A delicate balance: risks vs benefits of opioids in cancer pain

A Randomized, Double-Blind, Placebo-Controlled Trial Protocol Using the Fuzhengxiaoliu Patch for the Management of Primary Liver Cancer Pain

Objective

Chronic pain strongly affects the quality of life of patients with liver cancer pain. Safe and effective management of cancer-related pain is a worldwide challenge. Traditional Chinese medicine (TCM) has rich clinical experience in the treatment of cancer pain. The Fuzhengxiaoliu patch (FZXLP) is a compound TCM with the effects of detoxification and pain relief and has shown great efficacy in the treatment of patients with liver cancer, but high-quality clinical research that provides research-based evidence is lacking. We designed a randomized, double-blind, placebo-controlled trial to explore and evaluate the efficacy of FZXLP for the treatment of liver cancer pain.

Methods

This is a prospective, randomized, double-blind, placebo-controlled trial. The trial will enrol 72 participants with primary liver cancer with cancer pain (damp-heat stagnation and toxin and blood stasis syndrome). The primary objective is to measure the reduction in pain using FZXLP in combination with tegafur, gimeracil and oteracil potassium capsule (S-1) compared to the placebo group with S-1. Pain will be measured by the number of opioids used, Chinese versions of the numerical rating scale (NRS), pain relief rate and number of breakthrough cases of cancer pain (BTcP). The secondary objectives include response evaluation criteria in solid tumors (RECIST), tumor markers, TCM syndrome scores, weight, functional assessment of cancer therapy-hepatobiliary (FACT-Hep) questionnaire scores, and self-rating anxiety scale scores. Adverse events (AEs) will be recorded throughout the study.

Discussion

This study integrated TCM with clinical research to assess the efficacy and safety of the addition of FZXLP in the treatment of primary liver cancer pain.

Trial registration

Chinese clinical trial registry, ChiCTR2300076951, Registered on October 25, 2023. https://www.chictr.org.cn/showproj.html?proj=209608.

Addressing gaps in pain research from an integrated whole person perspective

ABSTRACT

While our understanding of pain is rapidly growing, some areas of pain research are lagging behind. This article discusses two current and inter-related gaps in knowledge that are in need of addressing: first, the connections between "brain" and "body" components of pain; and second, the process of endogenous pain resolution. Historical reasons for these research gaps are discussed and solutions are outlined based on an integrative, whole person research approach. These include comprehensive mapping of the mechanosensory and nociceptive innervation of deep tissues; developing objective, non-invasive measurements to quantify the metabolic, structural and mechanical components of the peripheral tissue environment; integrating our understanding of pain pathophysiology, across whole organs and whole body, as well as across bio-psycho-social domains; and understanding the interplay of nervous system and peripheral tissue mechanisms that promote the endogenous resolution of pain and prevent its acute-to-chronic transition. Current NIH-led efforts in these areas are outlined, including several studies within the NIH HEAL (or Help End Addition Long Term) initiative and the National Center for Complementary and Integrative Health's strategic priorities in whole person research.

Trajectories of Opioid Use Before and After Cancer Diagnosis: A Population-Based Cohort Study

BACKGROUND

Opioid use prior to cancer diagnosis increases the likelihood of long-term use during survivorship, however, patterns of use before and after diagnosis are not understood.

METHODS

We used population-based dispensing data linked with cancer and death notifications to identify two cohorts of adults residing in New South Wales initiating opioids within 24 months prior to a first cancer diagnosed between 2014 and 2016: 'survivors' (alive 24 months following diagnosis) and 'decedents' (died within 24 months). We used group-based trajectory modelling to identify trajectories of monthly opioid dispensings and dispensed oral morphine equivalent milligrams (OMEmg) during the 24 months before/after cancer diagnosis.

RESULTS

There were 21,843 survivors with four prediagnosis opioid dispensing trajectories: infrequent (58% of the cohort), late increasing (26%), moderate (10%), and sustained dispensing (6%). We observed an overall increase in dispensed OMEmg of 83 OMEmg (95% CI: 76-91) during the month of diagnosis, with strong opioid formulations comprising most treatment postdiagnosis. Within each prediagnosis opioid trajectory group, we observed five to six postdiagnosis trajectory groups, including no opioid dispensing. Moderate and sustained prediagnosis groups had large proportions of people continuing or increasing opioid dispensing after diagnosis, while small proportions discontinued opioid treatment. We observed similar trajectories in the decedent cohort.

CONCLUSIONS

There is considerable heterogeneity in opioid use before and after cancer diagnosis. Our findings suggest noncancer factors drive a significant proportion of postdiagnosis opioid use, but use increased significantly from the month of cancer diagnosis and never returned to prediagnosis levels.

Opioid use in cancer patients compared with noncancer pain patients in a veteran population

BACKGROUND

Opioid safety initiatives may secondarily impact opioid prescribing and pain outcomes for cancer care.

METHODS

We reviewed electronic health record data at a tertiary Veterans Affairs system (VA Palo Alto) for all patients from 2015 to 2021. We collected outpatient Schedule II opioid prescriptions data and calculated morphine milligram equivalents (MMEs) using Centers for Disease Control and Prevention conversion formulas. To determine the clinical impact of changes in opioid prescription, we used the highest level of pain reported by each patient on the 0-to-10 Numeric Rating Scale in each year, categorized into mild (0-3), moderate (4-6), and severe (7 and above).

RESULTS

Among 89 569 patients, 9073 had a cancer diagnosis. Cancer patients were almost twice as likely to have an opioid prescription compared with noncancer patients (69.0% vs 36.7%, respectively). The proportion of patients who received an opioid prescription decreased from 27.1% to 18.1% (trend P < .01) in cancer patients and from 17.0% to 10.2% in noncancer patients (trend P < .01). Cancer and noncancer patients had similar declines of MMEs per year between 2015 and 2019, but the decline was more rapid for cancer patients (1462.5 to 946.4, 35.3%) compared with noncancer patients (1315.6 to 927.7, 29.5%) from 2019 to 2021. During the study period, the proportion of noncancer patients who experienced severe pain was almost unchanged, whereas it increased among cancer patients, reaching a significantly higher rate than among noncancer patients in 2021 (31.9% vs 27.4%, P < .01).

CONCLUSIONS

Our findings suggest potential unintended consequences for cancer care because of efforts to manage opioid-related risks.

Association of Race/Ethnicity, Persistent Poverty, and Opioid Access Among Patients with Gastrointestinal Cancer Near the End of Life

BACKGROUND

Social determinants of health (SDoH) can impact access to healthcare. We sought to assess the association between persistent poverty (PP), race/ethnicity, and opioid access among patients with gastrointestinal cancer near the end-of-life (EOL).

METHODS

SEER-Medicare patients with gastric, liver, pancreatic, biliary, colon, and rectal cancer were identified between 2008 and 2016 near EOL, defined as 30 days before death or hospice enrolment. Data were linked with county-level poverty from the American Community Survey and the US Department of Agriculture (2000-2015). Counties were categorized as never high-poverty (NHP), intermittent high-poverty (IHP) and persistent poverty (PP). Trends in opioid prescription fills and daily dosages (morphine milligram equivalents per day) were examined.

RESULTS

Among 48,631 Medicare beneficiaries (liver: n = 6551, 13.5%; pancreas: n = 13,559, 27.9%; gastric: n = 5486, 1.3%; colorectal: n = 23,035, 47.4%), there was a steady decrease in opioid prescriptions near EOL. Black, Asian, Hispanic, and other racial groups had markedly decreased odds of filling an opioid prescription near EOL (Black: OR 0.84, 95% CI 0.79-0.90; Asian: OR 0.86, 95% CI 0.79-0.94; Hispanic: OR 0.90, 95% CI 0.84-0.95; Other: OR 0.83, 95% CI 0.74-0.93; all p < 0.05). Even after filling an opioid prescription, this subset of patients received lower daily doses versus White patients (Black: -16.5 percentage points, 95% CI -21.2 to -11.6; Asian: -11.9 percentage points, 95% CI -18.5 to -4.9; Hispanic: -19.1 percentage points, 95%CI -23.5 to -14.6; all p < 0.05). The disparity in opioid access and average daily doses among was attenuated in IHP/PP areas for Asian, Hispanic, and other racial groups, yet exacerbated among Black patients.

CONCLUSIONS

Race/ethnicity-based disparities in EOL pain management persist with SDoH-based variations in EOL opioid use. In particular, PP impacted EOL opioid access and utilization.

Barriers to Adequate Pain Control and Opioid Use Among Cancer Survivors: Implications for Nursing Practice

BACKGROUND

Cancer survivors can experience long-term negative effects from cancer and its treatment. Pain is one of the most common and distressing symptoms that cancer survivors experience. Opioids are often prescribed for pain; however, cancer survivors who have completed active treatment may have unique challenges with regard to pain management.

OBJECTIVE

The aim of this study was to explore barriers to pain management and perceptions of opioid use among cancer survivors.

METHODS

This research was an exploratory pilot study using in-depth qualitative interviews with adult cancer survivors who were recruited from community-based survivorship organizations. Data were analyzed using applied thematic analysis techniques.

RESULTS

Participants (n = 25) were mostly women (96%), diagnosed with breast cancer (88%) and stages I to III disease (84%), with a mean age of 56.2 years. Three themes on barriers to adequate pain control emerged: (1) taking just enough to take the edge off: self-medicating behaviors and nonadherence to prescribed regimen; (2) lack of insurance coverage and costly alternative pain treatment options; and (3) chronicity of cancer-related pain not adequately addressed and often mismanaged.

CONCLUSIONS

Discussions with cancer survivors unveiled personal accounts of unmanaged pain resulting from limited pain management/opioid education, fear of opioid addiction, negative perceptions/experiences with opioids, lack of insurance coverage for alternative pain therapies, and regulatory policies limiting access to opioids.

IMPLICATIONS FOR PRACTICE

There is a clear need for improved access to multimodal pain management options and nonopioid alternatives for cancer survivors. Oncology nurses should endeavor to support policies and procedures aimed at opioid education, training, and legislation.

"I Refused to Get Addicted to Opioids": Exploring Attitudes About Opioid Use Disorder in Patients With Advanced Cancer Pain and Their Support People

Patients with advanced cancer are commonly prescribed opioids, yet patient attitudes about opioid risks (eg, opioid use disorder, or OUD) are understudied. Our objective was to use in-depth qualitative interviews to understand perceptions of opioid prescribing and OUD in patients with advanced, solid-tumor cancers and their support people. We conducted a qualitative study using a rigorous inductive, qualitative descriptive approach to examine attitudes about OUD in patients with advanced cancer (n = 20) and support providers (n = 11). Patients with cancer hold 2 seemingly distinct views: prescription opioids are addictive, yet OUD cannot happen to me or my loved one. Participants described general concerns about the addictive nature of prescription opioids ("My biggest concern… would just be the risk of getting addicted to the medication or even like, overdosing it"), while separating cancer pain management from OUD when considering prescription opioid risks and benefits ("They need to make sure they get the right ones, when they're taking it away from you."). Finally, participants identified personal characteristics and behaviors that they felt were protective against developing OUD (commonly control, willpower, and responsibility). This rigorous qualitative study demonstrates that patients with advanced cancer and their support people simultaneously hold concerns about the addictive nature of prescription opioids, while distancing from perceptions of OUD risks when using opioids for cancer pain management. Given high rates of opioid exposure during advanced cancer treatment, it is important to explore opportunities to promote a balanced understanding of prescription opioid use and OUD risks in this population. PERSPECTIVE: Though prescription opioids carry risk of OUD, there is little data to help guide patients with advanced cancer. Findings suggest that there is a need to develop new, innovative strategies to promote effective pain management and minimize opioid risks in this complex population.

Opioid-prescribing considerations in patients with cancer and substance misuse or substance use disorder: a scoping review protocol

OBJECTIVE

This scoping review aims to describe factors in the existing literature that may inform opioid-prescribing decisions for patients with a past or present history of cancer and past or present substance misuse or substance use disorder.

INTRODUCTION

Opioids and opioid-related decisions are critical components of cancer care. Most individuals with cancer will experience pain during cancer care, and over half of patients will receive an opioid prescription. Opioid-prescribing decisions require weighing the benefits and harms. The presence of substance misuse or substance use disorder may elevate the risk of opioid-related harms, but there is a lack of consensus on managing patients at this intersection.

INCLUSION CRITERIA

This review will consider studies that include adult patients with a past or present history of cancer who also have pain and current or historical substance misuse or substance use disorder. The pain may be cancer-related or non-cancer-related. Studies of patients with all types of cancer will be eligible for inclusion, with the exception of non-melanoma skin cancers. Eligible studies will explore factors that inform opioid-prescribing decisions in this patient population.

METHODS

The review will be conducted according to JBI methodology for scoping reviews. Studies written in English since database inception will be included. The databases to be searched include MEDLINE (Ovid), CINAHL (EBSCO), Embase, APA PsycINFO, and Google Scholar. Eligible studies will undergo data extraction by 2 independent reviewers using a data extraction tool created by the authors. A narrative summary will describe study characteristics, population details, and strategies used to determine appropriate pain management in the patient population.

The other side of the coin: Positive view on the role of opioids in cancer

Opioids have been used for medicinal purposes as an analgesic and recreational purposes as a euphorigenic throughout human history. Cancer patients are often treated with different doses of opioids concurrently with anti-cancer drugs for pain relief without exhibiting excessive adverse effects. The intersection of the biology of pain, opioid therapy, and disease progression represents the crux of the matters and is of potentially great importance in cancer care. For more than 20 years, multiple investigations have focused on the stimulatory effects of opioids on cancer cell growth, while in-depth studies on the inhibitory effects on cancer cell growth development have usually been neglected. This paper reviews the evidence regarding opioid therapies and their anti-cancer effects on various malignancies. Likewise, we have a glimpse into the molecular mechanisms necessary for pinpointing their positive or negative impacts on malignancies to raise awareness and stimulate more excellent dialogue regarding their carcinogenic/anticarcinogenic roles.

Impacts of an Opioid Safety Initiative on US Veterans Undergoing Cancer Treatment

BACKGROUND

There is limited research on how the opioid epidemic and consequent risk reduction policies have affected pain management among cancer patients. The purpose of this study was to analyze how the Opioid Safety Initiative (OSI) implemented at the Veterans Health Administration affected opioid prescribing patterns and opioid-related toxicity.

METHODS

We performed an interrupted time series analysis of 42 064 opioid-naïve patients treated at the Veterans Health Administration for prostate, lung, breast, and colorectal cancer from 2011 to 2016. Segmented regression was used to evaluate the impact of the OSI on the incidence of any new opioid prescriptions, high-risk prescriptions, persistent use, and pain-related emergency department (ED) visits. We compared the cumulative incidence of adverse opioid events including an opioid-related admission or diagnosis of misuse before and after the OSI. All statistical tests were 2-sided.

RESULTS

The incidence of new opioid prescriptions was 26.7% (95% confidence interval [CI] = 25.0% to 28.4%) in 2011 and increased to 50.6% (95% CI = 48.3% to 53.0%) by 2013 before OSI implementation (monthly rate of change: +3.3%, 95% CI = 1.3% to 4.2%, P < .001). After the OSI, there was a decrease in the monthly rate of change for new prescriptions (-3.4%, 95% CI = -3.9 to -2.9%, P < .001). The implementation of the OSI was associated with a decrease in the monthly rate of change of concomitant benzodiazepines and opioid prescriptions (-2.5%, 95% CI = -3.2% to -1.8%, P < .001), no statistically significant change in high-dose opioids (-1.2%, 95% CI = -3.2% to 0.9%, P = .26), a decrease in persistent opioid use (-5.7%, 95% CI = -6.8% to -4.7%, P < .001), and an increase in pain-related ED visits (+3.0%, 95% CI = 1.0% to 5.0%, P = .003). The OSI was associated with a decreased incidence of opioid-related admissions (3-year cumulative incidence: 0.9% [95% CI = 0.7% to 1.0%] vs 0.5% [95% CI = 0.4% to 0.6%], P < .001) and no statistically significant change in the incidence of opioid misuse (3-year cumulative incidence: 1.2% [95% CI = 1.0% to 1.3%] vs 1.2% [95% CI = 1.1% to 1.4%], P = .77).

CONCLUSIONS

The OSI was associated with a relative decline in the rate of new, persistent, and certain high-risk opioid prescribing as well as a slight increase in the rate of pain-related ED visits. Further research on patient-centered outcomes is required to optimize opioid prescribing policies for patients with cancer.

Racial, Ethnic, and Socioeconomic Discrepancies in Opioid Prescriptions Among Older Patients With Cancer

PURPOSE

Minority race and lower socioeconomic status are associated with lower rates of opioid prescription and undertreatment of pain in multiple noncancer healthcare settings. It is not known whether these differences in opioid prescribing exist among patients undergoing cancer treatment.

METHODS AND MATERIALS

This observational cohort study involved 33,872 opioid-naive patients of age > 65 years undergoing definitive cancer treatment. We compared rates of new opioid prescriptions by race or ethnicity and socioeconomic status controlling for differences in baseline patient, cancer, and treatment factors. To evaluate downstream impacts of opioid prescribing and pain management, we also compared rates of persistent opioid use and pain-related emergency department (ED) visits.

RESULTS

Compared with non-Hispanic White patients, the covariate-adjusted odds of receiving an opioid prescription were 24.9% (95% CI, 16.0 to 33.9, P < .001) lower for non-Hispanic Blacks, 115.0% (84.7 to 150.3, P < .001) higher for Asian-Pacific Islanders, and not statistically different for Hispanics (-1.0 to 14.0, P = .06). There was no significant association between race or ethnicity and persistent opioid use or pain-related ED visits. Patients living in a high-poverty area had higher odds (53.9% [25.4 to 88.8, P < .001]) of developing persistent use and having a pain-related ED visit (39.4% [16.4 to 66.9, P < .001]).

CONCLUSION

For older patients with cancer, rates of opioid prescriptions and pain-related outcomes significantly differed by race and area-level poverty. Non-Hispanic Black patients were associated with a significantly decreased likelihood of receiving an opioid prescription. Patients from high-poverty areas were more likely to develop persistent opioid use and have a pain-related ED visit.

Exemptions to state laws regulating opioid prescribing for patients with cancer-related pain: A summary

BACKGROUND

Cancer-related pain is highly prevalent and is commonly treated with prescription opioids. The Centers for Disease Control and Prevention (CDC) now encourages conservative opioid prescribing in recognition of potential opioid-related risks. However, CDC guidelines have been misapplied to patients with cancer. Recent laws at the state level reflect the CDC's guidance by limiting opioid prescribing. It is unclear whether states exempt cancer-related pain, which may affect cancer pain management. Thus, the objective of this study was to summarize current state-level opioid prescribing laws and exemptions for patients with cancer.

METHODS

Two study authors reviewed publicly available state records to identify the most recent opioid prescribing laws and cancer-related exemptions. Documents were required to have the force of law and be enacted at the time of the search (November 2020).

RESULTS

Results indicated that 36 states had enacted formal legislation limiting the duration and/or dosage of opioid prescriptions, and this was largely focused on acute pain and/or initial prescriptions. Of these states, 32 (89%) explicitly exempted patients with cancer-related pain from opioid prescribing laws. Exemptions were broadly applied, with few states providing specific guidance for cancer-related pain prescribing.

CONCLUSIONS

The results of this study indicate that most states recognize the importance of prescription opioids in cancer-related pain management. However, drafting nuanced and clinically relevant opioid legislation is challenging for a heterogenous population. Additionally, current attempts to regulate opioid prescribing by state law may unintentionally undermine patient-centered approaches to pain management. Additional resources are needed to facilitate clarity at the intersection of opioid-related legislation and clinical management for cancer-related pain.

LAY SUMMARY

In this review of state-level legislation, current limitations on opioid prescribing are summarized and detailed information is provided on exemptions for patients with cancer. The majority of states have enacted specific dosage and/or duration limitations on opioid prescribing while including broad exemptions for cancer-related pain. Cancer-related pain exemptions are important to include, as is consistent with national and professional guidelines (eg, the Centers for Disease Control and Prevention). However, these exemptions may also unintentionally undermine patient-centered approaches to pain management. Additional resources, including specific guidance for patients with cancer, are needed to facilitate clarity at the intersection of opioid-related legislation and clinical pain management. ​.

Exploring Factors Associated With Long-Term Opioid Therapy in Cancer Survivors: An Integrative Review

CONTEXT

The prevalence of chronic pain in cancer survivors is double that of the general U.S.

POPULATION

Opioids have been the foundation of cancer pain management for decades; however, there is a paucity of literature on long-term opioid therapy (LTOT) in cancer survivors. An understanding of factors related to LTOT use in cancer survivors is needed to address chronic pain and balance opioid harms in the expanding population of cancer survivors.

OBJECTIVES

To analyze the research of LTOT utilization and factors associated with persistent opioid use in cancer survivors.

METHODS

A five-stage integrative review process was adapted from Whittemore and Knafl. Data sources searched included Web of Science, PubMed, Embase, Cochrane, and Google Scholar. Quantitative research studies from 2010 to present related to cancer survivors managed on LTOT were included. Editorials, reviews, or abstracts were excluded.

RESULTS

After reviewing 315 articles, 21 articles were included. We found that there were several definitions of LTOT in the reviewed studies, but the duration of opioid use (i.e., more than three months after completion of curative treatment) was the most common. The reviewed literature describes a relationship between LTOT and important biopsychosocial factors (cancer type, socioeconomic factors, and comorbidities).

CONCLUSION

The studies in this review shed light on the factors associated with LTOT in cancer survivors. LTOT was common in certain populations of cancer survivors and those with a collection of patient-specific characteristics. This review suggests that there is a critical need for specialized research on chronic cancer pain and opioid safety in cancer survivors.

Cancer Patients' Perceived Difficulties Filling Opioid Prescriptions After Receiving Outpatient Supportive Care

CONTEXT

Limited access to opioids for patients with cancer has been reported as a potential unintended consequence of recent regulations restricting opioid use and prescribing practices. To our knowledge, there are a limited number of peer-reviewed studies that evaluate the perceived difficulties of the patients with cancer when filling their opioid prescription. To understand these difficulties, we surveyed patients receiving opioids in our outpatient supportive care center (SCC).

OBJECTIVES

The primary objective of this study was to evaluate cancer patients' perceptions of overall difficulties when filling their opioid prescription. Secondary objectives included determining associations between patient characteristics and difficulty and comparing difficulty between filling opioid and nonopioid prescriptions.

METHODS

Patients with cancer receiving opioids that had been seen two times or more at our SCC were asked to complete a survey. The information collected included patient demographics, clinical characteristics, and patients' experiences filling their opioid prescription.

RESULTS

The patients' median age was 60 years; 54% were female and 69% were white. Forty-four patients (32%) reported that they have experienced difficulty filling their opioid prescription. More than 25% of those 44 patients perceived difficulty from interactions with the pharmacy and/or pharmacist. Forty-six patients (33%) reported more difficulty filling their opioid prescriptions than filling their nonopioid prescriptions.

CONCLUSION

This study provides evidence that patients with cancer visiting our SCC perceived difficulties obtaining their opioid prescriptions. The results suggest that negative interactions with the pharmacy and/or pharmacist contribute to their perceived difficulty. Additional research is needed to further characterize the contributors of the difficulties patients with cancer face in filling their opioid prescriptions.

Risk of Chronic Opioid Use After Radiation for Head and Neck Cancer: A Systematic Review and Meta-Analysis

Purpose

Opioid addiction is a major public health concern. Chronic opioid use (COU) patterns after radiation for head and neck cancer (HNC) remain poorly understood. The aim of this study was to estimate the prevalence of COU and to identify its risk factors in patients with HNC undergoing curative-intent radiation therapy (RT) or chemoradiotherapy (CRT).

Methods and Materials

We performed a systematic review and meta-analysis using the PubMed (Medline), EMBASE, and Cochrane Library databases, queried from dates of inception until January 2020. COU was defined as persistent use of opioids ≥ 3 months after treatment completion. Meta-analyses were performed using random effects models. Heterogeneity was assessed using the I² value.

Results

Seven retrospective studies, reporting on 1841 patients, met the inclusion criteria. Median age was 59.4 (range: 56.0-62.0) years with 1343 (72.9%) men and 498 (27.1%) women. Primary tumor locations included oropharynx (n = 891, 48.4%), oral cavity (n = 533, 29.0%), larynx (n = 93, 5.1%), hypopharynx (n = 32, 1.7%), and nasopharynx (n = 29, 1.6%). Eight hundred fifty-four (46.0%) patients had stage I/II and 952 (50.3%) had stage III-IV disease. Three hundred one (16.3%) patients had RT alone, 738 (40.1%) received CRT, and 594 (32.3%) underwent surgery followed by adjuvant RT/CRT. The proportion of patients with HNC who developed COU post-RT/CRT was 40.7% at 3 months (95% confidence interval [CI]: 22.6%-61.7%; I² = 97.1%) and 15.5% at 6 months (95% CI: 7.3%-29.7%; I² = 94.3%). Oropharyngeal malignancies had the highest rate of COU based on primary tumor location (46.6%; 95% CI: 30.8%-63.1%; P < .0001). High proportions of COU were found in patients with a history of psychiatric disorder(s) (61.7%), former/current alcohol abuse (53.9%), and opioid requirements before radiation treatment (51.6%; P = .035).

Conclusions

A significant proportion of patients who undergo RT for HNC suffer from COU. High-risk factors for COU include an oropharyngeal primary, history of psychiatric disorder, former/current alcohol abuse, and pre-treatment opioid use. New strategies to mitigate COU are needed.

Pain management with opioids in adults

Given the ubiquitous nature of opioids in the treatment of pain, it is an interesting paradox that this class of medications also represents one of the least understood components of clinical pain medicine. For many years, there has been intense interest in the mechanisms of opioid activity, but this has not resulted in a corresponding increase in convincing clinical data. This review focuses primarily on the evidence surrounding the long-term use of opioids in chronic pain, but discussions of this research are often conflated with the very different data governing acute and cancer-related pain, where evidence of efficacy is clearer. It is therefore important to clarify the evidence-based indications for opioid therapy. There remains very little evidence that opioids improve function or quality of life beyond 3 months in people with chronic pain conditions. In all three patient populations, the development of tolerance, dependence, hyperalgesia and withdrawal are key phenomena that affect the patient experience, and in particular the decision to remain on opioids in the long term. This is a common thread that connects the opioid literature in all of these spheres, and justifies the burgeoning interest in these phenomena in the basic science literature. There is an urgent need to address these negative consequences of opioid use, in order to maximize the therapeutic benefit that opioids can offer.