Pain Management in Metastatic Bone Disease: A Literature Review

Breakthrough pain and rapid-onset opioids in patients with cancer pain: a narrative review

Breakthrough pain is transitory pain that occurs despite the use of opioids for background pain control. Breakthrough pain occurs in 40% to 80% of patients with cancer pain. Despite effective analgesic therapy, patients and their caregivers often feel that their pain is not sufficiently controlled. Therefore, an improved understanding of breakthrough pain and its management is essential for all physicians caring for patients with cancer. This article reviews the definition, clinical manifestations, accurate diagnostic strategies, and optimal treatment options for breakthrough pain in patients with cancer. This review focuses on the efficacy and safety of rapid-onset opioids, which are the primary rescue drugs for breakthrough pain.

Effects of Opioids, Steroids, Benzodiazepines, Anticholinergics, and Antihistamines on the Efficacy of Antipsychotics for Treating Delirium in End-of-Life Adult Patients Undergoing Palliative Care

The purpose of the study was to determine the effect of combination therapy involving opioids, steroids, benzodiazepines, anticholinergics, and antihistamines on antipsychotics efficacy for delirium. The study included adult inpatients receiving end-of-life palliative care and diagnosed with hyperactive delirium. Changes in delirium symptoms were assessed using the Intensive Care Delirium Screening Checklist (ICDSC). A retrospective analysis was conducted on 97 patients with ICDSC scores of ≥4, comparing the scores before and after antipsychotic administration. A mean score <4 sustained for 3 days after antipsychotics administration was considered effective. The mean days with ICDSC <4 within a 3-day period were evaluated as well. The efficacy of antipsychotics was compared between cases with and without the use of opioids, steroids, benzodiazepines, anticholinergics, and antihistamines. The results revealed no significant differences in the efficacy of antipsychotics for delirium when used in conjunction with opioids (odds ratio 0.614, 95% CI [0.179-2.105]), benzodiazepines (0.387, [0.108-1.390]), steroids (1.258, [0.276-5.746]), or anticholinergics (2.085, [0. 148-29.458]). Additionally, no significant differences were observed in the mean days with ICDSC <4 within 3-day period. Although opioids, benzodiazepines, steroids, anticholinergics, and antihistamines are recognized as delirium risk factors, their use for symptom relief in patients with delirium may not affect antipsychotic efficacy.

Ion channels in cancer-induced bone pain: from molecular mechanisms to clinical applications

Cancer-induced bone pain (CIBP) caused by bone metastasis is one of the most prevalent diseases, and current treatments rely primarily on opioids, which have significant side effects. However, recent developments in pharmaceutical science have identified several new mechanisms for CIBP, including the targeted modification of certain ion channels and receptors. Ion channels are transmembrane proteins, which are situated on biological cell membranes, which facilitate passive transport of inorganic ions across membranes. They are involved in various physiological processes, including transmission of pain signals in the nervous system. In recent years, there has been an increasing interest in the role of ion channels in chronic pain, including CIBP. Therefore, in this review, we summarize the current literature on ion channels, related receptors, and drugs and explore the mechanism of CIBP. Targeting ion channels and regulating their activity might be key to treating pain associated with bone cancer and offer new treatment avenues.

The Edmonton Classification System for Cancer Pain in Patients with Bone Metastasis: a descriptive cohort study

PURPOSE

We describe the prevalence of the Edmonton Classification System for Cancer Pain (ECS-CP) features in patients with bone metastasis and cancer-induced bone pain (CIBP) and the relationship between ECS-CP features, pain intensity, and opioid consumption.

METHODS

We assessed ECS-CP features and recoded pain mechanisms and opioid use in adult patients with bone metastasis. Validated measures were used to assess pain intensity, incident pain, psychological distress, addictive behavior, and cognition.

RESULTS

Among 147 eligible patients, 95.2% completed the assessment. Mean participant age was 73.2 years, the majority female (52.1%) with breast cancer occurring most commonly (25.7%). One or more ECS-CP features were present in 96.4% and CIBP in 75.7% of patients. The median average and worst pain scores were 3 and 6, respectively. Neuropathic pain was the most prevalent pain mechanism (45.0%) and was associated with breakthrough pain frequency (p=0.014). Three-quarters had incident pain, which was strongly associated with a higher average and worst pain scores (3.5 and 7, p<0.001 for both), background oral morphine equivalent daily dose (26.7mg, p=0.005), and frequency of daily breakthrough analgesia (1.7 doses/day, p=0.007). Psychological distress (n=90, 64.3%) was associated with a significantly higher average pain score (4, p=0.009) and a slightly higher worst pain score (7, p=0.054). Addictive behaviour and cognitive dysfunction were relatively uncommon (18.6% and 12.9%, respectively).

CONCLUSION

There is a need to promote standardized assessment and classification of pain syndromes such as CIBP. The ECS-CP may allow us to consider CIBP in a systematic manner and develop personalized pain interventions appropriate to the pain profile.

TRIAL REGISTRATION

Retrospectively registered in ANZCTR ACTRN12622000853741 (16/06/2022).

Analysis of Various Factors Associated With Opioid Dose Escalation in Patients With Cancer Pain

Introduction

Pain is one of the most important symptoms in terms of prevalence and a major cause of distress in patients with cancer. Therefore, this study aimed to analyze and identify the factors that influence the worsening of pain in patients with cancer necessitating opioid dose escalation.

Methods

The study was conducted in a single center. This study is a retrospective cohort study of 390 adult cancer patients. The primary endpoint was dose escalation for strong opioids. Adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) were calculated using a logistic regression model to evaluate the relationships of factors with opioid dose escalation for cancer pain.

Results

Polypharmacy was associated with opioid dose escalation (aOR = 2.54, 95% CI = 1.486-4.370, p = 0.001). Conversely, alcohol consumption was associated with a reduced need for dose escalation (aOR = 0.60, 95% CI = 0.376-0.985, p = 0.043).

Conclusion

The results of this study indicate that moderate alcohol consumption does not reduce the efficacy of opioids in patients with cancer pain. Meanwhile, patients receiving polypharmacy may be able to more rapidly alleviate their pain via early opioid dose modification.

Spinal Cord Stimulation as Treatment for Cancer and Chemotherapy-Induced Pain

Neuropathic pain is a rampant disease exacting a significant toll on patients, providers, and health care systems around the globe. Neuromodulation has been successfully employed to treat many indications including failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), phantom limb pain (PLP), radiculopathies, and intractable pelvic pain, among many others. Recent studies have also demonstrated efficacy for cancer-related pain and chemotherapy induced neuropathy with these techniques. Spinal cord stimulation (SCS) is the most commonly employed technique and involves implantation of percutaneous or paddle leads targeting the dorsal columns of the spinal cord with the goal of disrupting the pain signals traveling to the brain. Tonic, high frequency, and burst waveforms have all been shown to reduce pain and disability in chronic pain patients. Closed-loop SCS systems that automatically adjust stimulation parameters based on feedback (such as evoked compound action potentials) are becoming increasingly used to help ease the burden placed on patients to adjust their programming to their pain and position. Additionally, dorsal root ganglion stimulation (DRGS) is a newer technique that allows for dermatomal coverage especially in patients with pain in up to two dermatomes. Regardless of the technique chosen, neuromodulation has been shown to be cost-effective and efficacious and should be given full consideration in patients with chronic pain conditions.

Targeting the Wnt signaling pathway for breast cancer bone metastasis therapy

Osteolytic bone destruction is found in approximately 60% of advanced breast cancer patients. With the pathogenesis of bone metastasis being unclear, traditional antiresorptive therapeutic strategies might not be ideal for treatment. The Wnt pathway is a highly organized cascade involved in multiple stages of cancer bone metastasis, and Wnt-targeted therapeutic strategies have shown promise in achieving favorable outcomes. In this review, we summarize the current progress of pharmacological Wnt modulators against breast cancer bone metastasis, discuss emerging therapeutic strategies based on Wnt pathway-related targets for bone therapy, and highlight opportunities to better harness the Wnt pathway for bone metastasis therapeutics to further reveal the implications of the Wnt pathway in bone metastasis pathology and provide new ideas for the development of Wnt-based intervention strategies against breast cancer bone metastasis.

Multifarious Targets and Recent Developments in the Therapeutics for the Management of Bone Cancer Pain

Bone cancer pain (BCP) is a distinct pain state showing characteristics of both neuropathic and inflammatory pain. On average, almost 46% of cancer patients exhibit BCP with numbers flaring up to as high as 76% for terminally ill patients. Patients suffering from BCP experience a compromised quality of life, and the unavailability of effective therapeutics makes this a more devastating condition. In every individual cancer patient, the pain is driven by different mechanisms at different sites. The mechanisms behind the manifestation of BCP are very complex and poorly understood, which creates a substantial barrier to drug development. Nevertheless, some of the key mechanisms involved have been identified and are being explored further to develop targeted molecules. Developing a multitarget approach might be beneficial in this case as the underlying mechanism is not fixed and usually a number of these pathways are simultaneously dysregulated. In this review, we have discussed the role of recently identified novel modulators and mechanisms involved in the development of BCP. They include ion channels and receptors involved in sensing alteration of temperature and acidic microenvironment, immune system activation, sodium channels, endothelins, protease-activated receptors, neurotrophins, motor proteins mediated trafficking of glutamate receptor, and some bone-specific mechanisms. Apart from this, we have also discussed some of the novel approaches under preclinical and clinical development for the treatment of bone cancer pain.

ACE2/Angiotensin-(1-7)/Mas Receptor Axis in Human Cancer: Potential Role for Pediatric Tumors

BACKGROUND

Pediatric tumors remain the highest cause of death in developed countries. Research on novel therapeutic strategies with lesser side effects is of utmost importance. In this scenario, the role of Renin-Angiotensin System (RAS) axes, the classical one formed by angiotensinconverting enzyme (ACE), Angiotensin II and AT1 receptor and the alternative axis composed by ACE2, Angiotensin-(1-7) and Mas receptor, have been investigated in cancer.

OBJECTIVE

This review aimed to summarize the pathophysiological role of RAS in cancer, evidence for anti-tumor effects of ACE2/Angiotensin-(1-7)/Mas receptor axis and future therapeutic perspectives for pediatric cancer.

METHODS

Pubmed, Scopus and Scielo were searched in regard to RAS molecules in human cancer and pediatric patients. The search terms were "RAS", "ACE", "Angiotensin-(1-7)", "ACE2", "Angiotensin II", "AT1 receptor", "Mas receptor", "Pediatric", "Cancer".

RESULTS

Experimental studies have shown that Angiotensin-(1-7) inhibits the growth of tumor cells and reduces local inflammation and angiogenesis in several types of cancer. Clinical trials with Angiotensin-( 1-7) or TXA127, a pharmaceutical grade formulation of the naturally occurring peptide, have reported promising findings, but not enough to recommend medical use in human cancer. In regard to pediatric cancer, only three articles that marginally investigated RAS components were found and none of them evaluated molecules of the alternative RAS axis.

CONCLUSION

Despite the potential applicability of Angiotensin-(1-7) in pediatric tumors, the role of this molecule was never tested. Further clinical trials are necessary, also including pediatric patients, to confirm safety and efficiency and to define therapeutic targets.

Phosphoproteomic Profiling of Rat's Dorsal Root Ganglia Reveals mTOR as a Potential Target in Bone Cancer Pain and Electro-Acupuncture's Analgesia

Bone cancer pain (BCP) is a clinical refractory mixed pain involving neuropathic and inflammatory pain, with the underlying mechanisms remaining largely unknown. Electro-acupuncture (EA) can partly alleviate BCP according to previous research. We aim to explore the proteins and major pathways involved in BCP and EA treatment through phosphoproteomic profiling. BCP rat model was built by tibial inoculation of MRMT-1 mammary gland carcinoma cells. Mechanical hyperalgesia determined by paw withdrawal thresholds (PWTs) and bone destruction manifested on the radiographs confirmed the success of modeling, which were attenuated by EA treatment. The differentially expressed phosphorylated proteins (DEPs) co-regulated by BCP modeling and EA treatment in rat dorsal root ganglions (DRGs) were analyzed through PEX100 Protein microarray. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that DEPs were significantly enriched in mammalian target of rapamycin (mTOR) signaling pathway. The phosphorylations of mTOR at Ser2448 and Thr2446 were increased in BCP and downregulated by EA. In addition, the phosphorylation of S6K and Akt, markers of the mTOR complex, were also increased in BCP and downregulated by EA. Inhibition of mTOR signaling alleviated the PWTs of BCP rats, while the mTOR agonist impaired the analgesic effect of EA. Thus, our study provided a landscape of protein phosphorylation changes in DRGs of EA-treated BCP rats and revealed that mTOR signaling can be potentially targeted to alleviate BCP by EA treatment.

Effectiveness of Antalgic Therapies in Patients with Vertebral Bone Metastasis: A Protocol for a Systematic Review and Meta-Analysis

There is no systematic review that has identified existing studies evaluating the pharmacological and non-pharmacological intervention for pain management in patients with bone metastasis. To fill this gap in the literature, this systematic review with meta-analysis aims to evaluate the effectiveness of different antalgic therapies (pharmacological and non-pharmacological) in the improvement of pain of these patients. To this end, this protocol has been written according to the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) and registered in PROSPERO (CRD42020135762). A systematic search will be carried out in four international databases: Medline (Via PubMed), Web of Science, Cochrane Library and SCOPUS, to select the randomized controlled clinical trials. The Risk of Bias Tool developed by Cochrane will be used to assess the risk of bias and the quality of the identified studies. A narrative synthesis will be used to describe and compare the studies, and after the data extraction, random effects model and a subgroup analyses will be performed according to the type of intervention, if possible. This protocol aims to generate a systematic review that compiles and synthesizes the best and most recent evidence on the treatment of pain derived from vertebral metastasis.

Image-guided Cryotherapy for Musculoskeletal Tumors

BACKGROUND

This article represents a review of the use of image-guided cryotherapy in the treatment of musculoskeletal tumor lesions. Cryotherapy is able to induce a lethal effect on cancer cells through direct and indirect mechanisms. In this manuscript, we combined our experience with that of other authors who have published on this topic in order to provide indications on when to use cryotherapy in musculoskeletal oncology.

DISCUSSION

Image-Guided percutaneous cryotherapy is a therapeutic method now widely accepted in the treatment of patients with musculoskeletal tumors. It can be used both for palliative treatments of metastatic bone lesions and for the curative treatment of benign bone tumors, such as osteoid osteoma or osteoblastoma. In the treatment of bone metastases, cryotherapy plays a major role in alleviating or resolving disease-related pain, but it has also been demonstrated that it can have a role in local disease control. In recent years, the use of cryotherapy has also expanded for the treatment of both benign and malignant soft tissue tumors.

CONCLUSION

Percutaneous cryotherapy can be considered a safe and effective technique in the treatment of benign and malignant musculoskeletal tumors. Cryotherapy can be considered the first option in benign tumor lesions, such as osteoid osteoma, and a valid alternative to radiofrequency ablation. In the treatment of painful bone metastases, it must be considered secondarily to other standard treatments (radiotherapy, bisphosphonate therapy, and chemotherapy) when they are no longer effective in controlling the disease or when they cannot be repeated (for example, radiotherapy).

An Overview of Decision Making in the Management of Metastatic Spinal Tumors

INTRODUCTION

Spinal metastases are the most commonly encountered spinal tumors. With increasing life expectancy and better systemic treatment options, the incidence of patients seeking treatment for spinal metastasis is rising. Radical resections and conventional low-dose radiotherapy have given way to modern 'separation' surgeries and stereotactic body radiotherapy which entails lesser morbidity and improved local control. This article provides an overview of the decision making and currently available treatment options for metastatic spinal tumors.

METHODS

A MEDLINE literature search was made for studies in English language reporting on human subjects, describing results of various treatment options that are a part of multidisciplinary management of metastatic spinal tumors. The highest-quality evidence available in the literature was reviewed.

DISCUSSION

Treatment of patients with metastatic spinal tumors is largely palliative, with radiotherapy and selective surgery being the mainstays of management. Multidisciplinary management that incorporates factors like patient performance status, expected survival and systemic burden of disease and employs well-validated decision-making frameworks for guiding treatment holds the key to an effective palliative treatment strategy. Effective pain management, achieving local control, adequate neurological decompression in the setting of epidural cord compression and surgical stabilization for mechanical stabilization are the main goals of treatment.

CONCLUSION

The management of metastatic spinal tumors has been rapidly evolving; currently, limited decompression and stabilization followed by postoperative SBRT for local tumor control are associated with less morbidity and may be referred to as the current standard of care in these patients.

Management of cancer pain with analgetic adjuvant and weak opioid in prostate cancer bone metastases: A case series

BACKGROUND

In cancer patients, cancer pain is the most common cancer complication. About 60-90% of patients with advanced stage cancer experience various levels of pain, and about 30% of patients have been suffering from persistent severe pain. Bones are the most frequent targets of metastases in patients with cancer such as breast, prostate, lung, kidney, and thyroid. In advanced prostate cancer, bone metastasis leads to bone pain, skeletal fracture, and increased mortality. At least 75% of patients with bone metastasis experience bone pain.

CASE DESCRIPTION

We report three cases of cancer pain, treated with primary cancer from the prostate metastasis to the spine. All three patients had lower back pain that radiated to the left and right limbs, with mixed pain and bone pain, where early hospital admission shows the Numeric Rating Scale (NRS) pain scale 9-10. Treated with administration of adjuvant therapy (Gabapentin) and weak opioids (injections of Tramadol) as well as injections of Metylprednisolone (for 3 days), the patient's pain scale was evaluated, and the average NRS obtained on days 2-4 was 5-6. On day 5-8, treatment continued with Gabapentin and Tramadol injections, and the pain scale (NRS) decreased to 2-3. All patients on the 8-9th day of treatment also received Biphosphonates to reduce pain, bone damage, fracture risk, and blood calcium levels. Patients can be discharged with an oral Gabapentin prescription only.

CONCLUSION

A pain scale (NRS) reduction of >50% is obtained from the initial pain scale in cancer pain patients treated using a combination of adjuvant therapy and weak opioids.

Clinical and functional comparison of dynamic hip screws and intramedullary nails for treating proximal femur metastases in older individuals

Objective

To compare the outcomes of dynamic hip screws (DHS) and intramedullary nailing (IMN) in the treatment of extra-capsular metastatic carcinoma of the proximal femur.

Methods

A retrospective case analysis method was used to examine data of patients with proximal metastatic cancer of the femur who were treated with internal fixation in Department of Orthopaedics, Beijing Friendship Hospital, from January 2007 to December 2018. Blood loss, postoperative pain, functional score, length of stay, and survival rates were compared, and postoperative complications were assessed.

Results

Complete follow-up data were available for 33 patients. The mean follow-up period was 12.2±3.6 (range: 9−32) months and the average age was 72.3±4.7 (range: 59−83) years old. There were 20 females and 13 males. Twenty-three patients had undergone IMN and 10 DHS, according to bone defects and the patient’s overall condition. The median survival time was 10 months in the IMN group and 11 months in the DHS group. Duration of surgery (t=−7.366, P<0.001) and length of hospital stay (t=−3.509, P<0.001) differed significantly between the two groups. There was one case of breakage of internal fixation in the IMN group.

Conclusions

There was no significant difference between DHS and IMN in terms of surgical efficacy. IMN and DHS were different in terms of surgical time and hospital stay. However, due to the limited number of cases in this study, multi-factor analysis has not been performed and needs to be further verified in future analysis. When developing a surgical plan, it is recommended to consider the patient’s condition and the surgeon’s experience.

Topical Ketamine with Other Adjuvants: Underutilized for Refractory Cancer Pain? A Case Series and Suggested Revision of the World Health Organization Stepladder for Cancer Pain

Background: Uncontrolled cancer pain is a significant problem in palliative medicine. Opioids are often first-line treatment that increase risks of analgesic tolerance and hyperalgesia. Topical ketamine with other adjuvant pain medications is an often-overlooked treatment, yet may be most effective in difficult-to-treat cancer pain.

Objective: We report a case series of hospice patients with uncontrolled cancer pain who were suboptimally treated with opioids and nerve blocks, whose symptoms responded to topical ketamine with other adjuvants. We review the pronociceptive properties of opioids and how topical multimodal treatment of cancer pain can be more effective than standard opioids, other topical adjuvant medications, and nerve blocks. We discuss the shortcomings of the World Health Organization (WHO) stepladder for the treatment of cancer pain and suggest an adjuvant treatment algorithm, directing physicians to appropriate adjuvant pain agents based on pain type and distinct receptor actions.

Design: This is a retrospective case series of patients who responded to topical multimodal pain treatment with implementation of findings into an addendum to the WHO stepladder.

Subjects: Subjects were from a case series of community-based hospice patients with previously uncontrolled cancer pain.

Measurement: Measurement was made by self-report of pain levels using the 10-point numeric pain rating scale.

Results: Patients' pain was controlled with topical adjuvant medications with return to previously lost function and prevention of otherwise escalating opioid dosing.

Conclusions: These patient cases reveal how ketamine-based topical treatment for cancer pain can be more effective than standard opioids, other topical adjuvant medications, and nerve blocks with no noted side effects and observed reduction in opioid consumption.

Bone Metastasis Pain, from the Bench to the Bedside

Bone is the most frequent site of metastasis of the most common cancers in men and women. Bone metastasis incidence has been steadily increasing over the years, mainly because of higher life expectancy in oncologic patients. Although bone metastases are sometimes asymptomatic, their consequences are most often devastating, impairing both life quality and expectancy, due to the occurrence of the skeletal-related events, including bone fractures, hypercalcemia and spinal cord compression. Up to 75% of patients endure crippling cancer-induced bone pain (CIBP), against which we have very few weapons. This review's purpose is to discuss the molecular and cellular mechanisms that lead to CIBP, including how cancer cells convert the bone "virtuous cycle" into a cancer-fuelling "vicious cycle", and how this leads to the release of molecular mediators of pain, including protons, neurotrophins, interleukins, chemokines and ATP. Preclinical tests and assays to evaluate CIBP, including the incapacitance tester (in vivo), and neuron/glial activation in the dorsal root ganglia/spinal cord (ex vivo) will also be presented. Furthermore, current therapeutic options for CIBP are quite limited and nonspecific and they will also be discussed, along with up-and-coming options that may render CIBP easier to treat and let patients forget they are patients.

The Role of Angiotensin–(1-7) in Cancer

The rationale to investigate the role of angiotensin-(1-7) [Ang-(1-7)] in cancer relies on the fact that the heptapeptide inhibits the growth of several cell lines. The first studies showed that Ang-(1-7) accelerated hematopoietic recovery in the peripheral blood and bone marrow after chemotherapy and inhibits lung cancer cell growth through the activation of Mas receptor. In this chapter, we summarize studies on the role of Ang-(1-7) in different types of cancer, especially lung, breast, prostate, hepatocellular cancers and in gliobalstoma multiforme (GBM). The antitumor effect of Ang-(1-7) was due to reduction of angiogenesis, cancer-associated fibrosis, osteoclastogenesis, tumor-induced inflammation, and metastasis as well as inhibition of cancer cell growth and proliferation. In clinical trials, Ang-(1-7) was well tolerated with limited toxic or quality-of-life side effects and showed clinical benefit in cancer patients with solid tumors. Further clinical trials are needed to confirm safety, to determine doses and clinical indications.

Principles of Management of Extremity Skeletal Metastasis

Understanding the epidemiology of extremity skeletal metastasis and the factors deciding the treatment decision-making are essential in developing a diagnostic and treatment strategy. This leads to optimum care and reduces disease-related burden. With the evolution of medical, radiation therapy, and surgical methods, cancer care has improved the quality of life for patients with improved survival and functional status in patients with skeletal metastasis. Based on the currently available literature, we have described a step-wise evaluation and management strategy of metastatic extremity bone disease. The present review article addresses various aspects and related controversies related to evaluation, staging, and treatment options in the management of extremity bone metastasis. This article also highlights the role of multidisciplinary involvement in management of extremity skeletal metastasis.