Increased μ-opioid receptor expression in metastatic lung cancer

Influence of perioperative anaesthetic and analgesic interventions on oncological outcomes: a narrative review

Surgery is an important treatment modality for the majority of solid organ cancers. Unfortunately, cancer recurrence following surgery of curative intent is common, and typically results in refractory disease and patient death. Surgery and other perioperative interventions induce a biological state conducive to the survival and growth of residual cancer cells released from the primary tumour intraoperatively, which may influence the risk of a subsequent metastatic disease. Evidence is accumulating that anaesthetic and analgesic interventions could affect many of these pathophysiological processes, influencing risk of cancer recurrence in either a beneficial or detrimental way. Much of this evidence is from experimental in vitro and in vivo models, with clinical evidence largely limited to retrospective observational studies or post hoc analysis of RCTs originally designed to evaluate non-cancer outcomes. This narrative review summarises the current state of evidence regarding the potential effect of perioperative anaesthetic and analgesic interventions on cancer biology and clinical outcomes. Proving a causal link will require data from prospective RCTs with oncological outcomes as primary endpoints, a number of which will report in the coming years. Until then, there is insufficient evidence to recommend any particular anaesthetic or analgesic technique for patients undergoing tumour resection surgery on the basis that it might alter the risk of recurrence or metastasis.

Nociceptin Receptor Is Overexpressed in Non-small Cell Lung Cancer and Predicts Poor Prognosis

Classic opioid receptors, mu (μ), delta (δ), and kappa (κ), have been reported to be expressed in non-small cell lung cancer (NSCLC) cell lines and tumor tissues and to play a role in tumor prognosis. However, the expression and role of the non-classic opioid receptor, nociceptin receptor (NOP) in cancer are unclear. Our hypothesis was that NOP was also highly expressed in NSCLC tumor tissues and this could be correlated with patients' prognostic characters. Expression of NOP was examined in archived cancer tissues from 129 enrolled NSCLC patients by immunohistochemistry and was further analyzed with the patients' outcomes. NOP expression in NSCLC cell lines was also detected. The dataset from Kaplan-Meier Plotter was used to explore the correlation between the levels of NOP mRNA in cancerous tissue and the prognosis of NSCLC patients. Cell functional assays were performed to detect the effect of NOP activation on tumor aggressive furthers. Results showed NOP expression was highly expressed in cancer tissues and human cancer cell lines. NOP expression was not associated with patients' opioid requirement but closely with some clinicopathological indicators which reflected the malignancy. Moreover, NOP staining level was the independent poor prognostic factor for NSCLC patients receiving lobectomy, which was further verified by determining the mRNA expression levels through the online dataset. In vitro experiments revealed that NOP activation promotes the proliferation and invasion of A549 cells via PI3K/Akt signaling pathway. We conclude that NOP is overexpressed in NSCLC and is inversely correlated with patient's postoperative survival.

Design, synthesis and evaluation of 111In labeled DOTA-conjugated tetrapeptides having high affinity and selectivity for mu opioid receptors

INTRODUCTION

Peripheral mu (μ) opioid receptors are implicated in pain, bowel dysfunction and the progression of certain cancers. In an effort to identify radioligands well suited for imaging these peripheral sites, we have prepared and evaluated four hydrophilic ¹¹¹In labeled DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) conjugated μ tetrapeptides.

METHODS

Peptides were prepared by solid-phase techniques, using orthogonal strategies to achieve branching to DOTA, and then characterized by HPLC, mass spectroscopy and amino acid analysis. Scaffolds included novel peptide H-Dmt-D-Ala-Phe-Orn-NH₂ (DAPO), where Dmt = 2',6'-dimethyltyrosine, and known peptide H-Dmt-D-Arg-Phe-Lys-NH₂ ([Dmt¹]DALDA). Constructs had DOTA conjugation at the Orn⁴ or Lys⁴ side chains, or to the C-terminal through a hexanoic acid-lysine linker. Indium(III) complexation and ¹¹¹In radiolabeling were accomplished by standard methods. Protein binding and Log D_7.4 were determined. Binding and pharmacological profiles were obtained in vitro. Biodistribution and radiometabolite studies were conducted using male CD-1 mice.

RESULTS

All four indium(III)-DOTA conjugates derived from DAPO and [Dmt¹]DALDA showed good selectivity and subnanomolar affinity for μ opioid receptors. One radioligand, H-Dmt-D-Ala-Phe-Orn(δ-[¹¹¹In]In-DOTA)-NH₂, showed 25% specific binding in vivo to μ sites in mouse gut. Notably, this was the least polar of the series, and also showed low sensitivity to modulation of binding by sodium ions. All radioligands showed high kidney uptake of radiometabolites.

CONCLUSIONS

Visualizing peripheral μ opioid receptors using ¹¹¹In labeled DOTA-conjugated tetrapeptides appears feasible, but structural modifications to enhance specific binding and metabolic stability, as well as to reduce kidney uptake, will be required.

ADVANCES IN KNOWLEDGE

This study shows in vivo labeling of peripheral μ opioid receptors by a tetrapeptide radioligand, and provides information that should prove useful in the design of peptide radioligands having optimal properties.

The effect of anesthetic technique on µ-opioid receptor expression and immune cell infiltration in breast cancer

BACKGROUND

Clinical histological studies demonstrate that the distribution of natural killer (NK) cells, other immune cells and μ-opioid receptors (MOR) within cancer tissue can predict cancer prognosis. No clinical study has evaluated whether anesthetic technique influences immune cell and MOR expression within human breast cancer.

METHODS

Excised preoperative biopsies and intraoperative breast cancer specimens from 20 patients randomly chosen from patients previously enrolled in an ongoing, prospective, randomized trial (NCT00418457) investigating the effect of anesthetic technique on long-term breast cancer outcome were immunohistochemically stained and microscopically examined by two independent investigators, masked to randomization, to quantify MOR and immune cell infiltration: CD56, CD57 (NK cells), CD4 (T helper cells), CD8 (cytotoxic T cells) and CD68 (macrophages). Patients had been randomized to receive either a propofol-paravertebral anesthetic with continuing analgesia (PPA, n = 10) or balanced general anesthetic with opioid analgesia (GA, n = 10).

RESULTS

There were no differences between the groups in staining intensity in preoperative biopsy specimens. Expression intensity values (median 25-75%) for MOR in intraoperative resected biopsy were higher in GA 8.5 (3-17) versus PPA 1 (0-10), p = 0.04. The numbers of MOR-positive cells were also higher in GA patients. Expression and absolute numbers of CD56, CD57, CD4 and CD68 were similar in resected tumor in both groups.

CONCLUSION

General anesthesia with opioid analgesia increased resected tumor MOR expression compared with propofol-paravertebral anesthetic technique, but the anesthetic technique did not significantly influence the expression of immune cell markers.

Low Dose Naltrexone and Lung Cancer: A Case Report and Discussion

Low dose naltrexone (LDN) has been promising as a complementary medication for patients with a broad range of medical disorders. Although not a proven cure, evidence from clinical trials supports LDN as being a valuable adjunct for disorders in which the immune system plays a centralized role. Additionally, clinical trials have proposed a unique mechanism(s) allowing LDN to affect tumors including non-small cell lung cancer (NSCLC) at the cellular level by augmenting the immune system. We present a case of a 50-year-old male with a prolonged survival and a past medical history of prostate and lung cancer.

Opioid Dose and Survival of Patients with Incurable Nonsmall Cell Lung Cancer: A Prospective Cohort Study

BACKGROUND

Preclinical studies show that opioids promote angiogenesis, tumor progression, and metastasis, resulting in shorter survival.

OBJECTIVE

To explore whether opioids are associated with the overall survival (OS) of patients with incurable nonsmall cell lung cancer (NSCLC).

DESIGN

Prospective cohort study of patients with NSCLC.

SETTING

We investigated patients newly diagnosed with advanced or post-operative recurrent NSCLC between April 2013 and December 2015 at a single institute.

MEASUREMENTS

We evaluated OS, opioid requirements, opioid doses, pain levels, and prognostic factors of advanced NSCLC. The effects of variables on survival were analyzed using univariable and multivariable models. Patients were stratified according to oral morphine equivalents (OMEs)/day (<60 or ≥60 mg) to assess the association between opioid dose and OS.

RESULTS

We analyzed 150 patients, including 64 who received opioid treatment during follow-up. The median OS was 242 days in the opioid group and 627 days in the no-opioid group (log-rank p < 0.001). Multivariable models revealed that the opioid requirement was an independent predictor of shorter OS, after adjustment for prognostic variables, including sex, histology, stage, history of systemic chemotherapy, and performance status (hazard ratio 1.73, 95% confidence interval 1.137-2.631). There was no significant difference in OS between patients who received ≥60 mg OME/day for 250 days versus <60 OME/day for 242 days.

CONCLUSIONS

The opioid dose does not shorten the survival of patients with advanced NSCLC. The opioid requirement is associated with shorter survival when opioids are administered any time during the clinical course, independent of the influence of other key factors.

Oncologic Equivalence of Minimally Invasive Lobectomy: The Scientific and Practical Arguments

BACKGROUND

Despite the slow adoption of minimally invasive lobectomy (MIL), it is now a preferred approach for early lung cancer. Nevertheless, ongoing concerns about MIL oncologic effectiveness has led to calls for prospective, randomized trials.

METHODS

Retrospective analysis of on-line databases, collected readings, and other scholarly experiences of the experienced authors were used to construct this review. All available reports that contained long-term survival comparisons for open versus MIL were tabulated.

RESULTS

The preponderance of limited randomized and numerous large propensity-matched database analyses indicate equivalent or improved long-term MIL survival for early-stage disease. MIL lymph node dissection quality has been challenged; however, this was attributed to MIL avoidance of central tumors in early reports. Although technical inadequacies for MIL should be amplified for advanced cancer resections, early reports show no such concern. In fact, for special populations such as older, frail patients, evidence is much stronger that MIL confers a survival advantage.

CONCLUSIONS

MIL is an oncologically equivalent operation with substantially less morbidity, especially in frail populations. It is reasonable to suggest that MIL should be the technique of choice, even a quality indicator, for lobectomy.

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.

Effects of surgery and anesthetic choice on immunosuppression and cancer recurrence

Background

The relationship between surgery and anesthetic-induced immunosuppression and cancer recurrence remains unresolved. Surgery and anesthesia stimulate the hypothalamic–pituitary–adrenal (HPA) axis and sympathetic nervous system (SNS) to cause immunosuppression through several tumor-derived soluble factors. The potential impact of surgery and anesthesia on cancer recurrence was reviewed to provide guidance for cancer surgical treatment.

Methods

PubMed was searched up to December 31, 2016 using search terms such as, “anesthetic technique and cancer recurrence,” “regional anesthesia and cancer recurrence,” “local anesthesia and cancer recurrence,” “anesthetic technique and immunosuppression,” and “anesthetic technique and oncologic surgery.”

Results

Surgery-induced stress responses and surgical manipulation enhance tumor metastasis via release of angiogenic factors and suppression of natural killer (NK) cells and cell-mediated immunity. Intravenous agents such as ketamine and thiopental suppress NK cell activity, whereas propofol does not. Ketamine induces T-lymphocyte apoptosis but midazolam does not affect cytotoxic T-lymphocytes. Volatile anesthetics suppress NK cell activity, induce T-lymphocyte apoptosis, and enhance angiogenesis through hypoxia inducible factor-1α (HIF-1α) activity. Opioids suppress NK cell activity and increase regulatory T cells.

Conclusion

Local anesthetics such as lidocaine increase NK cell activity. Anesthetics such as propofol and locoregional anesthesia, which decrease surgery-induced neuroendocrine responses through HPA-axis and SNS suppression, may cause less immunosuppression and recurrence of certain types of cancer compared to volatile anesthetics and opioids.

Methadone as a "Tumor Theralgesic" against Cancer

Methadone has beneficial characteristics as an analgesic against cancer pain, including high bioavailability, multiple receptor affinities, and lack of active metabolites that might induce adverse side effects. However, methadone has an own pharmacological profile that should be considered in the treatment of cancer patients. There is evidence from preclinical studies that methadone could also elicit antitumor activity by downregulating the threshold of apoptosis and to enhance the effects of different chemotherapeutic agents. This confirms the concept of using methadone as a chemosensitizer in the future treatment of cancer. Our article discusses major issues about the role of methadone as a possible “tumor theralgesic,” combining tumor therapeutic and analgesic activities.

Anesthetic technique and cancer recurrence in oncologic surgery: unraveling the puzzle

Surgery/anesthetic technique-stimulated immunosuppression in the perioperative period might cause an increase in cancer-related mortality. Whether anesthetic technique can affect the outcomes of cancer patients remains inconclusive. This review discusses data from the available literature on anesthetic techniques applied in oncologic surgery, the long-term outcomes of anesthetic technique, and their relation to survival and cancer recurrence. Searches of the PubMed database up to June 30, 2016, were conducted to identify publications with the terms "anesthetic technique and cancer recurrence," "regional anesthesia and cancer recurrence," "local anesthesia and cancer recurrence," "anesthetic technique and immunosuppression," and "anesthetic technique and oncologic surgery." Surgery/anesthesia-stimulated activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS) provides immunosuppression through several soluble factors. Volatile anesthetics and opioids suppress cell-mediated immunity (CMI) and promote the proliferation of cancer cells and angiogenesis, whereas propofol does not suppress CMI and inhibits tumor angiogenesis. Regional anesthesia (RA) protects CMI and diminishes the surgical neuroendocrine stress response by blocking afferent neural transmission that stimulates the HPA axis and SNS, decreasing the requirement for opioids and volatile anesthetics and thereby decreasing cancer recurrence. Preclinical and retrospective studies highlight a potential benefit of anesthetic technique in reducing cancer-related mortality and recurrence by attenuating immunosuppression following surgical treatment in patients with specific types of cancer. Several well-planned, prospective, randomized controlled trials (RCTs) are underway that may provide more conclusive and definitive results regarding the benefits of anesthetic technique on survival in oncologic surgery.

Does Opioid Use Cause Angiogenesis and Metastasis?

Objective

To provide a comprehensive overview of the potential for morphine to lead to angiogenesis and metastasis.

Background

Morphine is often the treatment of choice for severe cancer-related pain. Small studies have been emerging that indicate that opioids may influence angiogenesis and metastasis, but this has not yet been comprehensively synthesized.

Purpose

To highlight morphine's relationship with angiogenesis and metastasis in in vitro models.

Method

A review of the literature was conducted using PubMed (1966 to 2015) and Cochrane Library (1987 to 2015) electronic databases. The search, as well as consultation with experts, yielded 84 articles for initial review, 12 of which met inclusion for review. Possible theories of the underlying etiology of the metastasis and angiogenesis were recorded.

Results

All studies were assessed using the PRISMA checklist.

Conclusion

This systematic review demonstrates that morphine has a potential causal relationship with angiogenesis and metastasis. This is likely due to multiple etiologies, including immunosuppressive, pro-inflammatory, and pro-angiogenetic.

Down-regulation of the tumour suppressor κ-opioid receptor predicts poor prognosis in hepatocellular carcinoma patients

BACKGROUND

Opioid receptors have become increasingly implicated in cancer progression and long-term patient outcomes. However, the expression and significance of the κ-opioid receptor (KOR) in hepatocellular carcinoma (HCC) remain unclear.

METHODS

In this study, KOR mRNA expression was analysed by real-time quantitative PCR in 64 pairs of HCC tumour tissues and adjacent non-tumour tissues, and KOR protein expression was analysed by immunohistochemistry in 174 HCC patients. We investigated the correlation between KOR expression and clinicopathological parameters to illustrate the potential prognostic significance of KOR expression in HCC.

RESULTS

KOR mRNA expression was significantly down-regulated in 79.69% (51 of 64) of the HCC tumour samples, and KOR expression in tumour tissue was significantly lower than that in adjacent non-tumour tissues (P < 0.001). ROC curve analysis showed that KOR mRNA expression yielded AUC of 0.745, for the detection of HCC patients. Low KOR mRNA expression in HCC was correlated with aggressive clinicopathological parameters, such as tumour size (P = 0.015), differentiation grade (P = 0.011), and TNM stage (P = 0.021). Moreover, down-regulation of KOR protein expression in HCC tissues was detected in 174 HCC patients. Similarly, negative KOR protein expression was significantly correlated with aggressive clinicopathological features, such as tumour size (P = 0.002), vascular invasion (P = 0.003), differentiation grade (P = 0.026), and TNM stage (P = 0.030). Furthermore, Kaplan-Meier survival analysis demonstrated that down-regulation of KOR in HCC indicated poor prognosis. KOR deficiency (KOR^T < N) was correlated to a shorter survival rate and an increased recurrence (both P < 0.001). In univariate and multivariate survival analyses, KOR was identified as a promising independent risk factor for both overall survival (OS, both P < 0.001) and recurrence-free survival (RFS, both P < 0.001).

CONCLUSIONS

Down-regulation of KOR in HCC tumour tissues has a strong association with poor prognosis and KOR might be a potential tumour suppressor.

Influence of opioids on immune function in patients with cancer pain: from bench to bedside

In patients with cancer, opioids are principally used for the management of acute surgical and chronic cancer-related pain. However, opioids have many non-analgesic effects, including direct and indirect effects on cancer cells and on anti-tumour immunity (NK cells, macrophages and T-cells). Direct effects on immune cells are manifested via opioid and non-opioid toll-like receptors, whereas indirect effects are manifested via the sympathetic nervous system and hypothalamic-pituitary-adrenal axis. Opioids can also decrease/alter immune cell infiltration into the tumour micro-environment. Animal models have shown that this is not a class effect, in that morphine and fentanyl suppress NK cell cytotoxicity; buprenorphine does not affect NK cell cytotoxicity, whereas tramadol increases NK cell cytotoxicity, reducing metastasis. In healthy individuals, morphine suppresses and fentanyl enhances NK cell cytotoxicity. In patients undergoing surgery, fentanyl decreased and tramadol increased NK cell cytotoxicity; clinical outcomes were not determined. Meta-analyses of opioid-sparing surgical studies report an association between improved recurrence-free and/or overall survival with regional/neuraxial anaesthesia compared with systemic opioids. In patients receiving opioids for non-surgical cancer-related pain, morphine has variable effects on immunity; clinical outcomes were not assessed. Although there is a potential association between systemic opioid administration and shorter survival in cancer patients with a prognosis of months to years, studies have not been designed to primarily assess survival, as a consequence of which causality cannot be apportioned. Pain is immunosuppressive, so analgesia is important. Opioids for cancer-related pain will continue to be recommended until definitive data on the effects of opioids on clinical outcomes in specific patient groups becomes available.

LINKED ARTICLES

This article is part of a themed section on Emerging Areas of Opioid Pharmacology. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.14/issuetoc.

Morphine Suppresses Lung Cancer Cell Proliferation Through the Interaction with Opioid Growth Factor Receptor: An In Vitro and Human Lung Tissue Study

BACKGROUND

There have been inconsistent reports on whether opioids promote or inhibit lung cancer growth. In this study, we suggest that opioid growth factor receptor (OGFR), a negative regulator of cell proliferation, is a binding site of morphine and is involved in subsequent morphine-induced lung cancer growth suppression.

METHODS

The expression and distribution of OGFR in human lung cancer tissues and cell lines were assessed with immunohistochemistry and real-time reverse transcription polymerase chain reaction. The human lung cancer cell line, H1975 (adenocarcinoma), which overexpressed OGFR but not μ-opioid receptors, was selected for further analysis to verify the interaction between morphine and OGFR and the impact of morphine on cancer cell growth.

RESULTS

OGFR was expressed in lung cancer tissues and all cancer cell lines tested. Adenocarcinoma showed a higher OGFR expression than squamous cell carcinoma (reverse transcription polymerase chain reaction relative quantitation value: median [interquartile range], 13.1 [9.3-20.0] vs 4.3 [2.2-6.6]; P = 0.003). OGFR expression showed an inverse correlation with cell proliferation (r = -0.92, P = 0.0001). Morphine treatment reduced the median H1975 cell number by approximately 23% (P = 0.03). Growth suppression by morphine was attenuated when OGFR was knocked down. A confocal experiment demonstrated binding of morphine to OGFR. Growth suppression by morphine occurred in the S phase of the cell cycle.

CONCLUSIONS

Lung cancer tissues and cell lines express OGFR. Morphine interacts with OGFR and may suppress lung cancer progression.

The Effects of Anesthetics on Recurrence and Metastasis of Cancer, and Clinical Implications

Surgical resection of the primary tumor may enhance the metastasis and recurrence of cancer. The reaction of patients to surgery includes changes of the immune system, the inflammatory system and the neuroendocrine system. In the perioperative period, anesthetics are used both for anesthesia and analgesia. There are several studies showing that the progression of cancer can be influenced by many kinds of anesthetics, although most of these studies are preclinical and thus have not yet influenced clinical recommendations. This review summarizes recent studies regarding the effects of anesthetics on metastasis and recurrence of cancer.

Expression of anaesthetic and analgesic drug target genes in excised breast tumour tissue: Association with clinical disease recurrence or metastasis

Background

Retrospective analyses suggest anaesthetic-analgesics technique during cancer surgery may affect recurrence/metastasis. This could involve direct effects of anaesthetic-analgesic drugs on cancer cells. While μ-opioid receptor over-expression in lung tumours is associated with greater metastasis, other anaesthetic-analgesic receptor targets in cancer recurrence/metastasis remain unexplored. Therefore, we evaluated the association between genetic expression of anaesthetic-analgesic receptor targets and recurrence/metastasis, using a repository of breast cancer gene expression and matching clinical data.

Methods

A list of 23 genes encoding for the most prominent anaesthetic-analgesic receptor targets was compiled. This was processed through BreastMark- an algorithm integrating gene expression data from ~17,000 samples and clinical data from >4,500 breast cancer samples. Gene expression data was dichotomized using disease-free survival (survival without recurrence) and distant disease-free survival (survival without metastasis) as end points. Hazard ratios were calculated by Cox-regression analysis. Enrichment for prognostic markers was determined by randomly choosing 23-member gene lists from all available genes, calculating how often >5 significant markers were observed and adjusting p-values for multiple testing. This was repeated 10,000 times and an empirical p-value calculated.

Results

Of 23 selected genes, 9 were significantly associated with altered rates of metastasis and 4 with recurrence on univariate analysis. Adjusting for multiple testing, 5 of these 9 genes remained significantly associated with metastasis, non with recurrence. This ratio of genes (5/23) was not significantly enriched for markers of metastasis (p = 0.07).

Conclusion

Several anaesthetic-analgesic receptor genes were associated with metastatic spread in breast cancer. Overall there was no significant enrichment in prognostic markers of metastasis, although a trend was observed.

A systematic review of the impact of pain on overall survival in patients with cancer

PURPOSE

Pain commonly occurs in cancer patients, and has been associated with shorter survival. However, the importance of pain is less clear when analyzed with other known prognostic variables. This systematic review was performed to better understand how pain impacts overall survival (OS) in common cancers when key clinical variables are included in multivariate analysis.

METHODS

A Medline search was completed to find studies examining the relationship between pain, clinical variables, and OS in patients with breast, colorectal, lung, or prostate cancer. Multivariate analysis included known prognostic variables including age, performance status, disease burden, and laboratory parameters.

RESULTS

Fifty studies met inclusion criteria. In patients with breast, colorectal, and lung cancer, pain was not a significant prognostic factor for OS on multivariate analysis in most studies. In contrast, several studies suggest that pain is an independent prognostic factor for OS in advanced prostate cancer, even when relevant clinical prognostic variables are included. However, analgesic use was often used as a surrogate for prostate cancer pain, making it difficult to determine whether pain or opioid exposure was more important in influencing survival.

CONCLUSIONS

Pain may be associated with shorter survival in patients with cancer, but the mechanism for this relationship is unknown. The available evidence is insufficient to definitively determine if pain independently influences survival in patients with breast, colorectal, or lung cancer. The majority of studies in prostate cancer show pain to be an independent prognostic factor for OS, and often also incorporate opioid analgesic use in multivariate analysis. Prospective studies are needed to better understand how opioid utilization and pain may affect cancer progression and survival in diverse malignancies.

Can anesthetic-analgesic technique during primary cancer surgery affect recurrence or metastasis?

PURPOSE

Mortality among cancer patients is more commonly due to the effects of metastasis and recurrence as opposed to the primary tumour. Various perioperative factors have been implicated in tumour growth, including anesthetic agents and analgesia techniques. In this narrative review, we integrate this information to present a summary of the best available evidence to guide the conduct of anesthesia for primary cancer surgery.

SOURCE

We conducted a search of the PubMed database up to May 31, 2015 to identify relevant literature using the search terms "anesthesia and metastases", "anesthetic drugs and cancer", "volatile anesthetic agents and cancer", and "anesthetic technique and cancer".

PRINCIPAL FINDINGS

There is conflicting evidence regarding volatile agents; however, the majority of studies are in vitro, suggesting that these agents are associated with enhanced expression of tumourigenic markers as well as both proliferation and migration of cancer cells. Nitrous oxide has not been shown to have any effect on cancer recurrence. Local anesthetic agents may reduce the incidence of cancer recurrence through systemic anti-inflammatory action in addition to direct effects on the proliferation and migration of cancer cells. Nonsteroidal anti-inflammatory drugs affect cancer cells via inhibition of cyclooxygenase 2 (COX-2), which leads to reduced resistance of the cancer cell to apoptosis and reduced production of prostaglandins by cancer cells. Nonsteroidal anti-inflammatory drugs also suppress the cancer cell growth cycle through effects independent of COX-2 inhibition. Opioids have been shown to inhibit the function of natural killer cells and to stimulate cancer cell proliferation through effects on angiogenesis and tumour cell signalling pathways. Supplemental oxygen at the time of surgery has a proangiogenic effect on micrometastases, while the use of perioperative dexamethasone does not affect overall rates of cancer survival.

CONCLUSIONS

Current laboratory research suggests that perioperative interventions may impact recurrence or metastasis through effects on cancer cell signalling, the immune response, or modulation of the neuroendocrine stress response. Further evidence is awaited from prospective randomized-controlled trials. Meanwhile, with limited data upon which to make strong recommendations, anesthesiologists should seek optimal anesthesia and analgesia for their patients based on individual risk-benefit analysis and best available evidence on outcomes other than cancer recurrence.

Molecular signatures of mu opioid receptor and somatostatin receptor 2 in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC), a particularly aggressive malignancy, has been linked to atypical levels, certain mutations, and aberrant signaling of G-protein-coupled receptors (GPCRs). GPCRs have been challenging to target in cancer because they organize into complex networks in tumor cells. To dissect such networks with nanometer-scale precision, here we combine traditional biochemical approaches with superresolution microscopy methods. A novel interaction specific to PDAC is identified between mu opioid receptor (MOR) and somatostatin receptor 2 (SSTR2). Although MOR and SSTR2 did not colocalize in healthy pancreatic cells or matching healthy patient tissues, the pair did significantly colocalize in pancreatic cancer cells, multicellular tumor spheroids, and cancerous patient tissues. Moreover, this association in pancreatic cancer cells correlated with functional cross-talk and increased metastatic potential of cells. Coactivation of MOR and SSTR2 in PDAC cells led to increased expression of mesenchymal markers and decreased expression of an epithelial marker. Together these results suggest that the MOR-SSTR2 heteromer may constitute a novel therapeutic target for PDAC.

Treatment with methylnaltrexone is associated with increased survival in patients with advanced cancer

BACKGROUND

Methylnaltrexone (MNTX), a peripherally acting μ-opioid receptor (MOR) antagonist, is FDA-approved for treatment of opioid-induced constipation (OIC). Preclinical data suggest that MOR activation can play a role in cancer progression and can be a target for anticancer therapy.

PATIENTS AND METHODS

Pooled data from advanced end-stage cancer patients with OIC, despite laxatives, treated in two randomized (phase III and IV), placebo-controlled trials with MNTX were analyzed for overall survival (OS) in an unplanned post hoc analysis. MNTX or placebo was given subcutaneously during the double-blinded phase, which was followed by the open-label phase, allowing MNTX treatment irrespective of initial randomization.

RESULTS

In two randomized, controlled trials, 229 cancer patients were randomized to MNTX (117, 51%) or placebo (112, 49%). Distribution of patients' characteristics and major tumor types did not significantly differ between arms. Treatment with MNTX compared with placebo [76 days, 95% confidence interval (CI) 43-109 versus 56 days, 95% CI 43-69; P = 0.033] and response (laxation) to treatment compared with no response (118 days, 95% CI 59-177 versus 55 days, 95% CI 40-70; P < 0.001) had a longer median OS, despite 56 (50%) of 112 patients ultimately crossing over from placebo to MNTX. Multivariable analysis demonstrated that response to therapy [hazard ratio (HR) 0.47, 95% CI 0.29-0.76; P = 0.002) and albumin ≥3.5 (HR 0.46, 95% CI 0.30-0.69; P < 0.001) were independent prognostic factors for increased OS. Of interest, there was no difference in OS between MNTX and placebo in 134 patients with advanced illness other than cancer treated in these randomized studies (P = 0.88).

CONCLUSION

This unplanned post hoc analysis of two randomized trials demonstrates that treatment with MNTX and, even more so, response to MNTX are associated with increased OS, which supports the preclinical hypothesis that MOR can play a role in cancer progression. Targeting MOR with MNTX warrants further investigation in cancer therapy.

CLINICAL TRIALS NUMBER

NCT00401362, NCT00672477.

Synthesis and evaluation of a ligand targeting the μ and δ opioid receptors for drug delivery to lung cancer

A well-established approach to developing new imaging agents and treatments for cancer begins with the recognition of receptors that are overexpressed in cancer cells. Ideally, these same receptors would also be absent, or minimally expressed, in healthy tissue. The mu (μ) and delta (δ) opioid receptors (MOR and DOR respectively) match these criteria, with expression in cancer cells that is higher than primary lung epithelial cells. Naltrexone is a drug approved by the U.S. Food and Drug Administration (FDA) for treatment of alcohol dependence or prevention of relapse from opioid addiction. Since naltrexone binds with high affinity to both MOR and DOR, it was selected as the platform for development of novel ligands capable of delivering a cytotoxic payload to non-small cell lung cancer (NSCLC). This study outlines the synthesis of two ligands, with peptide or PEG linkers that were synthesized from 6-amino-naltrexone and conjugated with rhodamine dye or ^99mTc for in vitro imaging, binding affinity or in vivo imaging and biodistribution studies. Transfected HEK cells were used as a model system for over-expression of the μ-opioid receptor (MOR) or the δ-opioid receptor (DOR). Naltrexone and naltrindole were used as competition for MOR and DOR respectively during the binding affinity studies. Mice bearing a xenograft of HEK cells transfected with μ (HEK-mu) or δ (HEK-delta) opioid receptors were the animal model used for PET imaging and in vivo biodistribution studies. Although the binding affinity studies were encouraging, the biodistribution data for the selected conjugates lacked sufficient specificity. These conjugates were abandoned from further development but information about their synthesis may be valuable to other laboratories working in this field.

[Application of thoracic paravertebral nerve block in video-assisted thoracosopic surgery: a randomized controlled trial]

OBJECTIVE

To investigate the effect of a single dose of ropivacaine combined with sufentanilfor thoracic paravertebral block (TPVB) on pain and enhanced recovery after surgery (ERAS) in patients undergoing video-assisted thoracosopic surgery.

METHODS

Sixty patients undergoing video-assisted thoracosopic surgery were randomly divided into three groups to receive intravenous combined general anesthesia (group C), a single dose of ropivacainefor thoracic paravertebral block before surgery combined with intravenous and general anesthesia(group T₁), or a single dose of ropivacaineand sufentanilfor thoracic paravertebral blockcombined with intravenous and general anesthesia (group T₂). None of the patients used postoperative analgesia pump, and tramadol hydrochoride injection (100 mg) was given in cases with NRS scores > 4 after the surgery. The data were recorded including analgesics used for nerve block before the operation, intravenous dosage of sufentanilduring operation, total dose of sufentanilused (intravenous+nerve block), intravenous remifentanil dose during operation, NRS scores at 4, 6, 24, 48 h after the surgery, rescue analgesia in the first postoperative 24 h after surgery, ICU stay and hospital stay after the surgery.

RESULTS

Compared with those in group C, the intravenous sufentanildose, total sufentanildose, intravenous remifentanildose during operation, NRS scores at 4 and 6, 24 h, and ICU stay and hospital stay after the surgery were significantly decreased in groups T₁ and T₂ (P<0.05). The total dose of opioids during the operation and NRS scores at 4 and 6 h were significantly lower in group T₂ than in group T₁ (P<0.05), but the total dose of sufentanil, ICU stay and hospital stay were simialr between the two groups.

CONCLUSION

A single dose of ropivacaine combined with sufentanilfor thoracic paravertebral blockbefore surgery can reduce the total dose opioids, produce the optimal analgesic effect, and promote postoperative recovery of the patients.

Morphine, a potential antagonist of cisplatin cytotoxicity, inhibits cisplatin-induced apoptosis and suppression of tumor growth in nasopharyngeal carcinoma xenografts

Morphine is an opioid analgesic drug often used for pain relief in cancer patients. However, there is growing evidence that morphine may modulate tumor growth, progression and metastasis. In this study, we evaluated whether morphine modulates cisplatin-induced apoptosis in human nasopharyngeal carcinoma CNE-2 cells and whether morphine affects the antitumor activity of cisplatin on tumor growth in human nasopharyngeal carcinoma CNE-2 xenografts in nude mice. We showed that a pretreatment with morphine (1 μg/ml) inhibited the sensitivity of CNE-2 cells to cisplatin by inhibiting cisplatin-induced CNE-2 cell apoptosis, decreasing caspase-3 activity and increasing the Bcl-2/Bax ratio. However, a high dose of morphine (1000 μg/ml) had the opposite effect. We also showed that at a low dose, morphine enhances chemoresistance in an in vivo nasopharyngeal carcinoma (NPC) model by inhibiting cisplatin-induced apoptosis and decreasing neovascularization. Taken together, our results indicate that a low dose of morphine may lead to chemoresistance of cisplatin in NPC models in vitro and in vivo by inhibiting cisplatin-induced apoptosis and decreasing neovascularization.

Endogenous opiates and behavior: 2014

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).

Opioid System Modulates the Immune Function: A Review

Opioid receptors and their ligands produce powerful analgesia that is effective in perioperative period and chronic pain managements accompanied with various side effects including respiratory depression, constipation and addiction etc. Opioids can also interfere with the immune system, not only participating in the function of the immune cells, but also modulating innate and acquired immune responses. The traditional notion of opioids is immunosuppressive. Recent studies indicate that the role of opioid receptors on immune function is complicated, working through various different mechanisms. Different opioids or opioids administrations show various effects on the immune system: immunosuppressive, immunostimulatory, or dual effect. It is important to elucidate the relationship between opioids and immune function, since immune system plays critical role in various physiological and pathophysiological processes, including the inflammation, tumor growth and metastasis, drug abuse, and so on. This review article tends to have an overview of the recent work and perspectives on opioids and the immune function.

Effect of mu Agonists on Long-Term Survival and Recurrence in Nonsmall Cell Lung Cancer Patients

Opioids are widely used for postoperative analgesia. Morphine may have an effect on cell replication, migration, and cancer recurrence. However, the association of postoperative mu agonists with outcome of nonsmall cell lung cancer (NSCLC) patients has not been fully investigated.We retrospectively evaluated the impact of postoperative mu agonists on overall survival (OS) and disease-free survival (DFS) in early stage NSCLC patients. Patients and relevant medical information were selected from the Bio-Bank of Shandong Provincial Hospital. Difference of clinicopathologic information in postoperative mu agonists group and no mu agonists group was analyzed by χ test. Univariate and multivariate Cox regression analysis were conducted and represented as hazards ratio and 95% confidence interval form. The primary endpoint was OS and secondary endpoint was DFS.This retrospective study included 984 consecutive NSCLC patients who underwent surgery between January 2006 and December 2011. No significant difference existed between postoperative mu agonists usage group and no mu agonists usage group in clinicopathologic information except operation type (P = 0.041). Postoperative mu agonists usage was related to shorter OS (HR 1.514, 95% CI 1.197-1.916, P = 0.001) and shorter DFS (HR 1.415, 95% CI 1.123-1.781, P = 0.003) in the multivariate Cox regression model. For the patients who received postoperative chemotherapy or radiotherapy postoperative mu agonists also predict shorter survival (HR 1.437, 95% CI 1.041-1.982, P = 0.027). Subgroup analysis showed that administration of postoperative mu agonists was related to shorter OS, especially in males, more smoking, poor differential degree, bilobectomy or pneumonectomy, and stage III subgroup, respectively.Administration of postoperative mu agonists was related to shorter OS and DFS for the NSCLC patients who underwent surgery.

The mu opioid receptor: A new target for cancer therapy?

Mu opioids are among the most widely used drugs for patients with cancer with both acute and chronic pain as well as in the perioperative period. Several retrospective studies have suggested that opioid use might promote tumor progression and as a result negatively impact survival in patients with advanced cancer; however, in the absence of appropriate prospective validation, any changes in recommendations for opioid use are not warranted. In this review, the authors present preclinical and clinical data that support their hypothesis that the mu opioid receptor is a potential target for cancer therapy because of its plausible role in tumor progression. The authors also propose the hypothesis that peripheral opioid antagonists such as methylnaltrexone, which reverses the peripheral effects of mu opioids but maintains centrally mediated analgesia and is approved by the US Food and Drug Administration for the treatment of opioid-induced constipation, can be used to target the mu opioid receptor.

MOR1 expression in gastric cancer: a biomarker associated with poor outcome

BACKGROUND

At present, the expression of MOR1 and its function in gastric cancer remains unclear with evidence suggesting that it is to be involved in tumor progression and metastasis. The study was to assess the clinicopathologic relevance and prognostic value of MOR1 expression in gastric cancer.

METHODS

Real-time quantitative RT-PCR and immunohistochemical staining were used to detect MOR1 expression in primary gastric cancerous surgical specimens and adjacent nontumorous tissues.

RESULTS

High MOR1 expression was detected in cancerous tumor compared with their adjacent nontumorous tissues. In addition, the chi-square test revealed that high MOR1 expression was significantly correlated with depth of invasion (p = 0.006), lymph node metastasis (p = 0.001), distant metastasis (p = 0.017), and TNM staging (p = 0.027). Moreover, Kaplan-Meier analysis revealed a significant association between MOR1 expression and overall survival. High expression of MOR1 was identified as an independent and significant predictor gene of reduced postoperative survival.

CONCLUSION

We conclude that MOR1 expression may be a useful biomarker for better prediction of the clinical outcome and management of gastric cancer patients.

Association of opioid requirement and cancer pain with survival in advanced non-small cell lung cancer

BACKGROUND

Pain is associated with shorter survival in non-small cell lung cancer (NSCLC). Lung cancer cells express opioid receptors. Opioids promote angiogenesis, tumour growth, and metastases, and shorten survival in animal models.

METHODS

We examined retrospectively if long-term opioid requirement, independently of chronic pain, is associated with reduced survival in 209 patients with stage IIIB/IV NSCLC. Opioid doses were converted to average oral morphine equivalents (OME). Patients were stratified by proportion of time they reported severe pain, and required <5 or ≥5 mg day^-1 OME. Effects of pain, opioid requirement, and known prognostic variables on overall survival were analysed.

RESULTS

Severe pain before chemotherapy initiation was associated with shorter survival (hazards ratio 1.39, 95% confidence interval, 1.02-1.87, P=0.035). The magnitude of pain and opioid requirement during first 90 days of chemotherapy were predictive of shorter survival: patients with no/mild pain and requiring <5 mg day^-1 OME had 12 months longer median survival compared with those requiring more opioids, experiencing more pain, or both (18 compared with 4.2-7.7 months, P≤0.002). Survival differences (16 compared with 5.5-7.8 months, P<0.001) were similar when chronic pain and opioid requirement were assessed until death or last follow-up. In multivariable models, opioid requirement and chronic pain remained independent predictors of survival, after adjustment for age, stage, and performance status.

CONCLUSIONS

The severity of chronic cancer-related pain or greater opioid requirement is associated with shorter survival in advanced NSCLC, independently of known prognostic factors. While pain adversely influences prognosis, controlling it with opioids does not improve survival. Prospective studies should determine if pain control using equi-analgesic opioid-sparing approaches can improve outcomes.

Morphine stimulates cancer progression and mast cell activation and impairs survival in transgenic mice with breast cancer

BACKGROUND

Morphine stimulates angiogenesis and cancer progression in mice. We investigated whether morphine influences tumour onset, development, and animal model survival, and whether µ-opioid receptor (MOR), lymphangiogenesis, mast cell activation, and substance P (SP) are associated with the tumour-promoting effects of morphine.

METHODS

Transgenic mice with a rat C3(1) simian virus 40 large tumour antigen fusion gene which demonstrate the developmental spectrum of human infiltrating ductal breast carcinoma were used. Mice were treated at different ages with clinically relevant doses of morphine or phosphate-buffered saline to determine the effect on tumour development and progression, and on mouse survival. Tumours were analysed for MOR, angiogenesis, lymphangiogenesis, SP, and mast cell activation by immunofluorescent- or laser scanning confocal-microscopy. Cytokine and SP levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Morphine did not influence tumour development when given before the onset of tumour appearance, but significantly promoted progression of established tumours, and reduced survival. MOR-immunoreactivity (ir) was observed in larger but not in smaller tumours. Morphine treatment resulted in increased tumour angiogenesis, peri-tumoural lymphangiogenesis, mast cell activation, and higher levels of cytokines and SP in tumours. SP-ir co-localized with mast cells and elsewhere in the tumours.

CONCLUSIONS

Morphine does not affect the onset of tumour development, but it promotes growth of existing tumours, and reduces overall survival in mice. MOR may be associated with morphine-induced cancer progression, resulting in shorter survival. Mast cell activation by morphine may contribute to increased cytokine and SP levels, leading to cancer progression and refractory pain.