged ≥18 years and experiencing the pain of oncologic origin were eligible to participate in the study if they provided informed consent. S-LANSS questionnaire was used to screen patients with neuropathic pain.Results:From a total of 261 patients, who were enrolled in the study, 56.7% were male and their mean age was 50.87 (18–80) years. Fifty-four percent patients had pain with predominantly neuropathic component (S-LANSS score ≥10).Conclusion:High burden of neuropathic cancer pain has been observed in outpatient palliative care settings. Early diagnosis of neuropathic pain through screening questionnaires can serve as a quick guide for physicians in resource-constrained settings. This will allow identification of the neuropathic component of pain in patients suffering with mixed pain.

Nauka o medicinskoj marihuani i izazovi u istraživanju

Endocannabinoids are lipid-based retrograde neurotransmitters that bind to cannabinoid receptors, two of which are currently described: CB1 and CB2. The two main active components of cannabis are tetrahydrocannabinol (THC) and cannabidiol (CBD), have differing binding affinities to the receptors, allowing them to mediate different systemic effects as well as modulate each other's effects. Due to these varied properties, the therapeutic effect of marijuana is directly correlated with the THC:CBD ratio in a particular formulation. Current FDA-approved synthetic and cannabis-derived products are indicated for the treatment of nausea induced by chemotherapy, seizure disorders, and anorexia in AIDS patients. Regarding the treatment of chronic neuropathic pain and cancer pain, research has shown a low-to moderate quality evidence for use of cannabinoids, but greatly promising in providing alternatives to opioids. Challenges in medical research on cannabis remain, particularly in terms of inconsistent chemical composition and sourcing, small sample sizes, poor controls, and short duration of trials. Major medical institutions call for more thorough research and further investigation of marijuana safety and efficacy.

Editorial introductions

Current Opinion in Supportive and Palliative Care was launched in 2007. It is one of a successful series of review journals whose unique format is designed to provide a systematic and critical assessment of the literature as presented in the many primary journals. The fields of supportive and palliative care are divided into 12 sections that are reviewed once a year. Each section is assigned a Section Editor, a leading authority in the area, who identifies the most important topics at that time. Here we are pleased to introduce the Journal's Section Editors for this issue. SECTION EDITORS Aminah JatoiAminah JatoiDr Aminah Jatoi is the Betty J. Foust, M.D. and Parents’ Professor of Oncology at the Mayo Clinic in Rochester, Minnesota, USA. A practicing medical oncologist, she has been interested in symptom control research in cancer patients for over 20 years. She holds a special interest in cancer-associated weight loss, having completed a three-year fellowship in clinical nutrition. She is the author of more than 350 publications. Dr Jatoi has received research funding from multiple sources, including the United States’ National Cancer Institute. Barry J.A. LairdBarry J.A. LairdBarry J.A. Laird graduated in medicine from the University of Glasgow, UK, in 1997 and completed higher specialist training in palliative medicine in 2009. During his training in palliative medicine, he was awarded a National Cancer Research Institute Fellowship and joined the academic palliative medicine department at the University of Edinburgh, UK, with Professor Marie Fallon. He completed his MD in cancer induced bone pain and neuropathic cancer pain in 2009 and was then awarded a fellowship from the European Palliative Care Research Centre (PRC), working with Professor Stein Kaasa. His interest in cachexia was nurtured by the late Professor Kenneth Fearon. He currently holds positions as a Senior Lecturer in Palliative Medicine at the University of Edinburgh and a consultant in palliative medicine in St Columba's Hospice, UK. His research interests are focused around symptoms in life-limiting illness and the role of palliative care in optimising the care of malignant (lung and pancreatic cancer) and non-malignant disease. He leads a research programme examining the systemic inflammatory response in cachexia, symptom genesis and prognosis in cancer. He has published over 70 papers and is the Chief Investigator and the Principal Investigator of clinical trials in symptomatology and treatment.

Between-group difference in mean values or changes in pain intensity? Evaluating the distribution of change from baseline in a neuropathic cancer pain clinical trial.

Between-group difference in mean values or changes in pain intensity? Evaluating the distribution of change from baseline in a neuropathic cancer pain clinical trial.

Neuropathic pain: clinical classification and assessment in patients with pain due to cancer.

Neuropathic cancer pain (NcP) is associated with worse treatment responses and specific therapy indications, but a standardized clinical diagnosis of NcP is still lacking. This is a prospective observational study on outpatients with cancer, comparing different clinical approaches with NcP evaluation. A three-step assessment of NcP was performed using DN4 (cutoff of 4), palliative care physician Clinical Impression, including etiology and pain syndrome identification, and Retrospective Clinical Classification by a board of specialists with the IASP Neuropathic Pain Special Interest Group criteria. Neuropathic cancer pain classification was specifically referred to pain directly due to cancer. Three hundred fifty patients were assessed, and NcP prevalence was 20% (95% confidence interval [CI] 15.9%-24.6%), 36.9%, (95% CI 31.6%-42.1%), and 28.6% (95% CI 23.8%-33.9%) according to DN4, Clinical Impression, and Retrospective Clinical Classification, respectively. Cohen's kappa concordance coefficient between DN4 and Retrospective Clinical Classification was 0.57 (95% CI 0.47-0.67), indicating moderate concordance. Higher percentages of discordance were found for specific pain syndromes such as pain due to deep soft tissue infiltration and pain associated with tenesmus. Disagreement among clinicians accounted also for different NcP diagnoses and highlighted lack of homogeneous clinical criteria. Rigorous application of etiological and syndrome diagnosis to explain pain cause, associated with standardized diagnostic criteria and assessment of pain characteristics, that is also specific for the cancer pain condition could improve clinical classification of NcP.

A Practical Approach to Using Adjuvant Analgesics in Older Adults.

The adjuvant analgesics are a large and diverse group of drugs that were developed for primary indications other than pain and are potentially useful analgesics for one or more painful conditions. The "adjuvant" designation reflects their early use as opioid co-analgesics for cancer pain. During the past 3 decades, their role in pain management has changed with the advent of many new entities, emerging data from numerous analgesic trials, and growing clinical experience. Many of these drugs are now used as primary analgesics for specific types of chronic pain. With proper patient selection and cautious administration, they can potentially contribute meaningfully to the management of chronic pain in older adults. A practical approach categorizes the many adjuvant analgesics by broad indications: multipurpose drugs and drugs that target neuropathic pain, musculoskeletal pain, and cancer pain, respectively. This article reviews the status of the evidence supporting the analgesic potential of the adjuvant analgesics and discusses best practices in terms of drug selection and dosing. J Am Geriatr Soc 68:691-698, 2020.

Lemairamin, isolated from the Zanthoxylum plants, alleviates pain hypersensitivity via spinal α7 nicotinic acetylcholine receptors

Lemairamin (also known as wgx-50), is isolated from the pericarps of the Zanthoxylum plants. As an agonist of α7 nicotinic acetylcholine receptors (α7nAChRs), it can reduce neuroinflammation in Alzheimer’s disease. This study evaluated its antinociceptive effects in pain hypersensitivity and explored the underlying mechanisms. The data showed that subcutaneous lemairamin injection dose-dependently inhibited formalin-induced tonic pain but not acute nociception in mice and rats, while intrathecal lemairamin injection also dose-dependently produced mechanical antiallodynia in the ipsilateral hindpaws of neuropathic and bone cancer pain rats without affecting mechanical thresholds in the contralateral hindpaws. Multiple bi-daily lemairamin injections for 7 days did not induce mechanical antiallodynic tolerance in neuropathic rats. Moreover, the antinociceptive effects of lemairamin in formalin-induced tonic pain and mechanical antiallodynia in neuropathic pain were suppressed by the α7nAChR antagonist methyllycaconitine. In an α7nAChR antagonist-reversible manner, intrathecal lemairamin also stimulated spinal expression of IL-10 and β-endorphin, while lemairamin treatment induced IL-10 and β-endorphin expression in primary spinal microglial cells. In addition, intrathecal injection of a microglial activation inhibitor minocycline, anti-IL-10 antibody, anti-β-endorphin antiserum or μ-opioid receptor-preferred antagonist naloxone was all able to block lemairamin-induced mechanical antiallodynia in neuropathic pain. These data demonstrated that lemairamin could produce antinociception in pain hypersensitivity through the spinal IL-10/β-endorphin pathway following α7nAChR activation.

Indian Society for Study of Pain, Cancer Pain Special Interest Group Guidelines on Pharmacological Management of Cancer Pain (Part II).

The Indian Society for Study of Pain (ISSP), Cancer Pain Special Interest Group (SIG) guidelines on pharmacological management of cancer pain in adults provide a structured, stepwise approach, which will help to improve the management of cancer pain and to provide the patients with a minimally acceptable quality of life. The guidelines have been developed based on the available literature and evidence, to suit the needs, patient population, and situations in India. A questionnaire, based on the key elements of each sub draft addressing certain inconclusive areas where evidence was lacking, was made available on the ISSP website and circulated by e-mail to all the ISSP and Indian Association of Palliative Care members. We recommend that analgesics for cancer pain management should follow the World Health Organization 3-step analgesic ladder appropriate for the severity of pain. The use of paracetamol and nonsteroidal anti-inflammatory drugs alone or in combination with opioids for mild-to-moderate pain should be used. For mild-to-moderate pain, weak opioids such as tramadol, tapentadol, and codeine can be given in combination with nonopioid analgesics. We recommend morphine as the opioid of the first choice for moderate-to-severe cancer pain. Sustained-release formulations can be started 12 hourly, once the effective 24 h dose with immediate-release morphine is established. Opioid switch or rotation should be considered if there is inadequate analgesia or intolerable side effects. For opioid-induced respiratory depression, μ receptor antagonists (e.g. naloxone) must be used promptly. Antidepressants and/or anticonvulsants should be used to treat neuropathic cancer pain, and the dose should be titrated according to the clinical response and side effects. External beam radiotherapy should be offered to all patients with painful metastatic bone pain. There is evidence on use of ketamine in cancer neuropathic pain, but with no beneficial effect, thus, it is not recommended.

Indian Society for Study of Pain, Cancer Pain Special Interest Group Guidelines on Pharmacological Management of Cancer Pain (Part III).

The Indian Society for Study of Pain (ISSP), Cancer Pain Special Interest Group, guidelines on pharmacological management of cancer pain in adults provide a structured, step-wise approach which will help to improve the management of cancer pain and to provide patients with a minimally acceptable quality of life. The guidelines have been developed based on the available literature and evidence, to suit the needs, patient population, and situations in India. A questionnaire based on the key elements of each sub draft addressing certain inconclusive areas where evidence was lacking, was made available on the ISSP website and circulated by E-mail to all the ISSP and Indian Association of Palliative Care members. Antidepressants and/or anticonvulsants should be used to treat neuropathic cancer pain and the dose should be titrated according to the clinical response and side effects. External beam radiotherapy should be offered to all patients with painful metastatic bone pain. There is evidence on the use of ketamine in cancer neuropathic pain, but with no beneficial effect, thus it is not recommended.

Editorial introductions

Editorial introductions

Predictors of duloxetine response in patients with neuropathic cancer pain: a secondary analysis of a randomized controlled trial-JORTC-PAL08 (DIRECT) study.

Duloxetine has some effect against cancer neuropathic pain (CNP); however, predictors of duloxetine response are unclear. This study sought to identify predictors of duloxetine response in patients with CNP. Patients (N = 70) with CNP unresponsive to or intolerant of opioid-pregabalin combination therapy, with a brief pain inventory-short form (BPI-SF) Item 5 score (average pain) ≥ 4, and with a total hospital anxiety and depression scale score < 20, were randomized to a duloxetine or a placebo group. Multiple linear regression analysis was conducted to identify predictors of duloxetine response as a secondary analysis with the change in the average pain score on day 10 from day 0 as the dependent variable, and the following five covariates; baseline (day 0) average pain score, baseline opioid dose, continuation/discontinuation of pregabalin, and items 20 and 21 score of the short-form McGill pain questionnaire 2 (SF-MPQ-2) as independent variables. Of the four domains (continuous pain, intermittent pain, neuropathic pain, and affective descriptors) score of SF-MPQ-2 on day 0, significant differences were observed in the neuropathic pain domain (p = 0.040) in change on the average pain between day 10 and day 0 in the duloxetine group. Multiple linear regression analysis revealed that patients with a high score for SF-MPQ-2 Item 21 (tingling pain) on day 0 had a significantly greater change in average pain between day 10 and day 0 (p = 0.046). Patients with a high score for SF-MPQ-2 Item 21 might benefit more from duloxetine.