μ-Opioid receptor gene A118G polymorphism predicts survival in patients with breast cancer

Genetic Variation A118G in the OPRM1 Gene Underlies the Dimorphic Response to Epidural Opioid-Induced Itch

Neuraxial opioids, widely used in obstetric and perioperative pain management, often lead to unwanted itch, reducing patient satisfaction. While the μ-opioid receptor has been implicated in opioid-induced itch, the genetic basis for variable itch incidence remains unknown. This study examined 3616 patients receiving epidural opioids, revealing an itch occurrence of 26.55%, with variations among opioid types and gender. Analysis of the OPRM1 gene identified six single-nucleotide polymorphisms, notably rs1799971 (A118G), that correlated with opioid-induced itch. Mouse models with an equivalent A112G mutation showed reduced neuraxial opioid-induced itch and light touch-evoked itch, mirroring human findings. The 118G allele demonstrated an anti-itch effect without impacting analgesia, addiction, or tolerance, offering insights for risk stratification and potential anti-itch pretreatment strategies.

Potential influence of different peri-operative analgesic regimens on tumour biology and outcome after oncologic surgery: A narrative review

The management of peri-operative pain is one of the pillars of anaesthesia and is of particular importance in patients undergoing surgery for solid malignant tumours. Amongst several options, the most commonly employed analgesic regimens involve opioids, NSAIDs and regional anaesthesia techniques with different local anaesthetics. In recent years, several research reports have tried to establish a connection between peri-operative anaesthesia care and outcome after cancer surgery. Experimental studies have indicated that certain pain management substances may influence cancer progression, mainly by modifying the tumour's response to surgical stress and peri-operative inflammation. However, these promising in-vitro and in-vivo data have yet to be confirmed by randomised clinical trials. The reason for this might lie with the nature of tumour biology itself, and in the diversity of patient and tumour phenotypes. In a translational approach, future research should therefore concentrate on patient and tumour-related factors or biomarkers, which might either influence the tumour and its microenvironment or predict potential responses to interventions, including the choice of the analgesic. This might not only be relevant for the daily practice of clinical anaesthesia, but would also be of great importance for patients undergoing cancer surgery, who might be able to receive an individualised anaesthetic regimen based on their phenotypic profile.

Benefits of Remote-Based Mindfulness on Physical Symptom Outcomes in Cancer Survivors: Systematic Review and Meta-Analysis

Background

Many cancer survivors experience a wide range of symptoms closely linked to psychological problems, highlighting the need for psychological treatment, one of the most popular being mindfulness. The use of the internet has greatly increased in the last decade, and has encouraged the use of remote-based interventions to help people living with cancer access treatment remotely via devices.

Objective

The primary aim of this study was to explore the efficacy of internet-based mindfulness interventions on the physical symptoms of people living with cancer, where physical symptoms are defined as distressing somatic experiences (eg fatigue, insomnia, and pain) regardless of the underlying cause. The secondary aim was to investigate interventions for the quality of life (QoL).

Methods

This study followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Relevant articles were systematically searched using electronic databases, namely Scopus, Medline through PubMed, Cumulated Index in Nursing and Allied Health Literature (CINAHL) through EBSCOhost, and Cochrane Central Database. Randomized controlled and pilot trials involving adults and/or older adults with cancer and using remote-based mindfulness interventions compared to usual care were included. The quality of the trials included in this study was assessed using the revised Cochrane risk of bias, version 2.0. This study estimated the standardized mean difference (SMD) and mean difference (MD) with 95% CI. The I2 test was used to identify potential causes of heterogeneity. Publication bias was assessed using contour-enhanced funnel plots and the Egger linear regression test to reveal a small study effect.

Results

The initial search yielded 1985 records, of which 13 studies were ultimately included. After treatment, remote-based mindfulness significantly reduced fatigue (SMD -0.94; 95% CI: -1.56 to -0.33; P=.002), sleep disturbance (SMD -0.36; 95% CI: -0.60 to -0.12; P=.004), and improved physical function (SMD .25; 95% CI: 0.09 to 0.41; P=.002) compared to that observed before treatment. However, compared with usual care, remote-based mindfulness showed a statistically significant reduction only in sleep disturbance (SMD: -0.37; 95% CI: -0.58 to -0.16; P=.0006) after treatment. Moreover, remote-based mindfulness was not statistically significant in reducing pain both within and between groups.

Conclusions

Remote-based mindfulness shows promise in reducing sleep disturbances; however, its impact on fatigue, pain, and physical function may be limited.

Effects of opioid drugs on immune function in cancer patients

Opioid receptor agonists are often used when cancer patients undergo surgery or analgesic treatment. As analgesics in clinical care, opioids can provide intraoperative or to chronic cancer pain relief. Immune function plays an important role in anti-cancer therapy, with cellular immunity, comprised principally of T-lymphocytes and natural killer cells, representing the primary anti-cancer immune response. However, it remains unclear whether immune function is further affected with the use of opioids in already immunocompromised cancer patients. This article provides a review of the effects of commonly used clinical opioids, including morphine, oxycodone, fentanyl and tramadol, on immune function in cancer patients. It provides a summary of current evidence regarding the immunomodulatory effects of opioids in the cancer setting and mechanisms underlying these interactions.

Anesthesia and cancer recurrence: a narrative review

Cancer is a leading cause of death worldwide. With the increasingly aging population, the number of emerging cancer cases is expected to increase markedly in the foreseeable future. Surgical resection with adjuvant therapy is the best available option for the potential cure of many solid tumors; thus, approximately 80% of patients with cancer undergo at least one surgical procedure during their disease. Agents used in general anesthesia can modulate cytokine release, transcription factors, and/or oncogenes. This can affect host immunity and the capability of cancer cells to survive and migrate, not only during surgery but for up to several weeks after surgery. However, it remains unknown whether exposure to anesthetic agents affects cancer recurrence or metastasis. This review explores the current literature to explain whether and how the choice of anesthetic and perioperative medication affect cancer surgery outcomes.

Role of Endorphins in Breast Cancer Pathogenesis and Recovery

Understanding the relationship between stress and breast cancer development is essential to preventing and alleviating the cancer. Recent research has shed light on the cognitive, physiological, cellular, and molecular underpinnings of how the endorphin pathway and stress pathway affect breast cancer. This chapter consists of two parts. Part 1 will discuss the role of endorphins in breast cancer development. This includes a discussion of three topics: (1) the neurophysiological effect of endorphins on breast tumor growth in vivo, along with further experiments that will deepen our knowledge of how β-endorphin affects breast cancer; (2) how both the opioid receptor and somatostatin receptor classes alter intracellular signaling in breast cancer cells; and (3) genetic alleles in the opioid signaling pathway that are correlated with increased breast cancer risk. Part 2 will discuss the role of endorphins in recovery from breast cancer. This includes a discussion of three topics: (1) the relationship between breast cancer diagnosis and depression; (2) the effectiveness of cognitive behavioral therapy in reducing stress in breast cancer patients; and (3) the effect of psychotherapy and exercise on preserving telomere length in breast cancer patients.

Involvement of the Opioid Peptide Family in Cancer Progression

Peptides mediate cancer progression favoring the mitogenesis, migration, and invasion of tumor cells, promoting metastasis and anti-apoptotic mechanisms, and facilitating angiogenesis/lymphangiogenesis. Tumor cells overexpress peptide receptors, crucial targets for developing specific treatments against cancer cells using peptide receptor antagonists and promoting apoptosis in tumor cells. Opioids exert an antitumoral effect, whereas others promote tumor growth and metastasis. This review updates the findings regarding the involvement of opioid peptides (enkephalins, endorphins, and dynorphins) in cancer development. Anticancer therapeutic strategies targeting the opioid peptidergic system and the main research lines to be developed regarding the topic reviewed are suggested. There is much to investigate about opioid peptides and cancer: basic information is scarce, incomplete, or absent in many tumors. This knowledge is crucial since promising anticancer strategies could be developed alone or in combination therapies with chemotherapy/radiotherapy.

Mapping the Evidence for Opioid-Mediated Changes in Malignancy and Chemotherapeutic Efficacy: Protocol for a Scoping Review

BACKGROUND

Numerous reports contend opioids can augment or inhibit malignancy. At present, there is no consensus on the risk or benefit posed by opioids on malignancy or chemotherapeutic activity. Distinguishing the consequences of opioid use from pain and its management is challenging. Additionally, opioid concentration data is often lacking in clinical studies. A scoping review approach inclusive of preclinical and clinical data will improve our understanding of the risk-benefit relationship concerning commonly prescribed opioids and cancer and cancer treatment.

OBJECTIVE

The aim of the study is to map diverse studies spanning from preclinical to clinical regarding opioids with malignancy and its treatment.

METHODS

This scoping review will use the Arksey six stages framework to (1) identify the research question; (2) identify relevant studies; (3) select studies meeting criteria; (4) extract and chart data; (5) collate, summarize, and report results; and (6) conduct expert consultation. An initial pilot study was undertaken to (1) parameterize the extent and scale of existing data for an evidence review, (2) identify key factors to be extracted in systematic charting efforts, and (3) assess opioid concentration as a variable for its relevance to the central hypothesis. Six databases will be searched with no filters: MEDLINE, Embase, CINAHL Complete, Cochrane Library, Biological Sciences Collection, and International Pharmaceutical Abstracts. Trial registries will include ClinicalTrials.gov, Cochrane CENTRAL, International Standard Randomised Controlled Trial Number Registry, European Union Clinical Trials Register, and World Health Organization International Clinical Trials Registry. Eligibility criteria will include preclinical and clinical study data on opioids effects on tumor growth or survival, or alteration on the antineoplastic activity of chemotherapeutics. We will chart data on (1) opioid concentration from human subjects with cancer, yielding a "physiologic range" to better interpret available preclinical data; (2) patterns of opioid exposure with disease and treatment-related patient outcomes; and (3) the influence of opioids on cancer cell survival, as well as opioid-related changes to cancer cell susceptibility for chemotherapeutics.

RESULTS

This scoping review will present results in narrative forms as well as with the use of tables and diagrams. Initiated in February 2021 at the University of Utah, this protocol is anticipated to generate a scoping review by August 2023. The results of the scoping review will be disseminated through scientific conference proceedings and presentations, stakeholder meetings, and by publication in a peer-reviewed journal.

CONCLUSIONS

The findings of this scoping review will provide a comprehensive description of the consequences of prescription opioids on malignancy and its treatment. By incorporating preclinical and clinical data, this scoping review will invite novel comparisons across study types that could inform new basic, translational, and clinical studies regarding risks and benefits of opioid use among patients with cancer.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/38167.

Combined Ultrasound-Guided Thoracic Paravertebral Nerve Block with Subcostal Transversus Abdominis Plane Block for Analgesia After Total Minimally Invasive Mckeown Esophagectomy: A Randomized, Controlled, and Prospective Study

INTRODUCTION

Thoracic paravertebral block (TPVB) and subcostal transverse abdominis plane block (TAP) have been considered to provide an effective analgesic effect for laparoscopic and thoracoscopic surgery, respectively. The purpose of this randomized, controlled, and prospective study was to evaluate the analgesic effect of TPVB combined with TAP in patients undergoing total minimally invasive Mckeown esophagectomy.

METHODS

Between February 2020 and December 2021, a total of 168 esophageal cancer patients undergoing McKeown esophagectomy at the Cancer Center of Sun Yat-Sen University, China, were randomly assigned to receive patient-controlled epidural analgesia alone (group PCEA, n = 56), patient-controlled intravenous analgesia alone (group PCIA, n = 56), and TPVB combined with TAP and patient-controlled intravenous analgesia (group PVB, n = 56). The primary outcome was a visual analogue scale (VAS) pain score on movement 48 h postoperatively. Secondary endpoints were pain scores at other points, intervention-related side effects, surgical complications, and length of intensive care unit and hospital stay. For the VAS pain score, the Kruskal-Wallis method was conducted for comparison of 3 treatment groups and further pairwise comparison with Bonferroni correction.

RESULTS

On movement, the VAS in the PVB group was higher than that in the PCEA group at 48 h, 72 h, 96 h, and 120 h postoperatively (p < 0.05) except in the postoperative anesthesia care unit (PACU) and 24 h postoperatively. The VAS in the PCIA group was higher than the PCEA and PVB groups in the first 4 days after surgery. The pulmonary complication rate in the PCIA group was significantly higher than the rate in the PCEA [95% Confidence Interval 0.214 (0.354, 0.067), p = 0.024].

CONCLUSIONS

Combined TPVB and TAP was more effective than intravenous opioid analgesia alone, while PCEA was more effective than TPVB combined with TAP and intravenous opioid analgesia for patients after McKeown esophagectomy.

TRIAL REGISTRATION

Chinese Clinical Trial Registry; ChiCTR2000029588.

Research in Perioperative Care of the Cancer Patient: Opportunities and Challenges

The theory that the perioperative period is critical for oncological outcomes has been a matter of extensive preclinical and clinical research. Basic science research strongly supports the notion that surgical stress, anesthetics, and analgesics influence the mechanisms of cancer progression. Hence, it is hypothesized that perioperative interventions that impact mechanisms or predictors of tumor progression can also affect patients' survival. As a result of that hypothesis, clinical researchers have conducted many retrospective studies. However, much fewer randomized controlled trials have been performed to investigate whether surgery itself (minimally invasive versus open procedures), anesthetics (volatile anesthetics versus propofol-based anesthesia), analgesics (opioids versus opioid-free anesthesia), and blood transfusions (transfusions versus no transfusions) modify the survival of patients with cancer. Unfortunately, randomized controlled trials have failed to translate the preclinical results into clinical outcomes. In this review, I will highlight the challenges of translating basic science to clinical outcomes. We will also point out opportunities for future research.

Patient Comfort During Postop Period in Breast Cancer Surgeries: A Randomized Controlled Trial Comparing Opioid and Opioid-Free Anesthesia

BACKGROUND

Anesthetic management practices have advanced to opioid-free anesthesia (OFA) often replacing opioids in oncologic surgeries. The study was conducted to find the quality of recovery (QoR) of patients undergoing breast cancer surgeries receiving OFA.

METHODS

A double-blinded, randomized controlled study was conducted with 60 patients randomized to group OFA and group OA (opioid anesthesia). Group OFA received one-time dosing of ketamine 0.3 mg/kg, lignocaine 1.5 mg/kg, and dexmedetomidine 1 mcg/kg. Group OA received fentanyl 2mcg/kg. Intraoperatively, Group OFA received dexmedetomidine 0.4 mcg/kg/h and the OA group received fentanyl 0.5 mcg/kg/h infusion. Bispectral index (BIS), hemodynamics, muscle relaxant administration, and sevoflurane concentration were noted. A modified QoR-40 score was used to assess the quality of recovery in the postoperative period.

RESULTS

A higher QoR-40 score was found in the OA group (median 182, IQR 178-186) compared to the OFA group (median 180, IQR 178-184). Out of the five components, the patient's emotional state was better in the group OA (39.9±2.77) than in the OFA group (37.9±2.77). The patient's physical comfort was found to be better in the group OFA (52.52±3.23) compared to group OA (50.93±3.23). Physical independence, psychological support, and pain were comparable between the two groups. Patients in group OFA received less sevoflurane, a muscle relaxant, and showed a mild reduction in heart rate and mean arterial pressure (MAP) when compared to group OA. The time taken to reach a Modified Aldrete score of 9 was high in OFA (11.47±2.16) and (9.17±1.09) when compared to group OA. No significant differences were noted with the visual analog score (VAS) score, Ramsay sedation score, and modified post-anesthesia discharge scoring system (PADSS) score.

CONCLUSION

We conclude that the quality of recovery of patients receiving opioid-free methods of anesthesia was not inferior to OA in patients undergoing breast cancer surgeries.

Effect of Opioids on Survival in Patients with Cancer

Opioids are commonly used for pain management in patients with cancer. They have a range of unwanted effects, including some that potentially influence cancer growth. This article reviews the data assessing the effects of opioids on survival in patients with cancer. Many studies assessing this show an association between opioids and decreased survival. This effect is present even at very low doses of opioids. These studies do not assess causality, so it is not known if it is a direct effect of opioids on survival. As the control groups are not matched to the opioid group it might be that opioids are being used to control pain and patients receiving opioids have more aggressive cancers and it is the underlying cancer which is causing the decreased survival. Furthermore, although some studies allude to different opioids having different effects on survival, often all opioids are pooled in analysis. Future work needs to try to ascertain causality and differentiate between different opioids, pain, and cancer-mediated effects on survival in specific cancer types. Until then, opioids should continue to be used in patients with cancer as part of measures to optimise comfort and quality of life.

Less Well-Known Consequences of the Long-Term Use of Opioid Analgesics: A Comprehensive Literature Review

BACKGROUND

The adverse effects of short-term opioid analgesics are well known and acknowledged; however, the spectrum of the sequelae of long-term use seems less clear. Some effects may remain undetected but still have the potential to cause harm and reduce patients' quality of life.

OBJECTIVE

To review the literature on the adverse effects of long-term opioid therapy.

METHODS

We performed a quasi-systematic search, analyzing articles published in the MEDLINE database between January 2000 and March 2021 that identified adverse effects of opioids used for chronic pain treatment.

RESULTS

Growing evidence indicates that there are multiple serious adverse effects of opioid treatment. Long-term opioid use may have significant effects on the endocrine, immune, cardiovascular, respiratory, gastrointestinal, and neural systems. Studies show that long-term opioid treatment increases the risk of fractures, infections, cardiovascular complications, sleep-disordered breathing, bowel dysfunction, overdose, and mortality. Opioids may potentially affect cancer development. Most consequences of the long-term use of opioids have been identified in studies of patients with non-malignant pain.

CONCLUSION

Studies indicate that long-term use of opioids increases the risk of drug-related events in a significant number of patients. Clinicians should be aware of these complications associated with prescribing opioids, discuss them with patients, prevent complications, if possible, and diagnose them early and manage adequately. More human studies are needed to assess the risk, including trials with individual opioids, because they have different adverse effect profiles.

Solid Tumor Opioid Receptor Expression and Oncologic Outcomes: Analysis of the Cancer Genome Atlas and Genotype Tissue Expression Project

Background

Opioid receptors are expressed not only by neural cells in the central nervous system, but also by many solid tumor cancer cells. Whether perioperative opioids given for analgesia after tumor resection surgery might inadvertently activate tumor cells, promoting recurrence or metastasis, remains controversial. We analysed large public gene repositories of solid tumors to investigate differences in opioid receptor expression between normal and tumor tissues and their association with long-term oncologic outcomes.

Methods

We investigated the normalized gene expression of µ, κ, δ opioid receptors (MOR, KOR, DOR), Opioid Growth Factor (OGFR), and Toll-Like 4 (TLR4) receptors in normal and tumor samples from twelve solid tumor types. We carried out mixed multivariable logistic and Cox regression analysis on whether there was an association between these receptors' gene expression and the tissue where found, i.e., tumor or normal tissue. We also evaluated the association between tumor opioid receptor gene expression and patient disease-free interval (DFI) and overall survival (OS).

Results

We retrieved 8,780 tissue samples, 5,852 from tumor and 2,928 from normal tissue, of which 2,252 were from the Genotype Tissue Expression Project (GTEx) and 672 from the Cancer Genome Atlas (TCGA) repository. The Odds Ratio (OR) [95%CI] for gene expression of the specific opioid receptors in the examined tumors varied: MOR: 0.74 [0.63-0.87], KOR: 1.27 [1.17-1.37], DOR: 1.66 [1.48-1.87], TLR4: 0.29 [0.26-0.32], OGFR: 2.39 [2.05-2.78]. After controlling all confounding variables, including age and cancer stage, there was no association between tumor opioid receptor expression and long-term oncologic outcomes.

Conclusion

Opioid receptor gene expression varies between different solid tumor types. There was no association between tumor opioid receptor expression and recurrence. Understanding the significance of opioid receptor expression on tumor cells remains elusive.

D,L-Methadone enhances the cytotoxic activity of standard chemotherapeutic agents on pediatric rhabdomyosarcoma

Purpose

In advanced tumor stages, pediatric rhabdomyosarcoma (RMS) shows an intrinsic resistance to standard chemotherapy, which is associated with a dismal prognosis. Alternative therapeutic approaches and optimization of already existent treatment protocols are urgently needed in these conditions. The µ-opioid receptor (OPRM1) agonist, D,L-methadone is frequently used for analgesia in oncological patients. Recent evidence has shown that D,L-methadone in combination with chemotherapeutic agents may enhance their cytotoxic effect against cancer cells. There are no related data in pediatric rhabdomyosarcoma (RMS).

Methods

Antitumor effects of combined D,L-methadone and doxorubicin, carboplatin, and vincristine on RMS cell lines RD and RH30 were analyzed using following outcome data: expression of the OPRM1 receptor (Western blot), cell growth inhibition (MTT assay), cell migration (wound-healing assay), apoptosis induction (caspase-3/7 assay), and reactive oxygen species (ROS) production (flow cytometry).

Results

In both cell lines, OPRM1 expression was significantly increased after combined treatment of D,L-methadone with all three cytotoxic drugs tested, which resulted in suppression of tumor cell growth and increase of apoptosis rates. These effects were mediated by increased ROS production and up-regulation of caspase-3/7 activity. Doxorubicin combined with D,L-methadone significantly reduced cell migration in both cell lines. Carboplatin or vincristine in combination with D,L-methadone had only an impact on cell migration in RH30 cells.

Conclusions

This new therapeutic approach in RMS provides strong antitumor effects in vitro. The combination of standard chemotherapy and D,L-methadone requires further investigation. Especially advanced tumors with a limited effectiveness of conventional treatment regimens seem a potential target of this approach.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-022-03945-y.

Genetic Polymorphisms as Predictors of Survival in Breast Cancer: Future Lessons in Historical Data

Introduction

Breast cancer is the most common cancer among women worldwide and one of the main causes of death in the female sex. Genetic polymorphisms in the mu-opioid receptor (OPRM1) and catechol-o-methyltransferase (COMT) genes have been shown to increase breast cancer risk. Variants in these genes may carry a prognostic impact in breast cancer. Long follow-up intervals are critical to adequately analyze prognosis in diseases with prolonged survival times and late relapses.

Objective

To analyze the impact of genetic polymorphisms on the survival of a cohort of breast cancer patients with very long follow-up.

Methods

This was a retrospective study of patients treated at Portuguese Oncology Institute of Porto (IPO Porto), a Portuguese comprehensive cancer center, with invasive carcinoma of the breast with very long follow-up, with analysis of genetic polymorphisms OPMR1 rs1799971 (AA vs. G allele) and COMT rs4680 (CC vs T allele) on biological samples. Statistical analysis of survival was performed using the Kaplan-Meier method, log-rank test, and Cox regression method.

Results

A total of 143 patients with invasive breast cancer were included, with a median follow-up of 21.5 years. There was a statistically significant difference in overall survival (OS) at 30 years according to the OPMR1 polymorphism, with lower survival in patients with the AA genotype (p<0.05). The difference in OS according to the COMT polymorphism was also statistically significant, with worse survival in patients with genotype T allele (p<0.05). The genetic variants were not associated with patient age, stage at diagnosis, or tumor grade.

Discussion

The genetic polymorphisms of OPRM1 and COMT affected the overall survival of breast cancer patients, in concordance with previous research. Further investigation is needed in order to clarify the prognostic impact of these genetic alterations on breast cancer.

Opioid Receptor-Mediated and Non-Opioid Receptor-Mediated Roles of Opioids in Tumour Growth and Metastasis

Opioids are administered to cancer patients in the period surrounding tumour excision, and in the management of cancer-associated pain. The effects of opioids on tumour growth and metastasis, and their consequences on disease outcome, continue to be the object of polarised, discrepant literature. It is becoming clear that opioids contribute a range of direct and indirect effects to the biology of solid tumours, to the anticancer immune response, inflammation, angiogenesis and importantly, to the tumour-promoting effects of pain. A common misconception in the literature is that the effect of opioid agonists equates the effect of the mu-opioid receptor, the major target of the analgesic effect of this class of drugs. We review the evidence on opioid receptor expression in cancer, opioid receptor polymorphisms and cancer outcome, the effect of opioid antagonists, especially the peripheral antagonist methylnaltrexone, and lastly, the evidence available of a role for opioids through non-opioid receptor mediated actions.

Can Acute Postoperative Pain Management After Tumour Resection Surgery Modulate Risk of Later Recurrence or Metastasis?

Background

Cancer is a leading cause of mortality worldwide, but death is rarely from the primary tumour: Rather it is multi-organ dysfunction from metastatic disease that is responsible for up to 90% of cancer-related deaths. Surgical resection of the primary tumour is indicated in 70% of cases. The perioperative stress response, tissue hypoxia at the site of surgery, and acute pain contribute to immunosuppression and neo-angiogenesis, potentially promoting tumour survival, proliferation, and metastasis. Poorly controlled acute postoperative pain decreases Natural Killer (NK) immune cell activity, which could potentially facilitate circulating tumour cells from evading immune detection. This consequently promotes tumour growth and distal metastasis.

Methods

We conducted a comprehensive literature search for links between acute pain and cancer outcomes using multiple online databases. Relevant articles from January 1st, 2010 to September 1st, 2021 were analysed and appraised on whether postoperative pain control can modulate the risk of recurrence, metastasis, and overall cancer survival.

Results

Although experimental and retrospective clinical data suggest a plausible role for regional anaesthesia in cancer outcome modulation, this has not been supported by the single, largest prospective trial to date concerning breast cancer. While there are mixed results on anaesthesiology drug-related interventions, the most plausible data relates to total intravenous anaesthesia with propofol, and to systemic administration of lidocaine.

Conclusion

The hypothesis that anaesthetic and analgesic technique during cancer surgery could influence risk of subsequent recurrence or metastasis has been prevalent for >15 years. The first, large-scale definitive trial among women with breast cancer found robust equivalent findings between volatile anaesthesia with opioid analgesia and regional anaesthesia. Therefore, while regional anaesthesia during tumour resection does not seem to have any effect on cancer outcomes, it remains plausible that other anaesthetic techniques (e.g. total intravenous anaesthesia and systemic lidocaine infusion) might influence oncologic outcome in other major tumour resection surgery (e.g. colorectal and lung). Therefore, another large trial is needed to definitively answer these specific research questions. Until such evidence is available, perioperative analgesia for cancer surgery of curative intent should be based on patient co-morbidity and non-cancer endpoints, such as optimising analgesia and minimising postoperative complications.

The influence of brain metastases on the central nervous system effects of methylnaltrexone: a post hoc analysis of 3 randomized, double-blind studies

PURPOSE

Peripherally acting μ-opioid receptor antagonists such as methylnaltrexone (MNTX, Relistor®) are indicated for the treatment of opioid-induced constipation (OIC). The structural properties unique to MNTX restrict it from traversing the blood-brain barrier (BBB); however, the BBB may become more permeable in patients with brain metastases. We investigated whether the presence of brain metastases in cancer patients compromises the central effects of opioids among patients receiving MNTX for OIC.

METHODS

This post hoc analysis of pooled data from 3 randomized, placebo-controlled trials included cancer patients with OIC who received MNTX or placebo. Endpoints included changes from baseline in pain scores, rescue-free laxation (RFL) within 4 or 24 h of the first dose, and treatment-emergent adverse events (TEAEs), including those potentially related to opioid withdrawal symptoms.

RESULTS

Among 356 cancer patients in the pooled population, 47 (MNTX n = 27; placebo n = 20) had brain metastases and 309 (MNTX n = 172; placebo n = 137) did not have brain metastases. No significant differences in current pain, worst pain, or change in pain scores from baseline were observed between patients treated with MNTX or placebo. Among patients with brain metastases, a significantly greater proportion of patients who received MNTX versus placebo achieved an RFL within 4 h after the first dose (70.4% vs 15.0%, respectively, p = 0.0002). TEAEs were similar between treatment groups and were generally gastrointestinal in nature and not related to opioid withdrawal.

CONCLUSION

Focal disruptions of the BBB caused by brain metastases did not appear to alter central nervous system penetrance of MNTX.

Targeting the mu-Opioid Receptor for Cancer Treatment

PURPOSE OF REVIEW

Opioids are still the most effective and widely used treatments for acute and chronic pain in cancer patients. This review focuses on the impact of opioids and mu-opioid receptors (MOR) on tumor progression and providing new ideas for targeting the MOR in cancer treatment.

RECENT FINDINGS

Studies estimated that opioids facilitate tumor progression and are related to the worse prognosis in cancer patients. As the primary receptor of opioids, MOR is involved in the regulation of malignant transformation of tumors and participating in proliferation, invasion, metastasis, and angiogenesis. MOR may be a new molecular marker of malignant tumors and thus become a new target for cancer therapy, which may be beneficial to the outcomes of cancer patients.

Intraoperative opioid exposure, tumour genomic alterations, and survival differences in people with lung adenocarcinoma

BACKGROUND

Opioids have been linked to worse oncologic outcomes in surgical patients. Studies in certain cancer types have identified associations between survival and intra-tumoural opioid receptor gene alterations, but no study has investigated whether the tumour genome interacts with opioid exposure to affect survival. We sought to determine whether intraoperative opioid exposure is associated with recurrence-specific survival and overall survival in early-stage lung adenocarcinoma, and whether selected tumour genomics are associated with this relationship. Associations between ketamine and dexmedetomidine and outcomes were also studied.

METHODS

Surgical patients (N=740) with pathological stage I-III lung adenocarcinoma and next-generation sequencing data were retrospectively reviewed from a prospectively maintained database.

RESULTS

On multivariable analysis, ketamine administration was protective for recurrence-specific survival (hazard ratio = 0.44, 95% confidence interval 0.24-0.80; P=0.007), compared with no adjunct. Higher intraoperative oral morphine milligram equivalents were significantly associated with worse overall survival (hazard ratio=1.09/10 morphine milligram equivalents, 95% confidence interval 1.02-1.17; P=0.010). Significant interaction effects were found between morphine milligram equivalents and fraction genome altered and morphine milligram equivalents and CDKN2A, such that higher fraction genome altered or CDKN2A alterations were associated with worse overall survival at higher morphine milligram equivalents (P=0.044 and P=0.052, respectively). In contrast, alterations in the Wnt (P=0.029) and Hippo (P=0.040) oncogenic pathways were associated with improved recurrence-specific survival at higher morphine milligram equivalents, compared with unaltered pathways.

CONCLUSIONS

Intraoperative opioid exposure is associated with worse overall survival, whereas ketamine exposure is associated with improved recurrence-specific survival in patients with early-stage lung adenocarcinoma. This is the first study to investigate tumour-specific genomic interactions with intraoperative opioid administration to modify survival associations.

Inhibition of mu-opioid receptor suppresses proliferation of hepatocellular carcinoma cells via CD147-p53-MAPK cascade signaling pathway

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths. Previous studies have suggested that mu-opioid receptor (MOR), a member of the opioid receptor family, is involved in the pathogenesis of HCC. However, the mechanism by which MOR regulates the biological behavior of HCC is still poorly understood. To address this problem, in this study, we investigated the role of MOR in the proliferation of HCC cell lines and the underlying mechanism. First, RT-PCR, western-blot and immunohistochemistry revealed higher expression of MOR in HCC cells and tissue than in non-tumor cells or adjacent tissue, and elevated expression of MOR was associated with jeopardized survival of HCC patients, as demonstrated by bioinformatic databases. Knockdown of MOR by specific siRNA attenuated the proliferation and migration of HCC cells and this effect could be reversed by rescue experiments, confirming the essential role of MOR in the proliferation of HCC. Moreover, results of colony formation assay, CCK8 test, flow cytometry and western blot suggested that a monoclonal antibody (mAb) specifically against MOR could inhibit proliferation of HepG2 and Huh7 cells via the MOR-CD147-p53-MAPK pathway, and the interaction between MOR and CD147 was verified by immunofluorescence colocalization and co-IP analysis. The mAb against MOR also enhanced the cisplatin-induced apoptosis of HCC cells by downregulating p-ERK, Bcl-2 and upregulating Bax. Taken together, these results suggest that MOR could regulate the proliferation of HCC cells in a CD147-p53-MAPK dependent manner. MOR possesses the potential to be a therapeutic target to treat HCC.

Preclinical and clinical studies into the bioactivity of low-dose naltrexone (LDN) for oncotherapy

Naltrexone (NTX) is a nonspecific opioid antagonist that exerts pharmacological effects on the opioid axis by blocking opioid receptors distributed in cytoplastic and nuclear regions. NTX has been used in opioid use disorder (OUD), immune-associated diseases, alcoholism, obesity, and chronic pain for decades. However, low-dose naltrexone (LDN) also exhibits remarkable inhibition of DNA synthesis, viability, and other functions in numerous cancers and is involved in immune remodeling against tumor invasion and chemical toxicity. The potential anticancer activity of LDN is a focus of basic research. Herein, we summarize the associated studies on LDN oncotherapy to highlight the potential mechanisms and prospective clinical applications.

Identifying Clear Cell Renal Cell Carcinoma Coexpression Networks Associated with Opioid Signaling and Survival

While opioids constitute the major component of perioperative analgesic regimens for surgery in general, a variety of evidence points to an association between perioperative opioid exposure and longer term oncologic outcomes. The mechanistic details underlying these effects are not well understood. In this study, we focused on clear cell renal cell carcinoma (ccRCC) and utilized RNA sequencing and outcome data from both The Cancer Genome Atlas, as well as a local patient cohort to identify survival-associated gene coexpression networks. We then projected drug-induced transcriptional profiles from in vitro cancer cells to predict drug effects on these networks and recurrence-free, cancer-specific, and overall survival. The opioid receptor agonist, leu-enkephalin, was predicted to have antisurvival effects in ccRCC, primarily through Th2 immune- and NRF2-dependent macrophage networks. Conversely, the antagonist, naloxone, was predicted to have prosurvival effects, primarily through angiogenesis, fatty acid metabolism, and hemopoesis pathways. Eight coexpression networks associated with survival endpoints in ccRCC were identified, and master regulators of the transition from the normal to disease state were inferred, a number of which are linked to opioid pathways. These results are the first to suggest a mechanism for opioid effects on cancer outcomes through modulation of survival-associated coexpression networks. While we focus on ccRCC, this methodology may be employed to predict opioid effects on other cancer types and to personalize analgesic regimens in patients with cancer for optimal outcomes. SIGNIFICANCE: This study suggests a possible molecular mechanism for opioid effects on cancer outcomes generally, with implications for personalization of analgesic regimens.

Opioids and cancer prognosis: A summary of the clinical evidence

Pain is a common and devastating symptom among cancer patients. It can be caused by the cancer itself or by certain therapies like surgery, radiation or chemotherapy. Opioids are the first line of treatment for moderate to severe cancer-related pain. Opioids alone or in combination with non-opioid analgesics and adjuvant medications are important components for pain management during the perioperative period for cancer patients. Opioids act on the μ-opioid receptor (MOR), which is expressed in cancer cells and non-malignant cells of the tumor microenvironment. Retrospective studies suggest an association between the expression of MOR in cancers and shorter survival. In addition, recent evidence suggests that opium use and prescription opioids can influence clinical oncological outcomes. In this review, we will summarize the clinical evidence regarding the effect of opioid administration and survival in patients with cancer as well as the current evidence involving MOR expression and cancer progression.

Overview of Genetic Analysis of Human Opioid Receptors

The human μ-opioid receptor gene (OPRM1 ), due to its genetic and structural variation, has been a target of interest in several pharmacogenetic studies. The μ-opioid receptor (MOR ), encoded by OPRM1 , contributes to regulate the analgesic response to pain and also controls the rewarding effects of many drugs of abuse, including opioids, nicotine, and alcohol. Genetic polymorphisms of opioid receptors are candidates for the variability of clinical opioid effects. The non-synonymous polymorphism A118G of the OPRM1 has been repeatedly associated with the efficacy of treatments for pain and various types of dependence. Genetic analysis of human opioid receptors has evidenced the presence of numerous polymorphisms either in exonic or in intronic sequences as well as the presence of synonymous coding variants that may have important effects on transcription, mRNA stability, and splicing, thus affecting gene function despite not directly disrupting any specific residue. Genotyping of opioid receptors is still in its infancy and a relevant progress in this field can be achieved by using advanced gene sequencing techniques described in this review that allow researchers to obtain vast quantities of data on human genomes and transcriptomes in a brief period of time and with affordable costs.

The association of prescription opioid use with incident cancer: A Surveillance, Epidemiology, and End Results-Medicare population-based case-control study

BACKGROUND

Cancer is the second leading cause of death globally, and researchers seek to identify modifiable risk factors Over the past several decades, there has been ongoing debate whether opioids are associated with cancer development, metastasis, or recurrence. Basic science, clinical, and observational studies have produced conflicting results. The authors examined the association between prescription opioids and incident cancers using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. A complex relation was observed between prescription opioids and incident cancer, and cancer site may be an important determinant.

METHODS

By using linked SEER cancer registry and Medicare claims from 2008 through 2013, a case-control study was conducted examining the relation between cancer onset and prior opioid exposure. Logistic regression was used to account for differences between cases and controls for 10 cancer sites.

RESULTS

Of the population studied (n = 348,319), 34% were prescribed opioids, 79.5% were white, 36.9% were dually eligible (for both Medicare and Medicaid), 13% lived in a rural area, 52.7% had ≥1 comorbidity, and 16% had a smoking-related diagnosis. Patients exposed to opioids had a lower odds ratio (OR) associated with breast cancer (adjusted OR, 0.96; 95% CI, 0.92-0.99) and colon cancer (adjusted OR, 0.90; 95% CI, 0.86-0.93) compared with controls. Higher ORs for kidney cancer, leukemia, liver cancer, lung cancer, and lymphoma, ranging from lung cancer (OR, 1.04; 95% CI, 1.01-1.07) to liver cancer (OR, 1.19; 95% CI, 1.08-1.31), were present in the exposed population.

CONCLUSIONS

The current results suggest that an association exists between prescription opioids and incident cancer and that cancer site may play an important role. These findings can direct future research on specific patient populations that may benefit or be harmed by prescription opioid exposure.

Impact of Pain, Opioids, and the Mu-opioid Receptor on Progression and Survival in Patients With Newly Diagnosed Stage IV Pancreatic Cancer

OBJECTIVES

Pancreatic adenocarcinoma is frequently associated with pain requiring opioid therapy. Opioids, however, have been implicated in causing tumor progression, ultimately shortening survival. We examined the impact of pain, opioid use, and the mu-opioid receptor (MOP-R) expression in tumor tissue on progression-free survival and overall survival of patients with metastatic pancreatic cancer.

METHODS

We identified 103 patients with metastatic pancreatic adenocarcinoma receiving chemotherapy and abstracted data from Tumor Registry, in addition to pain, opioid exposure, carbohydrate antigen 19-9 values, survival, and imaging response. MOP-R expression was evaluated using an immunohistochemistry assay. The association of variables with progression-free survival and overall survival was analyzed in univariate and multivariate models.

RESULTS

Patients with low opioid use (<5 mg oral morphine equivalent/d) survived longer than patients with high opioid (HO) use (≥5 mg oral morphine equivalent/d) (median overall survival of 315 vs. 150 d; hazard ratio [HR]=1.79; 95% confidence interval [CI]: 1.13, 2.84). This effect persisted on multivariate models (adjusted HR=2.76; 95% CI: 1.39, 5.48). Low opioid patients tended to respond better to treatment than HO patients, based on carbohydrate antigen 19-9. Patients with low MOP-R expression had longer median survival (230 vs. 193 d), though the HR was not significant (1.15; 95% CI: 0.71, 1.88). Baseline pain was not associated with outcomes.

CONCLUSION

In patients with metastatic pancreatic adenocarcinoma, HO use is associated with decreased survival, but the severity of baseline pain and MOP-R expression score in tumor tissue does not correlate with clinical outcomes.

Mu Opioid Receptor 1 (MOR-1) Expression in Colorectal Cancer and Oncological Long-Term Outcomes: A Five-Year Retrospective Longitudinal Cohort Study

Preclinical evidence has shown increased expression of mu opioid receptor 1 (MOR-1) in colorectal cancer although its association with disease-free and overall survival (DFS and OS) has not been investigated. We hypothesized that MOR-1 was overexpressed in tumor samples compared to normal tissue and this was associated with decreased DFS and OS. We carried out a retrospective study assessing the association of MOR-1 tumor expression with long-term outcomes by immunohistochemistry in normal and tumor samples from 174 colorectal cancer patients. The primary endpoint was five years of DFS. Secondary endpoints were five years of OS, the difference in MOR-1 expression between normal and tumor tissue and the occurrence of postoperative complications. Multivariable Cox regression showed no significant association between MOR-1 expression and DFS (HR 0.791, 95% CI 0.603–1.039, p = 0.092). MOR-1 expression was higher in tumor tissue compared to non-tumor tissue. No associations were found between MOR-1 expression and OS or postoperative complications. These findings suggest that although MOR-1 is over-expressed in colorectal cancer samples there is no association to increased risk of recurrence or mortality. Future studies are warranted to elucidate the role of cancer stage, genetic polymorphism, and quantitative assessment of MOR-1 over-expression on long-term outcomes in colorectal cancer.

mu-Opioid Receptor Polymorphisms and Breast Cancer Recurrence in Adult Korean Women Undergoing Breast Cancer Surgery: A Retrospective Study

Background: Genetic variations of mu-opioid receptors are well known to contribute to growth and progression of tumors. The most common single-nucleotide polymorphism (SNP) in the mu-opioid receptor 1 gene (OPRM1) is the A118G mutation. We examined the association between the recurrent breast cancer and genotypes of OPRM1 A118G SNP (AA vs. AG vs. GG) in Korean women population. Methods: We analysed medical records and genetic data of 200 patients aged more than 20 who underwent primary breast cancer surgery from June 2012 to June 2014 and diagnosed recurrent breast cancer from June 2012 to September 2019. Results: The incidence of recurrent breast cancer was 6.1%, 8.2%, and 4.8% in genotype AA, AG and GG, respectively (p=0.780). The incidence of recurrent breast cancer in volatile anaesthesia group was 7.0% and 7.1% in total intravenous anaesthesia (TIVA) group (RR = 0.984, 95% CI = 0.328 - 2.951; p = 0.978). Conclusion: OPRM1 A118G SNP had no influence on breast cancer recurrence in Korean women. Anaesthesia technique did not show significant effect on the incidence of recurrent breast cancer.

A Breast Cancer Survivor's Self-Controlled Case Report: Methylprednisolone Acetate Provided a Week Longer Analgesia Than Dexamethasone Sodium Phosphate via Thoracic Paravertebral Blockade

Proper perioperative pain control with opioid-sparing techniques that extend into post-discharge arena is desirable yet hard to accomplish in breast cancer patients. We here reported a case where we took advantage of long-acting local anesthetics in conjunction with glucocorticoids of different hydrophilic/lipophilic properties and achieved prolonged analgesia for days after single administration thoracic paravertebral blockade. Further exploration into the potential effects of long-acting glucocorticoids in breast cancer patients through peripheral nerve blockage is warranted.

Immunomodulatory Effects of Surgery, Pain, and Opioids in Cancer Patients

Surgery is the mainstay of therapy for canine and human solid cancers. Alarmingly, evidence suggests that the process of surgery may exacerbate metastasis and accelerate the kinetics of cancer progression. Understanding the mechanisms by which cancer progression is accelerated as a result of surgery may provide pharmacologic interventions. This review discusses surgery-induced cancer progression. It focuses on immunomodulatory properties of anesthesia and opioids and evidence that studies evaluating the role of opioids in tumor progression are indicated. It concludes by discussing why companion animals with spontaneously arising cancer are an ideal model for clinical trials to investigate this phenomenon.

Identifying and Treating Opioid Side Effects: The Development of Methylnaltrexone

Methylnaltrexone Reverses Chronic Opioid-induced Constipation: A Randomized, Controlled Trial. By Yuan CS, Foss JF, O'Connor M, Osinski J, Karrison T, Moss J, Roizen MF. JAMA 2000; 130:142-8. Reprinted with permission.

CONTEXT

Constipation is the most common chronic adverse effect of opioid pain medications in patients who require long-term opioid administration, such as patients with advanced cancer, but conventional measures for ameliorating constipation often are insufficient.

OBJECTIVE

To evaluate the efficacy of methylnaltrexone, the first peripheral opioid receptor antagonist, in treating chronic methadone-induced constipation.

DESIGN

Double-blind, randomized, placebo-controlled trial conducted between May 1997 and December 1998.

SETTING

Clinical research center of a university hospital.

PARTICIPANTS

Twenty-two subjects (9 men and 13 women; mean [SD] age, 43.2 [5.5] years) enrolled in a methadone maintenance program and having methadone-induced constipation.

MAIN OUTCOME MEASURES

Laxation response, oral-cecal transit time, and central opioid withdrawal symptoms were compared between the 2 groups.

RESULTS

The 11 subjects in the placebo group showed no laxation response, and all 11 subjects in the intervention group had laxation response after intravenous methylnaltrexone administration (P<.001). The oral-cecal transit times at baseline for subjects in the methylnaltrexone and placebo groups averaged 132.3 and 126.8 minutes, respectively. The average (SD) change in the methylnaltrexone-treated group was -77.7 (37.2) minutes, significantly greater than the average change in the placebo group (-1.4 [12.0] minutes; P<.001). No opioid withdrawal was observed in any subject, and no significant adverse effects were reported by the subjects during the study.

CONCLUSIONS

Our data demonstrate that intravenous methylnaltrexone can induce laxation and reverse slowing of oral cecal-transit time in subjects taking high opioid dosages. Low-dosage methylnaltrexone may have clinical utility in managing opioid-induced constipation.

Opium Use and Risk of Pancreatic Cancer: A Prospective Cohort Study

Background: We examined the association between opium consumption and pancreatic cancer incidence in a large-scale prospective cohort of the general population in northeastern Iran.Methods: A total of 50,045 adults were systematically followed up (median of 7.4 years), and incident cases of pancreatic cancer were identified. Self-reported data on opium consumption was collected at baseline. Cumulative use (-year) was defined as number of nokhods (a local unit, approximately 0.2 g) of opium consumed per day multiplied by number of years consuming. Adjusted HRs and 95% confidence intervals (CIs) for the association between opium consumption and pancreatic cancer were calculated using Cox proportional hazards regression models.Results: Overall, 54 confirmed cases of pancreatic cancer were identified. Opium use of more than 81 nokhod-years (high cumulative use), compared with never use, was strongly associated with pancreatic cancer even after adjustments for multiple potential confounding factors [HR = 3.01; 95% CI, 1.25-7.26]. High cumulative consumption of opium was significantly associated with risk of pancreatic cancer after adjusting for cumulative dose of cigarette smoking [HR = 3.56; 95% CI, 1.49-8.50]. In a sensitivity analysis, we excluded participants (including 2 pancreatic cancer cases) who were recruited within the first 5 years of starting opium consumption; high cumulative use of opium was still associated with pancreatic cancer risk [HR = 2.75; 95% CI, 1.14-6.64].Conclusions: Our results showed a positive association between opium consumption and pancreatic cancer.Impact: This is the first prospective large-scale study to show the association of opium consumption with pancreatic cancer as a risk factor. Cancer Epidemiol Biomarkers Prev; 27(3); 268-73. ©2017 AACR.

Impact of opioid use on health care utilization and survival in patients with newly diagnosed stage IV malignancies

PURPOSE

Patients with advanced cancers frequently experience pain. Opioids are commonly prescribed to treat cancer-related pain, but their use might be associated with undesirable consequences including adverse effects and tumor progression, resulting in increased heath care utilization and shorter survival. We examined these possibilities in a large cohort of patients diagnosed with ten common advanced malignancies.

METHODS

We identified 1386 newly diagnosed patients with stage IV non-hematologic malignancies from 2005 to 2013 and ascertained opioid utilization within 90 days of starting anti-cancer treatment using electronic medical record and tumor registry data. Opioid utilization was stratified into low opioid (LO; < 5 mg oral morphine equivalents (OME)/day) and high opioid (HO; ≥ 5 mg OME/day). Health care utilization included tallies of emergency room, urgent care, and inpatient visits. The association of opioid use, tumor type prognosis, age, and gender with overall survival was analyzed in univariate and multivariate models.

RESULTS

HO use patients (n = 624) had greater health care utilization compared to LO use patients (n = 762; p < 0.05). HO use patients also had shorter survival (median survival, 5.5 vs 12.4 months; p < 0.0001). On multivariate analysis, HO use remained associated with shorter overall survival (HR 1.4; 95% CI, 1.3-1.6; p < 0.0001) after adjusting for age, gender, and prognostic group.

CONCLUSIONS

In advanced cancer patients, HO use is associated with greater health care utilization and shorter survival. Prospective studies using opioid-sparing approaches are indicated, to confirm these retrospective findings and to evaluate if these undesirable effects associated with opioid use can be mitigated.