Interventional pain treatments for cancer pain

Sympathetic nerve blocks for persistent pain in adults with inoperable abdominopelvic cancer

BACKGROUND

Persistent visceral pain is an unpleasant sensation coming from one or more organs within the body. Visceral pain is a common symptom in those with advanced cancer. Interventional procedures, such as neurolytic sympathetic nerve blocks, have been suggested as additional treatments that may play a part in optimising pain management for individuals with this condition.

OBJECTIVES

To evaluate the benefits and harms of neurolytic sympathetic nerve blocks for persistent visceral pain in adults with inoperable abdominopelvic cancer compared to standard care or placebo and comparing single blocks to combination blocks.

SEARCH METHODS

We searched the following databases without language restrictions on 19 October 2022 and ran a top-up search on 31 October 2023: CENTRAL; MEDLINE via Ovid; Embase via Ovid; LILACS. We searched trial registers without language restrictions on 2 November 2022: ClinicalTrials.gov; WHO International Clinical Trials Registry Platform (ICTRP). We searched grey literature, checked reference lists of reviews and retrieved articles for additional studies, and performed citation searches on key articles. We also contacted experts in the field for unpublished and ongoing trials. Our trial protocol was preregistered in the Cochrane Database of Systematic Reviews on 21 October 2022.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) comparing any sympathetic nerve block targeting sites commonly used to treat abdominal pelvic pain from inoperable malignancies in adults to standard care or placebo.

DATA COLLECTION AND ANALYSIS

We independently selected trials based on predefined inclusion criteria, resolving any differences via adjudication with a third review author. We used a random-effects model as some heterogeneity was expected between the studies due to differences in the interventions being assessed and malignancy types included in the study population. We chose three primary outcomes and four secondary outcomes of interest. We sought consumer input to refine our review outcomes and assessed extracted data using Cochrane's risk of bias 2 tool (RoB 2). We assessed the certainty of evidence using the GRADE system.

MAIN RESULTS

We included 17 studies with 1025 participants in this review. Fifteen studies with a total of 951 participants contributed to the quantitative analysis. Single block versus standard care Primary outcomes No included studies reported our primary outcome, 'Proportion of participants reporting no worse than mild pain after treatment at 14 days'. The evidence is very uncertain about the effect of sympathetic nerve blocks on reducing pain to no worse than mild pain at 14 days when compared to standard care due to insufficient data (very low-certainty evidence). Sympathetic nerve blocks may provide small to 'little to no' improvement in quality of life (QOL) scores at 14 days after treatment when compared to standard care, but the evidence is very uncertain (standardised mean difference (SMD) -0.73, 95% confidence interval (CI) -1.70 to 0.25; I² = 87%; 4 studies, 150 participants; very low-certainty evidence). The evidence is very uncertain about the risk of serious adverse events as defined in our review as only one study contributed data to this outcome. Sympathetic nerve blocks may have an 'increased risk' to 'no additional risk' of harm compared with standard care (very low-certainty evidence). Secondary outcomes Sympathetic nerve blocks showed a small to 'little to no' effect on participant-reported pain scores at 14 days using a 0 to 10 visual analogue scale (VAS) for pain compared with standard care, but the evidence is very uncertain (mean difference (MD) -0.44, 95% CI -0.98 to 0.11; I² = 56%; 5 studies, 214 participants; very low-certainty evidence). There may be a 'moderate to large' to 'little to no' reduction in daily consumption of opioids postprocedure at 14 days with sympathetic nerve blocks compared with standard care, but the evidence is very uncertain (change in daily consumption of opioids at 14 days as oral milligrams morphine equivalent (MME): MD -41.63 mg, 95% CI -78.54 mg to -4.72 mg; I² = 90%; 4 studies, 130 participants; very low-certainty evidence). The evidence is very uncertain about the effect of sympathetic nerve blocks on participant satisfaction with procedure at 0 to 7 days and time to need for retreatment or treatment effect failure (or both) due to insufficient data. Combination block versus single block Primary outcomes There is no evidence about the effect of combination sympathetic nerve blocks compared with single sympathetic nerve blocks on the proportion of participants reporting no worse than mild pain after treatment at 14 days because no studies reported this outcome. There may be a small to 'little to no' effect on QOL score at 14 days after treatment, but the evidence is very uncertain (very low-certainty evidence). The evidence is very uncertain about the risk of serious adverse events with combination sympathetic nerve blocks compared with single sympathetic nerve blocks due to limited reporting in the included studies (very low-certainty evidence). Secondary outcomes The evidence is very uncertain about the effect of combination sympathetic nerve blocks compared with single sympathetic nerve blocks on participant-reported pain score and change in daily consumption of opioids postprocedure, at 14 days. There may be a small to 'little to no' effect, but the evidence is very uncertain (very low-certainty evidence). There is no evidence about the effect on participant satisfaction with procedure at 0 to 7 days and time to need for retreatment or treatment effect failure (or both) due to these outcomes not being measured by the studies. Risk of bias The risk of bias was predominately high for most outcomes in most studies due to significant concerns regarding adequate blinding. Very few studies were deemed as low risk across all domains for any outcome.

AUTHORS' CONCLUSIONS

There is limited evidence to support or refute the use of sympathetic nerve blocks for persistent abdominopelvic pain due to inoperable malignancy. We are very uncertain about the effect of combination sympathetic nerve blocks compared with single sympathetic nerve blocks. The certainty of the evidence is very low and these findings should be interpreted with caution.

Risk Factors Associated with Postoperative Cerebrospinal Fluid Leaks After Intrathecal Drug Delivery System and an External Pump Implantation in Cancer Patients: A Retrospective Study

INTRODUCTION

To determine risk factors associated with postoperative cerebrospinal fluid leaks (CSFLs) after intrathecal drug delivery system (IDDS) and external pump implantation.

METHODS

The clinical data of 248 patients with advanced cancer who underwent IDDS implantation from January 2021 to December 2022 at the Department of Pain Medicine at the Hunan Cancer Hospital were retrospectively reviewed. Information regarding age, gender, height, weight, body mass index (BMI), tumour type, albumin levels, haemoglobin levels, history of diabetes and pre- and postoperative anti-tumour therapy was collected and analysed.

RESULTS

Postoperative CSFLs occurred in 7 of 231 patients (3.30%). Statistical analysis indicated that gender, age, height, weight, BMI, tumour type, albumin levels, haemoglobin levels, history of diabetes, pre- and postoperative chemotherapy, pre- and postoperative radiotherapy, preoperative immunotherapy and postoperative targeted therapy were not independent factors for CSFLs. Preoperative targeted therapy [odds ratio (OR): 16.64; 95% confidence interval (CI): 1.42, 195.56; P = 0.01] and postoperative immunotherapy (OR: 13.38; 95% CI: 1.60, 111.65; P = 0.017) were factors associated with an increased postoperative CSFL rate. Of the two locations where CSFLs can occur, the back (puncture site of catheter, n = 4) and the hypochondriac region (location of infusion port implanted, n = 3), back CSFLs occurred earlier than in the hypochondriac region (18.25 ± 6.45 vs 115 ± 62.02 days, P = 0.032).

CONCLUSION

Based on the data from our study, the timing of preoperative targeted therapy and postoperative immunotherapy should be considered to prevent the occurrence of CSFLs in cancer pain patients who have an IDDS and external pump.

Clinical Presentation and Management of Malignant Psoas Syndrome: A Scoping Review of Case Reports and Case Series

Malignant psoas syndrome (MPS) is a rare and underreported clinical syndrome that significantly impacts the quality of life of cancer patients through metastatic infiltration of the iliopsoas muscle. Patients suffering from MPS often present with painful hip flexion, loss of mobility, and immense pain in their legs and back. The current literature describing the clinical presentation, management, and prognosis of MPS is limited primarily to case reports and outdated literature reviews. There remains a gap in the current knowledge of MPS and in the management of this complex cancer-related pain syndrome. Thus, this scoping review aimed to map current case reports and case series on MPS for clinical presentation, treatment modalities, and resulting prognoses of MPS in late-stage cancer patients. A systemized search using the databases Embase and PubMed (Medline) was conducted to access case reports and case series published between January 1990 and October 2022 that met the study's inclusion criteria: (1) adult patients with metastatic cancer; (2) MPS symptoms secondary to infiltration of iliopsoas; (3) clinical presentation, treatment modality, and prognosis; and (4) English-language text. Our search strategy yielded 1926 citations. After removing 629 duplicates, 1,283 reports were excluded due to failure to meet eligibility criteria (n=1,271) or inaccessibility (n=12). Using the JBI appraisal tools for case reports and case series, a total of 14 articles remained for the final review. With histories of either genitourinary, hepatic, gastric, or skin cancer, each case reported new onset intense pain in the legs, back, abdomen, or pelvis with associated symptoms such as flexion of the hip or gait disorder. A computerized tomography (CT) scan, magnetic resonance imaging (MRI), or positron emission tomography (PET) scan typically confirmed metastasis into the iliopsoas causing these symptoms, which suggested MPS. Each case utilized two to seven different pain management strategies to alleviate MPS symptoms. Many cases first used opioids for pain relief. Following a necessitated increase in morphine equivalent daily dose, a subsequent increase in the strength of analgesic, change in route of administration, and integration of combination drug therapy were generally added to the treatment regime. Many cases reported successful management of symptoms through utilizing methadone, radiation therapy, botulinum toxin injection, increased opioid dosage, or epidural catheter administration of opioids. A unified clinical definition of MPS may be required to inform physicians of this syndrome to help support clinical decisions regarding treatments for patients. The studies indicated that a clearer guideline for treatment protocol may be warranted as most cases reported utilizing various treatment medication dosages and procedures with vastly differing results.

Multimodal locoregional procedures for cancer pain management: a literature review

Pain is the most common and fearsome symptom in cancer patients, particularly in the advanced stage of disease. In cancer pain management, the first option is represented by analgesic drugs, whereas surgery is rarely used. Prior to considering surgical intervention, less invasive locoregional procedures are available from the wide pain management arsenal. In this review article, comprehensive information about the most commonly used locoregional options available for treating cancer pain focusing on interventional radiology (neurolysis, augmentation techniques, and embolization) and interventional radiotherapy were provided, also highlighting the potential ways to increase the effectiveness of treatments.

Fluoroscopy-Guided Splanchnic Nerve Block for Cancer-Associated Pain

Pain associated with abdominal malignancies or metastasis can be very severe and can be intractable and resistant to conventional pharmacologic therapies. Typically, narcotics and non-narcotics are used in combination to alleviate the cancer pain, but these are often unsuccessful. Neurolysis and radio-frequency ablation of the celiac plexus and splanchnic nerves is being used with great success for management of the pain associated with abdominal malignancies with added advantages of improving quality of life, pain relief and decreased narcotic consumption. The tumor or associated lymphadenopathy may result in distortion of the celiac plexus anatomy, thus making it hard to reach the celiac plexus. In such cases, splanchnic nerve block can be employed with relative ease as compared to celiac plexus block. Given the nature of the debilitating pain associated with these conditions and inadequate pain relief with narcotics, these blocks are a boon in disguise to such patients with altered anatomy. Post administration of the splanchnic block, the functioning and quality of life of patients with abdominal malignancies improve. Hence, these blocks can be used to decrease the morbidity associated with abdominal malignancies.

Interventional Treatment Modalities for Chronic Abdominal and Pelvic Visceral Pain

PURPOSE OF REVIEW

Chronic abdominal and pelvic visceral pain is an oftentimes difficult to treat pain condition that requires a multidisciplinary approach. This article specifically reviews the interventional treatment options for pain resulting from visceral abdominal and pelvic pain.

RECENT FINDINGS

Sympathetic nerve blocks are the main interventional option for the treatment of chronic abdominal and pelvic visceral pain. Initially, nerve blocks are performed, and subsequently, neurolytic injections (alcohol or phenol) are longer term options. This review describes different techniques for sympathetic blockade. Neuromodulation is a potential option via dorsal column stimulation or dorsal root ganglion stimulation. Finally, intrathecal drug delivery is sometimes appropriate for refractory cases. This paper will review interventional options for the treatment of chronic abdominal and pelvic visceral pain.

Opioid Therapy in Cancer Patients and Survivors at Risk of Addiction, Misuse or Complex Dependency

A clinical conundrum can occur when a patient with active opioid use disorder (OUD) or at elevated risk for the condition presents with cancer and related painful symptoms. Despite earlier beliefs that cancer patients were relatively unaffected by opioid misuse, it appears that cancer patients have similar risks as the general population for OUD but are more likely to need and take opioids. Treating such patients requires an individualized approach, informed consent, and a shared decision-making model. Tools exist to help stratify patients for risk of OUD. While improved clinician education in pain control is needed, patients too need to be better informed about the risks and benefits of opioids. Patients may fear pain more than OUD, but opioids are not always the most effective pain reliever for a given patient and some patients do not tolerate or want to take opioids. The association of OUD with mental health disorders (dual diagnosis) can also complicate delivery of care as patients with mental health issues may be less adherent to treatment and may use opioids for “chemical coping” as much as for pain control.

Interventional Treatments for Cancer Pain

Interventional pain management is a subspecialty of medicine devoted to the use of invasive techniques such as joint injections, nerve blocks/or neurolysis, neuromodulation, and epidural and selective nerve blocks to provide diagnosis and treatment of pain syndromes unresponsive to conventional medical management.

Lung Cancer Cell-Derived Exosomal let-7d-5p Down-Regulates OPRM1 to Promote Cancer-Induced Bone Pain

Cancer-induced bone pain (CIBP) is the pain caused by metastasis of malignant tumors to the bone, accounting for more than half of all chronic cancer pain, which seriously affects the quality of life among tumor patients. Up to 40% of patients with advanced lung cancer suffer from CIBP. MicroRNA (miRNA) transfers between cells through exosomes, mediates cell-to-cell communication, and performs various biological functions. Studies have shown that miRNAs secreted by cancer can modify the tumor microenvironment, but whether exosome-mediated miRNA transfer plays a role in CIBP is still unknown. In this study, the expression levels of 15 miRNAs in exosomes derived A549 cells and 18 miRNAs in exosomes derived NCI-H1299 cells were significantly up-regulated, and qRT-PCR further confirmed that the level of let-7d-5p was increased most considerably. In vitro, exosomal let-7d-5p (EXO let-7d-5p) can be taken up by dorsal root ganglion (DRG) neurons and inhibit the protein level of the target gene opioid receptor mu 1 (OPRM1). EXO let-7d-5p was further confirmed to be involved in the generation and maintenance of CIBP in vivo. Our findings clarify the molecular mechanism of CIBP caused by the inhibition of OPRM1 by EXO let-7d-5p, providing new clues and intervention targets for the prevention and treatment of CIBP.

A Comprehensive Update of the Superior Hypogastric Block for the Management of Chronic Pelvic Pain

PURPOSE OF REVIEW

This is a comprehensive review of the superior hypogastric block for the management of chronic pelvic pain. It reviews the background, including etiology, epidemiology, and current treatment available for chronic pelvic pain. It then presents the superior hypogastric block and reviews the seminal and most recent evidence about its use in chronic pelvic pain.

RECENT FINDINGS

Several definitions exist for chronic pelvic pain (CPP), making the diagnosis more challenging for the clinician; however, they commonly describe continuous pain lasting 6 months in the pelvis, with an overwhelming majority of patients being reproductive-aged women. This pain is often one of mechanical, inflammatory, or neuropathic. It is generally underdiagnosed and affects anywhere between 5 and 26% of women. The diagnosis of chronic pelvic pain is clinical, consisting of mainly of a thorough history and physical and ruling out other causes. The pathophysiology is often endometriosis (70%) and also includes PID, adhesions, adenomyosis, uterine fibroids, chronic processes of the GI and urinary tracts, as well as pelvic-intrinsic musculoskeletal causes. Treatment includes physical therapy, cognitive behavioral therapy, and oral and parenteral opioids. Interventional techniques provide an added tier of treatment and may help to reduce the requirement for chronic opioid use. Superior hypogastric plexus block is one of the available interventional techniques; first described in 1990, it has been shown to provide long-lasting relief in 50-70% of patients who underwent the procedure. Two approaches described so far, both under fluoroscopy, have seen similar results. More recently, ultrasound and CT-guided procedures have also been described with similar success. The injectate includes local anesthetic, steroids, and neurolytic agents such as phenol or ethanol. CPP is a common debilitating condition. It is diagnosed clinically and is underdiagnosed globally. Current treatments can be helpful at times but may fall short of satisfactory pain relief. Interventional techniques provide an added layer of treatment as well as reduce the requirement for opioids. Superior hypogastric plexus block provides long-lasting relief in many patients, regardless of approach. Evidence level is limited, and further RCTs could help provide better tools for evaluation and patient selection.

Reasons for failure to perform interventional pain procedures in cancer patients: an analysis of pain clinic consultations

Background

Interventional pain procedures (IPPs) may be necessary for some cancer patients when conservative treatment fails. However, many IPPs are often delayed or cancelled for cancer patients who are referred to the pain clinic.

Methods

We retrospectively analyzed the reasons for such cancellations to identify clinically avoidable causes of the delay in IPP.

Results

We enrolled 350 cancer patients who were referred to our pain clinic for an IPP between March 2016 and February 2018. There were 213 (60.9%) cases that were cancelled, among which 115 (54%) cases were potentially avoidable and 98 (46%) were unavoidable. The most common reasons for cancellation were patient-derived factors, which accounted for 85 (39.9%) cases. Patient refusal was a common reason for cancellation, with 33 (15.5%) cases attributed to this cause. The primary avoidable causes of cancellation were a recommendation that the patient continue with their current pharmacological pain treatment, conflict with another planned treatment, and pain characteristics that were not suitable for an IPP. Together, these accounted for 76.5% of all avoidable cancellations.

Conclusions

Comprehensive and accurate pain assessments before IPP may result in more favorable outcomes for the efficient use of medical resource and effective pain relief in cancer patients.

Prescription Pattern of Drugs Used for Neuropathic Pain and Adherence to NeuPSIG Guidelines in Cancer

Objective

The objective of the present research was to evaluate the prescription pattern of the drugs used in the pharmacological treatment of cancer-related neuropathic pain (CRNP) and to assess the adherence of the physicians to the Neuropathic Pain Special Interest Group (NeuPSIG) Guidelines.

Materials and Methods

This was a cross-sectional, observational study where patients who presented to the pain and palliative care outpatient clinic of the tertiary care hospital with CRNP were prospectively recruited. Participants were screened for neuropathic pain using DN4 questionnaire. Demographic details, diagnosis, medication details, and adherence to NeuPSIG guidelines were assessed using a validated questionnaire.

Results

Of 300 patients screened, 64% were male and 36% were female, with a mean age of 48.26 ± 13.05 years. The predominant symptoms found were pin-and-needle sensation (99%) followed by tingling sensation (98.66%). The most common diagnosis was head-and-neck cancers (37.3%) followed by bone cancers (17.3%) and lung cancers (15.3%). Among the first-line drugs recommended in NeuPSIG for CRNP, pregabalin (78.7%) was the most common drug prescribed followed by amitriptyline (67%). The most common co-prescribed drugs were acid suppressants drugs (50.7%). Tapentadol, which is not part of the NeuPSIG guidelines, was prescribed on 51 occasions for neuropathic pain. Underdosing was observed in 272 prescriptions. Only 12 prescriptions completely adhered, while 275 had partial, and 13 prescriptions had poor adherence to NeuPSIG guidelines.

Conclusion

The most commonly used drugs in the treatment of CRNP were pregabalin and amitriptyline. Most physician partially or did not adhere to the NeuPSIG guideline in the management of CRNP.

Non-Operating Room Anesthesia: Patient Selection and Special Considerations

Non-operating room anesthesia (NORA) represents a growing field of medicine with an increasing trend in the number of cases performed over the previous decade. As a result, anesthesia providers will need to enhance their familiarity with the resources, personnel, and environment outside of the operating room. Anesthesia delivery in NORA settings should be held with the same high-quality standards as that within the operating room. This review looks at special considerations in patient selection and the preoperative, intraoperative, and postoperative periods. In addition, there is a discussion on the unique aspects of specific NORA areas and the considerations that come with them.

Computed tomography-guided paravertebral doxorubicin injection for refractory pain in patients with spinal metastases: Two case reports

RATIONALE

Diagnosing and treating refractory cancer pain have become standardized and effective procedures with guidance from the Expert Consensus on Refractory Cancer Pain released in 2017 by the Committee of Rehabilitation and Palliative Care of China. Doxorubicin has been used for perineural injection in the treatment of chronic non-cancer pain owing to its retrograde sensory ganglion resection effect. Our study reports a new fourth-ladder treatment for cancer pain: CT-guided paravertebral doxorubicin injection for patients with refractory cancer pain caused by paraspinal metastasis.

PATIENT CONCERNS

A 48-year-old female and a 47-year-old male patients suffered from refractory cancer pain over the past months. They had both undergone surgical tumor resection, chemotherapy, and precision radiotherapy but result in limited analgesic effect. The daily oral morphine dosage was around 60 to 100 mg and rescue analgesic methods had been used at the time.

DIAGNOSES

Refractory cancer pain in 2 patients with renal cancer and hepatobiliary adenocarcinoma.

INTERVENTIONS

The patients both received computed tomography (CT)-guided 1 mL of 0.5% doxorubicin paravertebral injection at each affected nerve root segments.

OUTCOMES

The Visual Analog Scale and Douleur Neuropathique four Questions were used for 6-month follow-up, and the analgesic requirement was also recorded. The patients enjoyed satisfactory analgesia for up to 6 months without adverse reaction. In addition, the oral opioid analgesic doses were significantly reduced after the neurolytic block.

LESSONS

The CT-guided paravertebral doxorubicin injection was an effective fourth-step analgesic interventional technology that allowed our 2 patients with refractory cancer pain to maintain satisfactory analgesia. This analgesia method taken at an appropriate stage, according to the latest analgesic concept, results in good analgesia and opioid use reduction. Also, with the imaging guidance, only a small amount of neurolytic agent is needed to achieve analgesia in a precise and safe way.

Interventional treatments for metastatic bone cancer pain

Metastatic bone cancer pain may cause significant morbidity among the cancer patient population. Painful bone lesions are challenging to manage due to the aggressive pathophysiology of the pain generator involved. The WHO's approach to cancer pain treatment involves the use of a three-step ladder which provides a guideline for clinicians to treat patients who struggle from cancer pain syndromes. It is possible that this ladder is no longer helpful for patients who continue to fail oral or transdermal medication options. A fourth step in the cancer pain ladder has been proposed to include interventional approaches to cancer pain management. This review will discuss opioid therapy, radium-223, denosumab and bisphosphonate therapy, but will primarily review the available interventional treatment options for metastatic bone cancer pain.

Sinomenine attenuates cancer-induced bone pain via suppressing microglial JAK2/STAT3 and neuronal CAMKII/CREB cascades in rat models

Cancer-induced bone pain is one of the most severe types of pathological pain, which often occurs in patients with advanced prostate, breast, and lung cancer. It is of great significance to improve the therapies of cancer-induced bone pain due to the opioids' side effects including addiction, sedation, pruritus, and vomiting. Sinomenine, a traditional Chinese medicine, showed obvious analgesic effects on a rat model of chronic inflammatory pain, but has never been proven to treat cancer-induced bone pain. In the present study, we investigated the analgesic effect of sinomenine after tumor cell implantation and specific cellular mechanisms in cancer-induced bone pain. Our results indicated that single administration of sinomenine significantly and dose-dependently alleviated mechanical allodynia in rats with cancer-induced bone pain and the effect lasted for 4 h. After tumor cell implantation, the protein levels of phosphorylated-Janus family tyrosine kinase 2 (p-JAK2), phosphorylated-signal transducers and activators of transcription 3 (p-STAT3), phosphorylated-Ca2+/calmodulin-dependent protein kinase II (p-CAMKII), and phosphorylated-cyclic adenosine monophosphate response element-binding protein (p-CREB) were persistently up-regulated in the spinal cord horn. Chronic intraperitoneal treatment with sinomenine markedly suppressed the activation of microglia and effectively inhibited the expression of JAK2/STAT3 and CAMKII/CREB signaling pathways. We are the first to reveal that up-regulation of microglial JAK2/STAT3 pathway are involved in the development and maintenance of cancer-induced bone pain. Moreover, our investigation provides the first evidence that sinomenine alleviates cancer-induced bone pain by inhibiting microglial JAK2/STAT3 and neuronal CAMKII/CREB cascades.

The Role of Spinal GABAB Receptors in Cancer-Induced Bone Pain in Rats

Cancer-induced bone pain (CIBP) remains a major challenge in advanced cancer patients because of our lack of understanding of its mechanisms. Previous studies have shown the vital role of γ-aminobutyric acid B receptors (GABABRs) in regulating nociception and various neuropathic pain models have shown diminished activity of GABABRs. However, the role of spinal GABABRs in CIBP remains largely unknown. In this study, we investigated the specific cellular mechanisms of GABABRs in the development and maintenance of CIBP in rats. Our behavioral results show that acute as well as chronic intrathecal treatment with baclofen, a GABABR agonist, significantly attenuated CIBP-induced mechanical allodynia and ambulatory pain. The expression levels of GABABRs were significantly decreased in a time-dependent manner and colocalized mostly with neurons and a minority with astrocytes and microglia. Chronic treatment with baclofen restored the expression of GABABRs and markedly inhibited the activation of cyclic adenosine monophosphate (cAMP)-dependent protein kinase and the cAMP-response element-binding protein signaling pathway.

PERSPECTIVE

Our findings provide, to our knowledge, the first evidence that downregulation of GABABRs contribute to the development and maintenance of CIBP and restored diminished GABABRs attenuate CIBP-induced pain behaviors at least partially by inhibiting the protein kinase/cAMP-response element-binding protein signaling pathway. Therefore, spinal GABABR may become a potential therapeutic target for the management of CIBP.

Reporting of Design Features and Analysis Details in Randomized Clinical Trials of Procedural Treatments for Cancer Pain: An ACTTION Systematic Review

BACKGROUND AND OBJECTIVES

The objective of this study was to assess the reporting of randomized clinical trials investigating procedural treatments (eg, nerve blocks, targeted drug delivery) for cancer pain, with a focus on aspects that are particularly challenging in these trials.

METHODS

This article presents results from a systematic review of reporting of randomized clinical trials of procedural interventions for cancer pain. Articles were identified by searching PubMed from 1966 to June 2014. Data related to quality of reporting are presented for early (1985-2004) and late periods (2005-2014).

RESULTS

A total of 35 published trials were included. Approximately two-thirds of the articles clearly indicated the level of blinding. Only 26% reported a primary outcome measure. Less than half explicitly reported the number of patients who completed the trial, and only 1 reported a method that was used to accommodate missing data. Almost one-third of articles included a responder analysis, all of which specified the definition of a responder.

CONCLUSIONS

The goal of highlighting these deficiencies in reporting is to promote transparent reporting of details affecting the completion and interpretation of procedural cancer pain trials so that their quality can be more easily evaluated.

Targeting glia for bone cancer pain

INTRODUCTION

Bone cancer pain (BCP) remains to be a clinical challenge with limited pharmaceutical interventions. Therefore, novel therapeutic targets for the management of BCP are in desperate need. Recently, a growing body of evidence has suggested that glial cells may play a pivotal role in the pathogenesis of BCP. Areas covered: This review summarizes the recent progress in the understanding of glia in BCP and reveals the potential therapeutic targets in glia for BCP treatment. Expert opinion: Pharmacological interventions inhibiting the activation of glial cells, suppressing glia-derived proinflammatory cytokines, cell surface receptors, and the intracellular signaling pathways may be beneficial for the pain management of advanced cancer patients. However, these pharmacological interventions should not disrupt the normal function of glia cells since they play a vital supportive and protective role in the central nervous system.

A New Perspective of Neuromyopathy to Explain Intractable Pancreatic Cancer Pains; Dry Needling as an Effective Adjunct to Neurolytic Blocks

We present a new perspective of neuromyopathy in pancreatic cancer pain (PCP) referral to bodywall; proposal of new rationale to include ultrasound guided dry needling (USGDN) of body wall muscles as an effective adjunct to neurolytic coeliac plexus block (NCPB) or splanchnic nerve radiofrequency ablation (SRF) for comprehensive interventional management. Methods: PCP response to SRF in 2 patients and NCPB in 3 patients was documented on numerical rating scale (NRS) on post procedure days 3 and 15. If the residual pain was >5 NRS on day 15, USGDN of abdominal and back muscles was started on a thrice weekly basis. The response to USGDN documented on day 30 after approximately 6 sessions of DN, showed a significant pain reduction (0-2 NRS) with 50% reduction of pre-treatment opioid consumption. This was sustained at 6 months or till their demise. Convergence of visceral and somatic nerves at the dorsal horn (viscerosomatic neurons) causes referral of visceral pain to the back and abdominal muscles. This leads to formation of myofascial trigger points (MTrPs) in the muscles which sets up a parallel network of sensitized peripheral and central motor nociceptive processing (neuromyopathy). USGDN specifically addressed the MTrPs that develop as an epiphenomenon of self-perpetuating neuromyopathy while SRF/NCPB, analgesics and neuromodulators could address only visceral nociceptive afferents (pain mediated through celiac plexus) which forms a meagre 10% of the total spinal cord afferent input. Thus, we conclude that combination of neuromyopathy and viscerosomatic convergence in PCP indicate a specific role for DN as an adjunct to SRF/NCPB in our patients

Features and Role of Minimally Invasive Palliative Procedures for Pain Management in Malignant Pelvic Diseases: A Review

Pain is a common and debilitating symptom in pelvic cancer diseases. Failure in controlling this pain through pharmacological approaches calls for employing multimodal management and invasive techniques. Various strategies are commonly used for this purpose, including palliative radiotherapy, epidural medications and intrathecal administration of analgesic and local anesthetic drugs with pumps, and neural or plexus blockade. This review focuses on the features of minimally invasive palliative procedures (MIPPs), such as radiofrequency ablation, laser-induced thermotherapy, cryoablation, irreversible electroporation, electrochemotherapy, microwave ablation, and cementoplasty as well as their role in palliation of cancer pelvic pain. Despite the evidence of effectiveness and safety of these interventions, there are still many barriers to accessing MIPPs, including the availability of trained staff, the lack of precise criteria of indication, and the high costs.

Evidence-based Clinical Practice Guidelines for Interventional Pain Management in Cancer Pain

Intractable cancer pain not amenable to standard oral or parenteral analgesics is a horrifying truth in 10-15% of patients. Interventional pain management techniques are an indispensable arsenal in pain physician's armamentarium for severe, intractable pain and can be broadly classified into neuroablative and neuromodulation techniques. An array of neurolytic techniques (chemical, thermal, or surgical) can be employed for ablation of individual nerve fibers, plexuses, or intrathecalneurolysis in patients with resistant pain and short life-expectancy. Neuraxial administration of drugs and spinal cord stimulation to modulate or alter the pain perception constitutes the most frequently employed neuromodulation techniques. Lately, there is a rising call for early introduction of interventional techniques in carefully selected patients simultaneously or even before starting strong opioids. After decades of empirical use, it is the need of the hour to head towards professionalism and standardization in order to secure credibility of specialization and those practicing it. Even though the interventional management has found a definite place in cancer pain, there is a dearth of evidence-based practice guidelines for interventional therapies in cancer pain. This may be because of paucity of good quality randomized controlled trials (RCTs) evaluating their safety and efficacy in cancer pain. Laying standardized guidelines based on existing and emerging evidence will act as a foundation step towards strengthening, credentialing, and dissemination of the specialty of interventional cancer pain management. This will also ensure an improved decision-making and quality of life (QoL) of the suffering patients.

Current perspectives on intrathecal drug delivery

Advances in intrathecal analgesia and intrathecal drug delivery systems have allowed for a range of medications to be used in the control of pain and spasticity. This technique allows for reduced medication doses that can decrease the side effects typically associated with oral or parenteral drug delivery. Recent expert panel consensus guidelines have provided care paths in the treatment of nociceptive, neuropathic, and mixed pain syndromes. While the data for pain relief, adverse effect reduction, and cost-effectiveness with cancer pain control are compelling, the evidence is less clear for noncancer pain, other than spasticity. Physicians should be aware of mechanical, pharmacological, surgical, and patient-specific complications, including possible granuloma formation. Newer intrathecal drug delivery systems may allow for better safety and quality of life outcomes.

Bupivacaine administered intrathecally versus rectally in the management of intractable rectal cancer pain in palliative care

Background

Unacceptable adverse effects, contraindications to and/or ineffectiveness of World Health Organization step III “pain ladder” drugs causes needless suffering among a population of cancer patients. Successful management of severe cancer pain may require invasive treatment. However, a patient’s refusal of an invasive procedure necessitates that clinicians consider alternative options.

Objective

Intrathecal bupivacaine delivery as a viable treatment of intractable pain is well documented. There are no data on rectal bupivacaine use in cancer patients or in the treatment of cancer tenesmoid pain. This study aims to demonstrate that bupivacaine administered rectally could be a step in between the current treatment options for intractable cancer pain (conventional/conservative analgesia or invasive procedures), and to evaluate the effect of the mode of administration (intrathecal versus rectal) on the bupivacaine plasma concentration.

Cases

We present two Caucasian, elderly inpatients admitted to hospice due to intractable rectal/tenesmoid pain. The first case is a female with vulvar cancer, and malignant infiltration of the rectum/vagina. Bupivacaine was used intrathecally (0.25–0.5%, 1–2 mL every 6 hours). The second case is a female with ovarian cancer and malignant rectal infiltration. Bupivacaine was adminstered rectally (0.05–0.1%, 100 mL every 4.5–11 hours).

Methods

Total bupivacaine plasma concentrations were determined using the high-performance liquid chromatography-ultraviolet method.

Results

Effective pain control was achieved with intrathecal bupivacaine (0.077–0.154 mg·kg⁻¹) and bupivacaine in enema (1.820 mg·kg⁻¹). Intrathecal bupivacaine (0.5%, 2 mL) caused a drop in blood pressure; other side effects were absent in both cases. Total plasma bupivacaine concentrations following intrathecal and rectal bupivacaine application did not exceed 317.2 ng·mL⁻¹ and 235.7 ng·mL⁻¹, respectively. Bupivacaine elimination was slower after rectal than after intrathecal administration (t_½= 5.50 versus 2.02 hours, respectively).

Limitations

This study reports two cases only, and there could be inter-patient variation.

Conclusion

Bupivacaine in boluses administered intrathecally (0.25%, 2 mL) provided effective, safe analgesia in advanced cancer patients. Bupivacaine enema (100 mg·100 mL⁻¹) was shown to be a valuable option for control of end-of-life tenesmoid cancer pain.

Factors associated with outcome after superior hypogastric plexus neurolysis in cancer patients

OBJECTIVE

Superior hypogastric plexus neurolysis (SHP-N) has been shown in uncontrolled studies to provide intermediate-term benefit in a majority of patients with pain secondary to genitourinary, gynecologic, and colorectal cancers. The purpose of this is to determine factors associated with treatment outcome.

MATERIALS AND METHODS

Patients who underwent SHP-N after a positive prognostic block were identified based on diagnostic classification and procedural codes from databases at 2 large teaching hospitals. A host of demographic, clinical, and treatment factors were examined for their association with treatment success, which was defined as ≥50% pain relief lasting ≥1 month.

RESULTS

A total of 53.1% of 32 patients with sufficient medical records for analysis experienced a positive outcome. Those with a positive outcome were older (mean age 59.6 y, SD 13.1 vs. 47.8, SD 15.6; P=0.03), less likely to have pelvic pain (36.8% success rate, P=0.04), and more likely to have bladder cancer (88.9% success rate; P=0.01) than those with a negative outcome. In stratified analysis, female were more likely to have positive outcome if they did not have pelvic pain compared to those that did (P=0.008). This difference was not significant for males.

DISCUSSION

Selecting patients based on demographic and clinical variables may improve treatment outcomes for SHP-N. Larger, prospective studies are needed to confirm our results and better refine selection criteria better.

Management of pain in advanced disease

BACKGROUND

Pain is common in advanced malignancy but also prevalent in other non-malignant life-limiting diseases such as advanced heart disease; end stage renal failure and multiple sclerosis. Patients with renal or liver impairment need specific consideration, as most analgesics rely on either or both for their metabolism and excretion.

SOURCES OF DATA

Recent evidence-based guidelines and the systematic reviews that have informed their recommendations.

AREAS OF AGREEMENT

The principles of the WHO (World Health Organisation) analgesic ladder are commonly endorsed as a structured approach to the management of pain. For neuropathic pain, the efficacy of different agents is similar and choice of drug more guided by side effects, drug interactions and cost.

AREAS OF CONTROVERSY

Evidence supporting the WHO analgesic ladder is disputed and alternatives suggested, but no overwhelming evidence for an alternative approach exists to date.

GROWING POINTS

Alternative approaches to the WHO analgesic ladder, new analgesic agents, e.g. rapid onset oral/intranasal fentanyl.

An overview of treatment strategies for cancer pain with a focus on interventional strategies and techniques

SUMMARY As the incidence of cancer increases, considerations for pain treatments become more important and varied. While traditional views on pain therapy are successful in treating the majority of cancer-related pain, a continuum has developed to include interventional strategies in addition to pharmacologic management. Further improvements in understanding anatomy in the context of imaging and pathophysiology of cancer-pain syndromes direct our current interventional pain management options. We discuss the current interventional treatment options regularly used in the cancer-pain population.

Intercostal administration of liposomal bupivacaine as a prognostic nerve block prior to phenol neurolysis for intractable chest wall pain

Inadequate pain relief from systemic medications is common in patients with advanced malignancy. Chest wall pain secondary to tumor involvement of chest wall structures can be challenging to manage with systemic medications, and occasionally patients benefit from interventional procedures such as intercostal nerve blocks and neurolysis. In this report, the authors describe the case of a 58-year-old woman with advanced non-small cell lung cancer with tumor invasion into the third thoracic rib. After reaching maximum tolerated doses of transdermal fentanyl, oral hydromorphone, and oral ketamine, the patient elected for intercostal nerve blockade and neurolysis. Prognostic nerve blockade was performed using liposomal bupivacaine administered via intercostal approach. This formulation of bupivacaine provided an excellent prognostic blockade, which lasted for approximately 96 hours. This extended period of time allowed the patient to fully evaluate the prognostic blockade, prior to proceeding with neurolysis with phenol. This case suggests that liposomal bupivacaine may be a valuable adjunctive agent for prognostic blockade prior to neurolysis for cancer pain.

Interventional procedures for cancer pain management

OBJECTIVE

To describe types of interventional medical procedures its rationale use and benefits for a population with cancer assisted at a private hospital in São Paulo.

METHODS

Quantitative and descriptive cross-sectional study using data from patients submitted to interventional procedures between 2007 and 2008. We used descriptive and inferential statistics (frequency, mean, and t-test) to analyze data.

RESULTS

A total of 137 patients were submitted to interventional procedures for pain and, out of this total, 14 mentioned cancer-related pain. The mean pain intensity was 7.1 before the procedure and 1.3 after it. Reduction in pain intensity was statistically significant in this population (t=9.09; p=0.001). In almost 70% of patients (n=10) a reduction of 50% of the consumption of opioid a month after the procedure was realized.

CONCLUSION

These results are in accordance with the literature and support the efficacy of interventional procedures for several types of cancer pain.

Percutaneous dorsal root ganglion lysis with phenol for the treatment of pain associated with thoracic compression fracture

BACKGROUND

Symptomatic thoracic compression fracture is one of the most common causes of back pain in elderly. Although vertebroplasty is widely utilized in patients when conservative treatment fails, we introduced an alternative percutaneous technique for the treatment of thoracic compression pain.

METHODS

This in a retrospective study. The analysis was performed on 28 consecutive patients who underwent undergoing percutaneous dorsal root ganglion lysis with phenol for the treatment of pain associated with thoracic compression fracture. An acceptable treatment outcome was operationally defined as a pain intensity numerical rating scale (NRS) score of 3 or lower or EQ-5D index of 0.672 or higher. The primary outcome was pain relief and acceptable treatment outcome at 1 day, 1 week, 1 month, and 1 year.

RESULTS

Of the 28 cases treated with our procedures, the change in mean NRS score between baseline and one day was -2.5 (95 % CI -1.6 ~ -3.4, p < 0.001), between baseline and one week was -4.7 (-4.1 to -5.3, p < 0.001), between baseline and one month was -5.8 (-5.2 to -6.5, p < 0.001), and between baseline and one year was -6.3 (-5.6 to -7.1, p < 0.001). An acceptable treatment outcome was 14 % one day after the procedure, 46 % at one week, 72 % at one month, and 84 % at one year. Complication rate was 3.6 %.

CONCLUSIONS

For thoracic compression fracture patients, percutaneous dorsal root ganglion lysis with phenol is an effective, and safe alternative treatment method worth considering. Pain relief is fast and persists for one year.

Cancer-related neuropathic pain in out-patient oncology clinics: a European survey

Background

Although pain is frequently experienced by patients with cancer, it remains under-treated. The primary aim of this study was to estimate the prevalence of cancer-related neuropathic pain (CRNP) in patients with chronic pain who attended an outpatient clinic for standard care in Europe (irrespective of the reason or stage of the cancer). The secondary aims of this study were to characterise pain and cancer in patients with CRNP (including treatment) and to evaluate the usefulness of the painDETECT (PD-Q) screening tool to help physicians identify a potential neuropathic component of cancer-related pain.

Methods

An observational, non-interventional, cross-sectional, multi-centre study of adult patients with cancer using patient and physician case report forms (CRFs). Patients with CRNP were identified by physicians’ clinical assessments after examining the completed PD-Q.

Results

A total of 951 patients visiting outpatient clinics across Europe were enrolled in this study between August 2010 and July 2011. Of these, 310 patients (32.60%; 95% confidence interval 29.62, 35.58) were identified as having CRNP. Twenty-nine of 39 (74.4%) physicians who completed the CRF relating to the PD-Q considered it a useful tool to help detect CRNP in daily practice and 28 of 39 (71.8%) indicated that they would use this tool in the future for most or some of their patients. Data from physicians before and after review of the completed PD-Qs showed a shift in clinical opinion (either to positive CRNP diagnosis [yes] or negative CRNP diagnosis [no]) in respect of 142 patients; about half of which (74) were categorised with an initial diagnosis of unknown. Opinions also shifted from a no to a yes diagnosis in 10 patients and from a yes to a no diagnosis in 51 patients.

Conclusions

Approximately one-third of adults with cancer experiencing chronic pain attending outpatient clinics as part of routine care were considered to have CRNP in the opinion of the physicians after considering scores on the PD-Q. While physicians did not consider the PD-Q to be a useful tool for all patients, shifts in diagnosis before and after the use of this tool indicate that it may help physicians identify CRNP, especially where there is initial uncertainty.

Regional anesthesia and analgesia in critically ill patients: a systematic review

Regional anesthesia has become invaluable for the treatment of pain during and after a wide range of surgical procedures. However, its benefits in the nonsurgical setting have been less well studied. Regional anesthesia is an appealing modality for critically ill patients, providing focused and sustained pain control with beneficial systemic effect profiles. Indications for regional anesthesia in this patient group are not limited to surgical and postsurgical analgesia but expand to the management of trauma-related issues, medical conditions, and painful procedures at the bedside. Patients in the critical care unit present special challenges to the regional anesthesiologist, including coagulopathies, infections, immunocompromised states, sedation- and ventilation-associated problems, and factors potentially increasing the risk for systemic toxicity. This review is intended to evaluate the role of regional anesthesia in critically ill patients, to discuss potential benefits, and to provide a summary of the published evidence on the subject.

The modern pharmacology of paracetamol: therapeutic actions, mechanism of action, metabolism, toxicity and recent pharmacological findings

Paracetamol is used worldwide for its analgesic and antipyretic actions. It has a spectrum of action similar to that of NSAIDs and resembles particularly the COX-2 selective inhibitors. Paracetamol is, on average, a weaker analgesic than NSAIDs or COX-2 selective inhibitors but is often preferred because of its better tolerance. Despite the similarities to NSAIDs, the mode of action of paracetamol has been uncertain, but it is now generally accepted that it inhibits COX-1 and COX-2 through metabolism by the peroxidase function of these isoenzymes. This results in inhibition of phenoxyl radical formation from a critical tyrosine residue essential for the cyclooxygenase activity of COX-1 and COX-2 and prostaglandin (PG) synthesis. Paracetamol shows selectivity for inhibition of the synthesis of PGs and related factors when low levels of arachidonic acid and peroxides are available but conversely, it has little activity at substantial levels of arachidonic acid and peroxides. The result is that paracetamol does not suppress the severe inflammation of rheumatoid arthritis and acute gout but does inhibit the lesser inflammation resulting from extraction of teeth and is also active in a variety of inflammatory tests in experimental animals. Paracetamol often appears to have COX-2 selectivity. The apparent COX-2 selectivity of action of paracetamol is shown by its poor anti-platelet activity and good gastrointestinal tolerance. Unlike both non-selective NSAIDs and selective COX-2 inhibitors, paracetamol inhibits other peroxidase enzymes including myeloperoxidase. Inhibition of myeloperoxidase involves paracetamol oxidation and concomitant decreased formation of halogenating oxidants (e.g. hypochlorous acid, hypobromous acid) that may be associated with multiple inflammatory pathologies including atherosclerosis and rheumatic diseases. Paracetamol may, therefore, slow the development of these diseases. Paracetamol, NSAIDs and selective COX-2 inhibitors all have central and peripheral effects. As is the case with the NSAIDs, including the selective COX-2 inhibitors, the analgesic effects of paracetamol are reduced by inhibitors of many endogenous neurotransmitter systems including serotonergic, opioid and cannabinoid systems. There is considerable debate about the hepatotoxicity of therapeutic doses of paracetamol. Much of the toxicity may result from overuse of combinations of paracetamol with opioids which are widely used, particularly in USA.

One is the loneliest number: a review of the ganglion impar and its relation to pelvic pain syndromes

The ganglion impar is often overlooked as a component of the sympathetic nervous system. Despite its obscurity, this ganglion provides a pathway for neurons by accommodating postganglionic sympathetics, visceral afferents, and somatic fibers traveling to and from the pelvis. Its classic anatomic location as described in the 1720's held up until recently, with the current literature now revealing a great deal of anatomical variability. This variation becomes important when the ganglion impar is used as a treatment target for patients with chronic pelvic pain - its primary clinical implication. The aim of this review was to provide a better understanding of the anatomy of ganglion impar, accounting for variation in size, shape, and location. In addition, the clinical importance and treatment modalities associated with the ganglion impar are outlined.

Epidural methadone results in dose-dependent analgesia in cancer pain, further enhanced by epidural dexamethasone

Background:

This study was designed to evaluate the role of epidural methadone-lidocaine in cancer pain combined or not to epidural dexamethasone.

Methods:

In all, 72 cancer patients, 32- to 67-year-old were randomized to six groups (n=12) and prospectively studied to examine analgesia and adverse effects for 3 weeks. Patients received single-dose protocol epidural test drugs: Control group (CG) received epidural 40-mg lidocaine diluted to 10-ml volume with saline. Dexamethasone group (DG) 40-mg lidocaine plus 10-mg dexamethasone. The 2.5MetG 2.5-mg epidural methadone with 40-mg lidocaine; the 5MetG, 5-mg epidural methadone plus 40-mg lidocaine, the 7.5MetG, 7.5-mg epidural methadone plus 40-mg lidocaine and finally the 7.5Met-DexG, 7.5-mg methadone with 40-mg lidocaine and 10-mg dexamethasone.

Results:

Groups CG, DG and 2.5MetG were similar regarding analgesia and side effects. Patients from 5MetG and 7.5MetG took 3±1 and 5±1 days, respectively, to restart oral morphine. Patients from 7.5MetDG took 14±2 to restart oral morphine (P<0.001). Daily somnolence and appetite improved in the 7.5MetDG during 2-week evaluation (P<0.005). Fatigue improved for both DG and 7.5MetDG during 2-week evaluation (P<0.005). By the third week of evaluation, all patients were similar.

Conclusions:

Epidural methadone plus lidocaine resulted in dose-dependent analgesia, further improved by epidural dexamethasone, which also improved fatigue.

Revision and Validation of a Medication Assessment Tool for Chronic Cancer Pain Management

The medication assessment tool for cancer pain management (MAT-CP) measures the quality of medication use in relation to guidelines. The original MAT-CP was reviewed, modified and tested at a comprehensive cancer center in Jordan. The tool comprised 30 criteria covering six different aspects of pain management. Seventy patients were included, males 41 (59%), females 29 (41%), mean age 49 (range, 20-79) years. The overall level of adherence to guidelines was 78% with good inter-rater reliability (κ= 0.899). The tool's implementation showed opportunities for improvement in pain management at our institution. The MAT-CP was revised and validated for the first time outside Europe. This tool can be routinely used to assess and compare the quality of pain management in different institutions.

Inhibition of p38-MAPK signaling pathway attenuates breast cancer induced bone pain and disease progression in a murine model of cancer-induced bone pain

BACKGROUND

Mechanisms driving cancer-induced bone pain are poorly understood. A central factor implicated to be a key player in the process of tumorigenesis, osteoclastogenesis and nociception is p38 MAPK. We determined the role of p38 MAPK in a mouse model of breast cancer induced bone pain in which mixed osteolytic and osteoblastic remodeling occurs.

RESULTS

In cancer-treated mice, acute as well as chronic inhibition of p38 MAPK with SB203580 blocked flinching and guarding behaviors in a dose-dependent manner whereas no effect on thresholds to tactile stimuli was observed. Radiographic analyses of bones demonstrated that chronic inhibition of p38 MAPK reduced bone loss and incidence of spontaneous fracture in cancer-treated mice. Histological analysis of bones collected from mice treated with the p38 MAPK inhibitor showed complete absence of osteoblastic growth in the intramedullary space as well as significantly reduced tumor burden.

CONCLUSIONS

Blockade of non-evoked pain behaviors but not hypersensitivity suggests differences in the underlying mechanisms of specific components of the pain syndrome and a possibility to individualize aspects of pain management. While it is not known whether the role of p38 MAPK signaling can be expanded to other cancers, the data suggest a need for understanding molecular mechanisms and cellular events that initiate and maintain cancer-induced bone pain for effective management for both ongoing pain as well as breakthrough pain.

Bisphosphonates as radionuclide carriers for imaging or systemic therapy

Bisphosphonates (BP's), biologically stable analogs of naturally occurring pyrophosphates, became the treatment of choice for pathologic conditions characterized by increased osteoclast-mediated bone resorption, namely Paget's disease, osteoporosis and tumor bone disease. Moreover, the clinical success of BP's is also associated with their use in (99m)Tc-based radiopharmaceuticals for bone imaging. In addition to the successful delivery of (99m)Tc (γ-emitter) to bone, BP's have also been used to deliver β(-)-particle emitting radiometals (e.g.(153)Sm, (186/188)Re) for bone-pain palliation. The main goal of this Review is to update the most recent research efforts toward the synthesis, characterization and biological evaluation of novel BP-containing radiometal complexes and radiohalogenated compounds for diagnostic or therapeutic purposes. The structure and in vivo properties of those compounds will be discussed and compared to the clinically available ones, namely in terms of image quality and therapeutic effect. We will also mention briefly the use of BP's as carriers of multimodal nuclear and optical imaging probes.

Dimethyl sulfoxide and sodium bicarbonate in the treatment of refractory cancer pain

Pain is a major concern of cancer patients and a significant problem for therapy. Pain can become a predominant symptom in advanced cancers. In this open-label clinical study, the authors have treated 26 cancer patients who have been declared as terminal without the option of conventional treatment. These patients suffered from high levels of pain that was poorly managed by all available interventional approaches recommended by World Health Organization (WHO) guideline. The results indicate that intravenous infusion of dimethyl sulfoxide (DMSO) and sodium bicarbonate (SB) solution can be a viable, effective, and safe treatment for refractory pain in cancer patients. These patients had pain due to the disease progression and complication of chemotherapy and radiation. Moreover, the preliminary clinical outcome of 96-day follow-up suggests that the application of DMSO and SB solution intravenously could lead to better quality of life for patients with nontreatable terminal cancers. The data of this clinical observation indicates that further research and application of the DMSO and SB combination may help the development of an effective, safe, and inexpensive therapy to manage cancer pain.

Intrathecal neurolytic block in a patient with refractory cancer pain

We report the successful treatment of refractory cancer pain by bilateral intrathecal neurolysis using phenol-glycerol. A 60-year-old man had recurrent sigmoid cancer and metastases to the lumbar (L4-5) and sacral bones. He complained of refractory pain in the lower back and lower extremities despite high-dose opioid treatment based on the WHO ladder. On admission to our hospital, he received continuous intravenous infusion of morphine (7,000 mg/day) with ketamine (300 mg/day) and lidocaine (700 mg/day). Intravenous midazolam was required to treat extreme anxiety. Because of inadequate pain relief and severe drowsiness, intrathecal phenol-glycerol neurolytic block was performed twice at the L2/3 intervertebral space. His analgesia was greatly improved and high-dose intravenous opioid was retitrated and ceased. He remained comfortable and lucid at home for 2 months, until 2 days before his death at hospital. Intrathecal neurolytic block may be appropriate for some patients suffering from refractory pain that is resistant to conventional opioid analgesic treatment.

Review article: palliative care in gynecologic oncology

Patients with advanced gynecologic malignancies have a multitude of symptoms; pain, nausea, and vomiting, constipation, anorexia, diarrhea, dyspnea, as well as symptoms resulting from intestinal obstruction, hypercalcemia, ascites, and/or ureteral obstruction. Pain is best addressed through a multimodal approach. The optimum palliative management of end-stage malignant intestinal obstruction remains controversial, with no clear guidelines governing the choice of surgical versus medical management. Patient selection for palliative surgery, therefore, should be highly individualized because only carefully selected candidates may derive real benefit from such surgeries. There remains a real need for more emphasis on palliative care education in training programs.

Coupled obturator neurotomies and lidocaine intrathecal infusion to treat bilateral adductor spasticity and drug-refractory pain

Spastic diplegia is present in three-fourths of children with cerebral palsy, interfering with gait and frequently accompanied by severe pain. The authors report the case of a 28-year-old woman with history of perinatal hypoxia, who presented with cerebral palsy and severe spastic diplegia (Ashworth Scale Score 4, Tardieu Scale Score 5) and was confined to a wheelchair. She complained of pain in the left hip and knee with mixed neuropathic and somatic components. She consistently rated pain intensity as 10 of 10 on a visual analog scale, and her symptoms were resistant to multiple treatments. The patient underwent selective bilateral adductor myotomies and the implantation of an infusion pump for intrathecal lidocaine application. Postoperative control of pain and spasticity was dramatic (scores of 0 on the Ashworth, Tardieu, and visual analog scales) and persisted throughout a follow-up period of 36 months. This is the first report in the literature of combined selective neurotomies for the treatment of spasticity and chronic lidocaine subarachnoid infusion to treat associated pain. This therapy could represent an alternative to treat spasticity associated with neuropathic and somatic pain.

Evolution of the scientific literature on pain from 1976 to 2007

OBJECTIVE

This study traces the evolution of the scientific literature on pain published during the last 30+ years (1976-2007).

METHODS

Using the Web of Science, pain-focused journal articles from the Science Citation Index Expanded published in 1977, 1987, 1997, and 2007 were retrieved and analyzed.

RESULTS

The number of pain-related publications rose from 1,562 articles for 1976-77 to 9,159 PubMed for 2006-2007, with slow growth for the period 1976-1995, and rapid increases from 1995-2007. The analysis of contributing countries showed two major players, the United States and the UK; the doubling of the number of countries involved in pain research from 40 in 1977 to 82 in 2007; and the appearance in 2007 of The Netherlands, Turkey, China, and Brazil among the top-15 most prolific contributors. During the 30-year period, the number of journals publishing pain-related research increased nearly 2.5-fold (363 journals in 1977 vs 972 in 2007), including 14 new, international pain-focused journals since 2000. Additionally, while there were only two pain journals (Pain and Headache) in 1977, 15 pain-focused journals were indexed in 2007 with the result that 17 of the top-20 pain-focused journals in 2007 did not exist in 1977.

CONCLUSION

The rapid evolution and explosion of pain research in the last 30+ years was reflected in substantial changes in the landscape of the contributing countries and in the scientific journals targeted by pain researchers.

Transforaminal 5% phenol neurolysis for the treatment of intractable cancer pain

This is the first case report of using a transforaminal approach for phenol administration. A 76-yr-old patient with a history of leiomyosarcoma and multiple metastatic lesions had unremitting pain in the right thoracic and lumbar regions and had prohibitive opioid-induced side effects. The patient underwent phenol neurolysis using a transforaminal approach in 2 stages at 3 levels (L3-4, L1-2, and T12-L1). The patient had complete resolution of pain, without any complications, and opioid treatment was nearly discontinued. Transforaminal phenol neurolysis is a reasonable treatment option for patients suffering from intractable pain for whom conventional therapies have proven ineffective.

Intrathecal infusions for intractable cancer pain: a qualitative study of the impact on a case series of patients and caregivers

BACKGROUND

The need for intrathecal infusion in a palliative care setting is infrequent. Despite established efficacy, safety and cost effectiveness, this is considered an 'extraordinary measure' in Canada. Patients requiring this approach are not typical palliative care patients, having shorter and more uncertain life expectancies.

OBJECTIVES

The present study is a qualitative exploration of the impact of intrathecal pump implantation on cancer patients, and also the impact of the intervention on the staff caring for those patients.

METHODS

Palliative care unit patients who received an implanted intrathecal pump or dome catheter for intractable cancer pain participated in multiple semistructured interviews. Doctors and nurses caring for each patient were also interviewed. Interviews were recorded and analyzed for themes. The study terminated when saturation was reached.

RESULTS

Six patients participated, with up to three interviews each. Twenty-four staff interviews took place. Patients' hopes and expectations were not always fully met, but the infusions had a profound positive effect on quality of life. Patients expressed anxiety about dependence on the device, and also on a few highly skilled individuals. Staff interviews revealed a significant impact on the 'culture' of the palliative care unit. Clear communication of the rationale for infusion was very important, as was regular education about infusion management.

CONCLUSIONS

Implanted intrathecal infusion devices are a necessary part of a tertiary level cancer pain management service for the unfortunate minority with intractable pain. Practical recommendations for care are made for palliative care programs contemplating offering intrathecal infusions.