Impact and management of breakthrough pain in cancer

Trajectories and predictors of high-occurrence pain flares in ambulatory cancer patients on opioids

BACKGROUND

Pain flares have a substantive impact on the quality of life and well-being of patients with cancer. We identified longitudinal trajectories (clusters) of cancer pain flares in ambulatory patients and sociodemographic and clinical predictors of these trajectories.

METHODS

In a prospective cohort study using ecological momentary assessment (mEMA), we collected patient-reported daily pain flare ratings data over 5 months and identified predictors and correlates using validated measures.

RESULTS

The mean age of the sample (N = 270) was 60.9 years (SD = 11.2), 64.8% were female, and 32.6% self-identified as African American. Four pain flare clusters were identified. The "high-occurrence" cluster (23% of patients) experienced 5.5 (SD = 5.47) daily flares, whereas low-moderate clusters (77%) reported 2.4 (SD = 2.74) daily flares (P < .000). Those in the high-occurrence cluster reported higher pain scores (P = .000), increased pain-related interference (P = .000), depressive symptoms (P = .023), lower quality of life (P = .001), and reduced pain self-efficacy (P = .006). Notably, 67.2% of those prescribed opioids as needed (PRN only) were in the high-occurrence pain flare cluster, compared with 27.9% with PRN and around-the-clock opioid prescriptions (P = .024). Individual predictors of high-occurrence pain flares were income below $30 000, unemployment, being African American, lower education level, Medicaid insurance, current opioid misuse (COMM), baseline inpatient hospital stay duration, and PRN-only opioid regimen. In the multiple predictor model, lower education level, unemployment, COMM score, extended inpatient duration, and PRN-only opioid regimen remained significant.

CONCLUSION

In ambulatory patients with cancer, high occurrence of pain flares may be mitigated by attention to opioid prescription factors and addressing social determinants of health needs of underserved patients.

A systematic review of qualitative research exploring patient and health professional perspectives of breakthrough cancer pain

PURPOSE

Breakthrough cancer pain (BtCP) is a prevalent health issue which is difficult to manage. A plethora of quantitative research in this area exists. There is a paucity of research on the perspectives of health professionals and patients surrounding domains impacting effective treatment, including definitions of BtCP, treatment, and education opportunities. This review aims to identify and synthesize the extent of qualitative research exploring health professional and patient perspectives of BtCP.

METHODS

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach was undertaken. The approach was registered with Prospero. MEDLINE, EMBASE, and Web of Science were searched for peer-reviewed literature published any date prior to May 19, 2022. Eligible sources must have considered health professional and/or patient perspectives of BtCP. A narrative synthesis approach was utilized.

RESULTS

Three sources met the review criteria. One source explored nurse perspectives, while two sources explored patient perspectives. Study quality was moderate to high. Overlapping themes across the three studies included communication, defining BtCP, impact of BtCP, management of BtCP, perceptions of BtCP, analgesia and pain relief, and training and professional development.

CONCLUSION

Given limited research investigating clinician and patient perspectives of BtCP, a rich understanding informed by exploratory qualitative methods around identification, best management strategies, professional development, and factors promoting and inhibiting best practice remains unclear. Further qualitative inquiry is warranted, and it is expected such research will inform BtCP clinical guidelines.

Differences and Similarities in Spontaneous Activity Between Animal Models of Cancer-Induced Pain and Neuropathic Pain

Background

Clinical data on cancer-induced pain (CIP) demonstrate widespread changes in sensory function. It is characterized in humans not only by stimulus-invoked pain, but also by spontaneous pain. In our previous studies in an animal model of CIP, we observed changes in intrinsic membrane properties and excitability of dorsal root ganglion (DRG) sensory neurons corresponding to mechanical allodynia and hyperalgesia, of which abnormal activities of Aβ-fiber sensory neurons are consistent in a rat model of peripheral neuropathic pain (NEP).

Objective

To investigate whether there are related peripheral neural mechanisms between the CIP and NEP models of spontaneous pain, we compared the electrophysiological properties of DRG sensory neurons at 2–3 weeks after CIP and NEP model induction.

Methods

CIP models were induced with metastasis tumour-1 rat breast cancer cells implanted into the distal epiphysis of the femur. NEP models were induced with a polyethylene cuff implanted around the sciatic nerve. Spontaneous pain in animals is measured by spontaneous foot lifting (SFL). After measurement of SFL, the animals were prepared for electrophysiological recordings of spontaneous activity (SA) in DRG neurons in vivo.

Results

Our data showed that SFL and SA occurred in both models. The proportion of SFL and SA of C-fiber sensory neurons in CIP was more significantly increased than in NEP models. There was no difference in duration of SFL and the rate of SA between the two models. The duration of SFL is related to the rate of SA in C-fiber in both models.

Conclusion

Thus, SFL may result from SA activity in C-fiber neurons in CIP and NEP rats. The differences and similarities in spontaneous pain between CIP and NEP rats is related to the proportion and rate of SA in C-fibers, respectively.

Diagnosis and Treatment of Five Pain-Related Conditions in Urban China: A Population-Based Cross-Sectional National Health and Wellness Survey

Background

While there is an extensive body of research regarding pain and its treatment in developed countries, little research on this topic has been performed in developing countries. This study aimed to investigate the diagnosis, treatment, and treatment satisfaction in individuals with pain in urban China using real-world data.

Methods

All respondents from the 2013, 2015, and 2017 China National Health and Wellness Survey were included in the analysis and were classified into diagnosed and undiagnosed groups according to their self-reported physician diagnosis or experience in the past month. The following five categories of pain were analysed: headache, cancer-associated pain, musculoskeletal pain, neuropathic pain, and fibromyalgia. Rates for diagnosis, treatment, and satisfaction with medication were calculated overall and for each pain type.

Results

A total of 3802 respondents reported experience of at least one type of pain in the past month. Among those, 61.2% were diagnosed with a pain-related condition, the majority of which (84.0%) were receiving treatment. For diagnosed respondents taking over-the-counter and/or prescription medication, 70.3% were satisfied with their treatment. Comparing between pain types, the diagnosis rates for cancer-associated pain (32.7%) and fibromyalgia (22.8%) were relatively low, whereas respondents with musculoskeletal pain has the highest diagnosis rate (61.1%). Respondents with cancer-associated pain had the lowest satisfaction (30.0%) with over-the-counter and prescription medication, while respondents with headache (76.2%) had the highest satisfaction rate with such medications.

Conclusion

Our study highlights the importance of raising awareness for pain management as well as education and training for healthcare providers and patients.

The nonreceptor protein tyrosine kinase Src participates in every step of cancer-induced bone pain

Cancer-induced bone pain (CIBP) is a refractory form of pain that has a high incidence in advanced tumors. Src protein tyrosine kinase is mainly composed of six domains, with two states of automatic inhibition and activation. The modular domain allows Src to conveniently regulate by and communicate with a variety of proteins, directly or indirectly participate in each step of the CIBP process. Src is beneficial to the growth and proliferation of tumor cells, and it can promote the metastases of primary tumors to bone. In the microenvironment of bone metastasis, it mainly mediates bone resorption, activates related peripheral receptors to participate in the formation of pain signals, and may promote the generation of pathological sensory nerve fibers. In the process of pain signal transmission, it mainly mediates NMDAR and central glial cells to regulate pain signal intensity and central sensitization, but it is not limited to these two aspects. Both basic experimentation and clinical research have shown encouraging potential, providing new ideas and inspiration for the prevention and treatment of CIBP.

Cultural adaptation and psychometric validation of the Portuguese breakthrough pain assessment tool with cancer patients

OBJECTIVES

Breakthrough cancer pain (BTcP) is a transient exacerbation of pain that occurs over persistent, stable, and adequately controlled cancer background pain. It is prevalent and bears severe consequences to patients' quality-of-life. The effective management of BTcP depends on fast and reliable (re)assessment. The Breakthrough pain Assessment Tool (BAT) is one of the most concise and reliable self-report instruments adapted to clinical contexts so far, showing good psychometric qualities in the United Kingdom, the Netherlands, and South Korea. As to promote the effective management of BTcP in Portuguese-speaking communities this study, first aimed to culturally adapt and validate the Portuguese version of the BAT (BAT-Pt). Second, and most importantly, it sought to provide novel evidence on its criterion validity by investigating its association with measures of psychological distress, which has not been yet investigated.

METHODS

The BAT was translated into European Portuguese, using the back-translation method, and culturally adapted. Its psychometric properties (factor structure, internal consistency, construct and criterion validity) were analyzed in a cross-sectional multicenter study, with a sample of 65 cancer patients (49.2% women) recruited from eight hospitals in mainland Portugal (a priori power analysis determined a minimum sample of 50). Health professionals collected patients' clinical information, assessed their functional disability (ECOG Performance Status) and the adequacy of pain control. In addition to the Portuguese version of the BAT (BAT_Pt), patients completed the Portuguese versions of the Brief Pain Inventory, the Hospital Anxiety and Depression Scale, a Distress Thermometer and answered questions about the adequacy of pain control.

RESULTS

The BAT-Pt was very well accepted by experts and patients. As hypothesized, a Principal Axis Factor Analysis revealed two underlying factors accounting for 55.2% of the variance: (1) Pain Severity and Impact of BTcP and (2) Duration of BTcP and Medication Inefficacy. Two items (on episode frequency and medication efficacy) were analyzed separately given their lower/cross loadings. The BAT-Pt showed good internal consistency overall (α=0.79) and for each sub-scale, namely, Pain Severity and Impact of BTcP (n=5 items; α=0.86) and Duration of BTcP and Medication Inefficacy (n=2 items; r_sb=0.62). The BAT-Pt showed good convergent validity, being moderately to strongly associated with overall pain severity and interference (0.46<r<0.77, p<0.001). It also showed good concurrent validity by being associated not only with physical outcomes - such as functional disability (r=0.40, p<0.001) and patient- and physician-determined adequacy of BTcP control (|0.25<r_pb<0.63|, p _s <0.05) - but also, with distress (0.33<r<0.46, p _s <0.001), anxiety (0.28<r<0.44, p _s <0.05) and depression (r=0.47, p<0.001).

CONCLUSIONS

The BAT-Pt is a reliable and valid measure of breakthrough pain in Portuguese cancer patients and it is strongly associated to physical and psychological outcomes. This study confirms and extends the psychometric validation of the BAT to a new cultural context, promoting its diffusion and use by researchers and clinicians in Portuguese-speaking communities. The BAT-Pt may be an invaluable tool for daily clinical practice by tapping multiple aspects of BTcP experiences that are associated to patients' physical and psychological outcomes.

Pain: Persistent postsurgery and bone cancer-related pain

The generation of neuropathic pain is a complex dynamic process. Factors involved include one or more dysregulated sensory neural pathways; dysregulated activity of specific neurotransmitters, synapses, receptors and cognitive and emotional neural circuits; and the balance between degenerative and regenerative neural events. Risk factors include age, sex, cognition, emotions, genetic polymorphism, previous or ongoing chronic pain conditions and the use of certain drugs. Intense pain experienced before, during and after surgery is a risk factor for the development of central sensitization with consequent persistent postsurgery neuropathic pain. Blockade of N-methyl-D-aspartate receptors with appropriate drugs during and immediately after surgery may prevent persistent postsurgical pain. Most cancers, but particularly malignant metastases in bone, can induce persistent pain. Local factors including direct damage to sensory nerve fibres, infiltration of nerve roots by cancer cells and algogenic biological agents within the microenvironment of the tumour bring about central sensitization of dorsal horn neurons, characterized by neurochemical reorganization with persistent cancer pain. In this article, the clinical features, pathogenesis and principles of management of persistent postsurgery pain and cancer pain are briefly discussed.

Practice Patterns in Distinguishing Between Background Pain and Breakthrough Pain During Patient Education: a Korean Physician Survey

This study sought to explore the association between physician practice patterns and patient education, with a focus on breakthrough cancer pain (BTcP). A nationwide online survey was conducted by 92 Korean physicians. Thirteen questions on Korean physician's assessment, prescription, patient education practices, and knowledge regarding BTcP were administered. Based on their responses, physicians were divided using two methods: (1) by their patient education practices, where the "education group" always explained the distinction between background pain and BTcP and the "less education group" which explained it less frequently; and (2) by their definition of BTcP, as occurring "after control of background pain" or "regardless of background pain." We compared practice patterns using Fisher's exact test or Student's t test and performed multiple logistic regression analysis. The "education group" (65 physicians, 70.7 %) was more likely than the "less education group" to assess BTcP meticulously (odds ratio [OR] 17.13, 95 % confidence interval [CI] 4.98-58.94), prepare rescue medications in advance (OR 3.67, 95 % CI 1.36-9.90), and give explicit instructions regarding medications (OR 36.68, 95 % CI 5.63-239.15). Physicians who defined BTcP as occurring "after control of background pain" were more likely to explain how to take rescue medication (P < 0.05) than physicians who defined BTcP as occurring "regardless of background pain." Korean physicians' BTcP practice patterns may be affected by whether they consistently educate patients on the distinction between background pain and BTcP, regardless of their knowledge of the definition of BTcP.

Validation of the Korean Version of the Breakthrough Pain Assessment Tool in Cancer Patients

CONTEXT

Breakthrough cancer pain has not been properly evaluated and treated because there are relatively few available measurements. The Breakthrough Pain Assessment Tool (BAT) is currently recognized as a brief, multidimensional, and reliable measurement.

OBJECTIVES

The objective of this study was to validate the Korean version of the BAT (BAT-K) in adult cancer patients.

METHODS

We conducted a forward-backward translation and cross-cultural equivalence test. The psychometric properties with 120 cancer patients were assessed using factor analysis, reliability, and validity.

RESULTS

The Korean translation was well accepted by participants. Factor analysis revealed the presence of two underlying factors: frequency/severity and duration/medication efficacy. Cronbach alpha coefficient was 0.743. Severity, distress, and disruption of normal life showed strong reliability. The intraclass correlation for the test-retest reliability was 0.782 (95% confidence interval 0.694-0.854). The BAT-K had significant correlations with the Brief Pain Inventory, Pain Management Index, and Eastern Cooperative Oncology Group performance status (all P values < 0.05).

CONCLUSION

The BAT-K is a valid and reliable measurement of breakthrough cancer pain in Korean cancer patients.

Using education and support strategies to improve the way nurses assess regular and transient pain – A quality improvement study of three hospitals

Background and aims

Systematic and regular pain assessment has been shown to improve pain management. Well-functioning pain assessments require using strategies informed by well-established theory. This study evaluates documented pain assessments reported in medical records and by patients, including reassessment using a Numeric Rating Scale (NRS) after patients receive rescue medication.

Methods

Documentation surveys (DS) and patient surveys (PS) were performed at baseline (BL), after six months, and after 12 months in 44 in-patient wards at the three hospitals in Östergötland County, Sweden. Nurses and nurse assistants received training on pain assessment and support. The Knowledge to Action Framework guided the implementation of new routines.

Results

According to DS pain assessment using NRS, pain assessment increased significantly: from 7% at baseline to 36% at 12 months (p < 0.001). For PS, corresponding numbers were 33% and 50% (p < 0.001). According to the PS, the proportion of patients who received rescue medication and who had been reassessed increased from 73% to 86% (p = 0.003). The use of NRS to document pain assessment after patients received rescue medication increased significantly (4% vs. 17%; p < 0.001).

Conclusions

After implementing education and support strategies, systematic pain assessment increased, an encouraging finding considering the complex contexts of in-patient facilities. However, the achieved assessment levels and especially reassessments related to rescue medication were clinically unsatisfactory. Future studies should include nursing staff and physicians and increase interactivity such as providing online education support. A discrepancy between documented and reported reassessment in association with given rescue medication might indicate that nurses need better ways to provide pain relief.

Implications

The fairly low level of patient-reported pain via NRS and documented use of NRS before and 12 months after the educational programme stresses the need for education on pain management in nursing education. Implementations differing from traditional educational attempts such as interactive implementations might complement educational programmes given at the work place. Standardized routines for pain management that include the possibility for nurses to deliver pain medication within well-defined margins might improve pain management and increase the use of pain assessments. Further research is needed that examines the large discrepancy between patient-reported pain management and documentation in the medical recording system of transient pain.

Association of Performance Status and Pain in Metastatic Bone Pain Management in the Spanish Clinical Setting

INTRODUCTION

Bone metastasis is the most common cause of cancer-related pain, and metastatic bone pain (MBP) is not only severe but also progressive in many patients. The aim of this study was to investigate the association between pain management and performance status in patients with metastatic bone cancer in the Spanish clinical setting.

METHODS

A 3-month follow-up prospective, epidemiologic, multicenter study was conducted in 579 patients to assess the evolution of their performance, the impact of pain control on sleep and functionality, and the degree of pain control according to analgesic treatment.

RESULTS

In patients with MBP, Eastern Cooperative Oncology Group (ECOG) status (1.5 ± 0.7-1.3 ± 0.7 and 1.3 ± 0.8; p < 0.001) and pain (6.5 ± 1.4-2.8 ± 1.9 and 2.1 ± 1.9; p < 0.001) improved significantly from baseline to months 1 and 3, as did functionality and sleep, after a treatment change consisting of increasing the administration of opioids. Evolution of ECOG and pain were closely related. ECOG and pain outcomes were significantly more favorable in patients treated with opioids versus non-opioid treatment, and in patients who did not need rescue medication versus those who did.

CONCLUSIONS

MBP is currently poorly managed in Spain. ECOG improvement is closely and directly related to pain management in MBP. Opioid treatment and a lack of requirements for rescue medication are associated with better ECOG and pain outcomes in MBP patients.

FUNDING

Mundipharma Pharmaceuticals S.L.

What to Do, and What Not to Do, When Diagnosing and Treating Breakthrough Cancer Pain (BTcP): Expert Opinion

Clinical management of breakthrough cancer pain (BTcP) is still not satisfactory despite the availability of effective pharmacological agents. This is in part linked to the lack of clarity regarding certain essential aspects of BTcP, including terminology, definition, epidemiology and assessment. Other barriers to effective management include a widespread prejudice among doctors and patients concerning the use of opioids, and inadequate assessment of pain severity, resulting in the prescription of ineffective drugs or doses. This review presents an overview of the appropriate and inappropriate actions to take in the diagnosis and treatment of BTcP, as determined by a panel of experts in the field. The ultimate aim is to provide a practical contribution to the unresolved issues in the management of BTcP. Five ‘things to do’ and five ‘things not to do’ in the diagnosis and treatment of BTcP are proposed, and evidence supporting said recommendations are described. It is the duty of all healthcare workers involved in managing cancer patients to be mindful of the possibility of BTcP occurrence and not to underestimate its severity. It is vital that all the necessary steps are carried out to establish an accurate and timely diagnosis, principally by establishing effective communication with the patient, the main information source. It is crucial that BTcP is treated with an effective pharmacological regimen and drug(s), dose and administration route prescribed are designed to suit the particular type of pain and importantly the individual needs of the patient.

Prospective Observational Study of Patient-Controlled Intrathecal Analgesia: Impact on Cancer-Associated Symptoms, Breakthrough Pain Control, and Patient Satisfaction

BACKGROUND AND OBJECTIVES

Although data exist for the efficacy of intrathecal therapy (ITT), there are no prospective data on patient-controlled intrathecal analgesia (PCIA) in refractory cancer pain. This study examines the effect of PCIA on cancer symptom scores, patient satisfaction, and analgesic efficacy with an emphasis on breakthrough pain (BTP).

METHODS

Ninety-eight patients with refractory cancer pain prospectively completed questionnaires including the MD Anderson Symptom Inventory and a BTP survey before and after the implantation of an intrathecal pump.

RESULTS

Fifty-eight patients were included in the study group. Average "worst" pain scores decreased from 8.32 (SD, 1.73) pre-ITT to 4.98 (SD, 2.92) post-ITT, P < 0.001. Severe pain (numerical rating score ≥7) decreased from 84.2% to 35.2% (P < 0.001). Mean daily morphine equivalent dosing decreased from 805.3 mg/d to 128.2 mg/d, with 65.5% of patients discontinuing all nonintrathecal opioids. The mean MD Anderson Symptom Inventory symptom severity score decreased from 4.98 to 3.72 (P < 0.0001), and the symptom interference score from 6.53 to 4.37 (P < 0.001). Pain reduction was 46.8% with pre-ITT breakthrough medications and 65.2% with PCIA (P < 0.001). Median time to onset was 30 minutes with pre-ITT breakthrough medications and 10 minutes with PCIA (P < 0.001). Patient-controlled intrathecal analgesia, compared with conventional BTP medications, was "a lot better" in 60.7% and "a little better" in 28.6%. Overall pain control satisfaction was also improved, with 78.2% "a lot better" and 10.9% "I have no pain."

CONCLUSIONS

In patients with poorly controlled cancer pain, PCIA is associated with improved pain control, improved cancer-related symptoms, and high satisfaction. Compared with conventional BTP regimens, PCIA provides superior analgesia and a 3-fold faster onset of action.

Cancer pain physiology

Mechanisms of inflammatory and neuropathic pains have been elucidated and translated to patient care by the use of animal models of these pain states. Cancer pain has lagged behind since early animal models of cancer-induced bone pain were based on the systemic injection of carcinoma cells. This precluded systematic investigation of specific neuronal and pharmacological alterations that occur in cancer-induced bone pain. In 1999, Schwei et al. described a murine model of cancer-induced bone pain that paralleled the clinical condition in terms of pain development and bone destruction, confined to the mouse femur. This model prompted related approaches, and we can now state that cancer pain may include elements of inflammatory and neuropathic pains but also unique changes in sensory processing. Cancer-induced bone pain results in progressive bone destruction, elevated osteoclast activity and distinctive nocifensive behaviours (indicating the triad of ongoing, spontaneous and movement-induced hyperalgesia). In addition, cancer cells induce an inflammatory infiltrate and release growth factors, cytokines, interleukins, chemokines, prostanoids and endothelins, resulting in a reduction of pH to below 5 and direct deformation of primary afferents within bone. These peripheral changes, in turn, drive hypersensitivity of spinal cord sensory neurons, many of which project to the parts of the brain involved in the emotional response to pain. Within the spinal cord, a unique neuronal function reorganization within segments of the dorsal horn of the spinal cord receiving nociceptive input from the bone are discussed. Changes in certain neurotransmitters implicated in brain modulation of spinal function are also altered with implications for the affective components of cancer pain. Treatments are described in terms of mechanistic insights and in the case of opioids, which modulate pain transmission at spinal and supraspinal sites, their use can be compromised by opioid-induced hyperalgesia. We discuss evidence for how this comes about and how it may be treated.

Breakthrough pain in elderly patients with cancer: treatment options

The prevalence of pain is high in the elderly and increases with the occurrence of cancer. Pain treatment is challenging because of age-related factors such as co-morbidities, and over half of the patients with cancer pain experience transient exacerbation of pain that is known as breakthrough pain (BTP). As with background pain, BTP should be properly assessed before being treated. The first step to be taken is optimizing around-the-clock analgesia with expert titration of the painkiller. Rescue medication should then be provided as per the requested need, while at the same time preventing identified potential precipitating factors. In the elderly, starting treatment with a lower dose of analgesics may be justified because of age-related physiological changes such as decreased hepatic and renal function. Whenever possible, oral medication should be provided prior to a painful maneuver. In the case of unpredictable BTP, immediate rescue medication is mandatory and the subcutaneous route is preferred unless patient-controlled analgesia via continuous drug infusion is available. Recently, transmucosal preparations have appeared in the medical armamentarium but it is not yet known whether they represent a truly efficient alternative, although their rapid onset of activity is already well recognized. Adjuvant analgesics, topical analgesics, anesthetic techniques and interventional techniques are all valid methods to help in the difficult management of pain and BTP in elderly patients with cancer. However, none has reached a satisfying scientific level of evidence as to nowadays make the development of undisputed best practice guidelines possible. Further research is therefore on the agenda.

Pharmacokinetic comparison study of a combination containing 500 mg of Naproxen and 20 mg of Esomeprazole: a randomized, single-dose, 2-way crossover, open-label study in healthy Korean men

PURPOSE

Nonsteroidal anti-inflammatory drugs have been used for analgesic, anti-inflammatory, and antithrombotic effects, but they carry a risk of major gastrointestinal damage. This risk can be greatly reduced by the coadministration of inhibitors of gastric acid secretion, such as proton pump inhibitors. This study was performed for the subsequent marketing of a combination drug that contained 500 mg of naproxen and 20 mg of esomeprazole in Korea. We evaluated the comparative bioavailability and tolerability of the test and reference formulations in healthy men.

METHODS

A total of 60 healthy men were enrolled in this single-dose, randomized, open-label, 2-period, 2-sequence, crossover study. During each period, men received a combination of 500 mg of naproxen and 20 mg of esomeprazole for test or reference, and between each period, there was a 1-week washout period. Blood samples were obtained 21 times throughout each period before dosing and 0.17, 0.33, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 8, 10, 12, 24, 48, and 72 hours after oral administration. Plasma concentrations were determined using LC-MS/MS. The pharmacokinetic parameters, including Cmax, AUC0-t, AUC0-∞, and Tmax, were measured, and all treatment-emergent adverse events and their associations with the study medications were recorded throughout the entire study.

FINDINGS

A total of 59 men completed the study. No significant differences were found in the prevalence of AEs between the 2 formulations. In addition, there were no serious or unexpected AEs during the study. Both formulations had very similar Cmax, AUC, and t½ values, but the Tmax of naproxen appeared earlier in the test formulation than in the reference formulation and that of esomeprazole appeared later in the test formulation than in the reference formulation.

IMPLICATIONS

This study suggests that the test and reference formulations of a combination of 500 mg of naproxen and 20 mg of esomeprazole are bioequivalent in the extent of absorption and peak concentration. We anticipate that the test formulation will treat those who need relief from pain and inflammation and will decrease the risk of developing gastric ulcers. cris.nih.go.kr identifier: KCT0001117.

Patient Satisfaction with Fentanyl Sublingual Spray in Opioid-Tolerant Patients with Breakthrough Cancer Pain

OBJECTIVES

Breakthrough cancer pain (BTCP) is associated with decreased satisfaction with around-the-clock opioid therapy. This analysis examined patient satisfaction with fentanyl sublingual spray for BTCP during the open-label titration period of a randomized, placebo-controlled study.

METHODS

Opioid-tolerant patients with 1 to 4 daily BTCP episodes were included. During a 26-day, open-label titration phase, a successful dose (100 to 1600 mcg) of fentanyl sublingual spray was established that provided effective analgesia for 2 consecutive BTCP episodes with tolerable side effects. The Treatment Satisfaction Questionnaire for Medication (TSQM) was administered at baseline to assess satisfaction with previous BTCP medication and at the end of the titration to assess satisfaction with fentanyl sublingual spray.

RESULTS

Of 130 enrolled patients, 115 (88.5%) had a TSQM measure at baseline and at the end of their titration period. Scores on all 4 TSQM domains increased from baseline to end of the titration, with mean (standard error [SE]) improvements of 22.3 (2.3) for effectiveness, 7.7 (3.2) for side effects, 6.8 (2.2) for convenience, and 12.9 (2.8) for global satisfaction (P < 0.05 for all). Satisfaction with symptom relief (26.1% to 77.4%) and onset of action (21.7% to 82.6%) also improved from baseline to end of titration. At least one adverse event (AE) was reported by 78 patients (60.0%). The most common AEs considered possibly or probably related to study medication were dizziness, somnolence, and nausea (n = 10 [7.7%] each).

DISCUSSION

These data indicate markedly improved satisfaction among patients receiving fentanyl sublingual spray relative to previous BTCP medications.

Breakthrough pain in patients with controlled or uncontrolled basal pain: an observational study

Recently, there has been debate regarding the definition of ‘breakthrough pain’ and the patients to whom the term applies, with suggestions made to broaden the definition to include both patients with uncontrolled and controlled baseline pain, rather than only patients with controlled pain. To contribute to this discussion, the authors assessed the occurrence and characteristics of breakthrough pain among patients with controlled and uncontrolled baseline pain.

BACKGROUND:

Breakthrough pain (BTP) is traditionally defined as a pain exacerbation in patients with chronic controlled pain. However, this definition has recently been challenged.

OBJECTIVES:

To evaluate the prevalence of unsatisfactory control in patients with chronic cancer pain, and investigate the frequency and intensity of BTP episodes.

METHODS:

A total of 665 patients with chronic cancer pain attending 21 pain therapy units in Italy were evaluated for baseline pain intensity and number of BTP episodes over a 30-day period. All patients started, continued or modified treatment for BTP at enrollment, according to medical judgment.

RESULTS:

The number of BTP events was higher in patients with uncontrolled baseline pain, although the intensity and duration of episodes were similar. In patients with uncontrolled baseline pain, the number of events decreased with time and reached values comparable with those reported in patients with controlled pain. Both the intensity of the pain and the duration of the BTP events exhibited similar values in the two groups at all time points, following increased monitoring and the prescription of analgesic medication.

CONCLUSION:

Patients with uncontrolled baseline pain experienced BTP flares with higher frequency, but similar intensity and duration with respect to patients with controlled pain at baseline. Notably, a close follow-up and adequate management of the BTP episodes led to an improvement of BTP in the observed patients.

A randomized, placebo-controlled study of a new sublingual formulation of fentanyl citrate (fentanyl ethypharm) for breakthrough pain in opioid-treated patients with cancer

BACKGROUND

Oromucosal fentanyl is currently used for the treatment of breakthrough pain (BTP) in opioid-treated cancer patients. Ethypharm developed a sublingual formulation of fentanyl suprabioavailable to oral transmucosal fentanyl citrate with a higher early systemic exposure and a shorter Tmax.

OBJECTIVES

This study evaluated the efficacy and safety profile of fentanyl Ethypharm (FE) in relieving BTP in opioid-treated cancer patients.

METHODS

Opioid-treated adult cancer patients, experiencing 1 to 4 episodes of BTP per day, were included in the study. After an open-label titration period to identify an optimal dose that would provide adequate pain relief for 2 consecutive episodes of BTP with an acceptable level of adverse events, patients were randomly assigned to a double-blind, placebo-controlled, crossover period with 1 of 13 prespecified sequences of 9 tablets (6 tablets of FE of the dose identified during the open-label titration and 3 placebo). Pain intensity and pain relief were recorded at 3, 6, 10, 15, 30, and 60 minutes after study drug administration. Adverse events were recorded. The primary end point was the sum of pain intensity differences (SPID) at 30 minutes.

RESULTS

The distribution of optimal dosages of FE was as follows: 133 µg, 35.9%; 267 µg, 30.8%; 400 µg, 14.1%; 533 µg, 12.8%; and 800 μg, 6.4%. In the modified intention-to-treat population (n = 73), FE significantly improved mean (SE) SPID compared with placebo at 30 minutes (75.0 [49.8] vs 52.5 [52.8]; P < 0.0001). FE significantly improved SPID, pain intensity difference, and pain relief compared with placebo from 6 to 60 minutes' postadministration. Patients with BTP who received placebo required the use of rescue medication more often than those treated with FE (38.4% vs 17.5%; P < 0.0001). A significant improvement in pain scores (>33% and >50% reductions) was also reported for BTP treated with FE. Pain scores for patients with BTP with a neuropathic component (13 patients) were lower with FE than for those receiving placebo, but the difference was not significant. AEs were of mild or moderate severity and typical of opioid drugs.

CONCLUSIONS

This newly developed galenic formulation with a higher early systemic exposure and a shorter Tmax compared with oral transmucosal fentanyl citrate makes FE a particularly suitable formulation for the management of BTP in opioid-treated cancer patients due to the very rapid onset of action. FE provided significant improvement in pain intensity of BTP compared with placebo as early as 6 minutes' postadministration with a sustained effect over 60 minutes. FE was well tolerated by patients. ClinicalTrials.gov identifier: NCT 01842893.

Effect of dose escalation with single opioid, fentanyl matrix in patients not controlling cancer pain: a multicenter, prospective, observational study in Korea

Purpose

End-of-dose failure (EOD) is a clinically common observation and many cancer patients increase the frequency of opioid administration. Fentanyl matrix use is known to be effective in patients with chronic cancer pain. To measure the effectiveness of increase in a single dose of fentanyl matrix in patients whose pain was not controlled sufficiently, we perform this study.

Materials and Methods

A multi-center, open-label, prospective, observational study was conducted in 30 hospitals in Korea, between August and December 2008.

Results

A total of 452 patients were enrolled; 404 patients completed the study. The mean pain intensity decreased from 5.27 at the first visit to 3.37 at the end of the trial. There was a significant difference in pain intensity (p < 0.001) between the first and last visits. The percentage of pain intensity difference was 30.1%. The prevalence of EOD at the first visit was 73% from the 452 enrolled patients. After the use of fentanyl patch, EOD decreased from 73% to 56%. Pain intensity of patients experiencing EOD was 5.64 at the baseline compared to 4.27 in patients without EOD. On final visit, pain intensity in patients with and without EOD was 4.02 and 2.54, respectively. The observed adverse events were mainly nausea, asthenia, constipation and diarrhea.

Conclusion

This study demonstrated that increasing dose of fentanyl patch decreased pain intensity and decreased the rate of patients experiencing EOD. Thus, fentanyl patch may be an effective modality in cancer patients whose pain was previously not controlled sufficiently; the side effects were as could be expected with an opioid.

Prevalence of breakthrough cancer pain: a systematic review and a pooled analysis of published literature

CONTEXT

Despite the large body of literature on breakthrough cancer pain (BTcP), an accurate estimate of BTcP prevalence is still not available.

OBJECTIVES

To provide an estimate of BTcP prevalence and investigate the association between different prevalence rates and possible determinants.

METHODS

We conducted MEDLINE and EMBASE searches for studies published from 1990 to 2012 reporting data on BTcP prevalence in adult cancer populations. Pooled prevalence rates from observational studies with an acceptable methodological quality were computed. The association between BTcP prevalence and possible predictors was investigated using subgroup analyses and meta-regression.

RESULTS

Twenty-seven observational studies were identified. When quality criteria were applied, only 19 studies were included in the pooled analysis. The overall pooled prevalence was 59.2%, with high heterogeneity. The lowest prevalence rates were detected in studies conducted in outpatient clinics (39.9%), and the highest prevalence was reported in studies conducted in hospice (80.5%). The association between BTcP prevalence and other determinants such as publication year, age, gender, metastatic disease prevalence, or baseline pain intensity did not reach statistical significance.

CONCLUSION

In the context of a large between-studies heterogeneity, more than one in two patients with cancer pain also experiences BTcP, with some variability according to clinical and organizational variables.

European Oncology Nursing Society breakthrough cancer pain guidelines

PURPOSE

The overall aim of the project was to update and inform nurses of current best practice based on previously published literature to enable nurses to assess and manage breakthrough cancer pain (BTCP) and thereby to provide optimal management of BTCP.

METHODS

The EONS started a project in 2010 by recruiting a working group and a multidisciplinary advisory board to develop guidelines with the purpose of helping oncology nurses understand and recognise BTCP.

RESULTS

This paper presents and overview of the guideline. Key recommendations include; using an algorithm for assessment of BTCP, individualise treatment interventions, optimization of analgesia and reassessment of outcomes of interventions.

CONCLUSIONS

By implementing the EONS guidelines nurses will utilise the latest available knowledge in clinical practice and the understanding and management of BTCP will improve assessment and overall management of breakthrough pain in cancer patients.

Beyond the traditional definition of breakthrough pain: an observational study

INTRODUCTION

Breakthrough pain (BTP) is traditionally defined as a transitory pain flare in opioid-treated patients with chronic background pain. This definition has, however, been challenged in recent years. This study aimed to analyze BTP prevalence in different pain conditions.

METHODS

This was a prospective, non-interventional, observational study conducted from June to September 2011 in two Italian pain treatment reference centres. Consecutive patients aged >18 years with oncological or non-oncological pain were eligible for this study; background pain was acute/ subacute (<3 months) or chronic (>3 months). The characteristics of pain were evaluated by means of a structured interview by physicians, and patients were asked to complete a dedicated clinical study form. The following outcomes were assessed: chronic pain duration (in patients with chronic pain), BTP prevalence, and number and severity of daily BTP episodes. All outcomes were assessed in four populations of patients with: (a) chronic oncological pain; (b) chronic non-oncological pain; (c) non-chronic oncological pain; (d) non-chronic non-oncological pain. The correlation between BTP and gender was also investigated.

RESULTS

Of 1,270 patients with chronic pain, 1,086 had non-oncological pain (85.5%). Most patients (68.6%) with non-oncological pain were female (P = 0.001). Pain duration was significantly longer in non-oncological pain versus oncological pain groups (P = 0.002). BTP prevalence was lower in non-oncological patients (P < 0.001). No differences were reported in terms of number and severity of daily BTP episodes. BTP was more frequent in females with non-oncological pain (P = 0.04). Females had a significantly higher pain severity (P = 0.02) than males.

CONCLUSION

BTP is frequently reported in patients who do not have BTP according to the traditional definition. BTP frequency and severity is similar in oncological and non-oncological pain.

A new rat model of bone cancer pain produced by rat breast cancer cells implantation of the shaft of femur at the third trochanter level

Bone cancer pain remains one of the most challenging cancer pains to fully control. In order to clarify bone cancer pain mechanisms and examine treatments, animal models mimicking the human condition are required. In our model of Walker 256 tumor cells implantation of the shaft of femur at the third trochanter level, the anatomical structure is relatively simple and the drilled hole is vertical and in the cortical bone only 1-2 mm in depth without injury of the distal femur. Pain behaviors and tumor growth were observed for 21 days. And neurochemical changes were further investigated in this model. The results showed that cancer-bearing rats demonstrated a decreased limb use score from day 14, an increased spontaneous flinching and guarding times from day 7 and a decreased withdrawal threshold from day 6. The tumor infiltration of bone was monitored by MRI and further verified by histological examination. C-fos and the capsaicin receptor (TRPV1) positive neurons were more expressed in cancer-bearing rats and the substance P expression has no difference, suggesting that neurons were activated in the model. Our animal model demonstrated time-dependent tumor growth and pain behaviors and will be a novel animal model of bone cancer pain in the future.

Breakthrough cancer pain - still a challenge

Breakthrough cancer pain is defined as transient pain exacerbation in patients with stable and controlled basal pain. Although variable, the prevalence of breakthrough cancer pain is high (33%–95%). According to the American Pain Foundation, breakthrough pain is observed in 50%–90% of all hospitalized cancer patients, in 89% of all patients admitted to homes for the elderly and terminal-patient care centers, and in 35% of all ambulatory care cancer patients. The management of breakthrough cancer pain should involve an interdisciplinary and multimodal approach. The introduction of new fentanyl formulations has represented a great advance and has notably improved treatment. Among these, the pectin-based intranasal formulation adjusts very well to the profile of breakthrough pain attacks, is effective, has a good toxicity profile, and allows for convenient dosing – affording rapid and effective analgesia with the added advantage of being easily administered by caregivers when patients are unable to collaborate.

A review of the pharmacokinetic profile of transmucosal fentanyl formulations

BACKGROUND AND OBJECTIVES

Breakthrough pain (BTP) is a transitory flare of moderate-to-severe pain that occurs in patients with stable, controlled persistent pain. Management of BTP episodes is difficult because frequency, time-to-peak intensity, and duration of episodes vary both within and between individuals. Formulations of fentanyl that use a buccal, sublingual, or nasal transmucosal route of administration have been developed for the treatment of BTP in opioid-tolerant patients with cancer. These formulations allow rapid passage into the bloodstream and avoid first-pass metabolism and, therefore, are more likely to match the time-course of BTP episodes than are oral formulations. The purposes of this analysis were to identify and review published data describing the pharmacokinetic properties of rapid-onset fentanyl formulations and to evaluate these properties in view of the temporal dynamic characteristics of BTP in order to help guide medical practice.

METHODS

Relevant publications were searched in the PubMed database from 1998. The plasma drug concentration-time profile of each formulation obtained from the identified studies was adjusted to a consistent scale for comparison.

RESULTS

The data revealed that the various transmucosal formulations resulted in three typical plasma fentanyl concentration profiles: (1) type 1: a very rapid rise and short duration; (2) type 2: a rapid increase and sustained intensity; and (3) type 3: a slower onset and longer duration.

CONCLUSIONS

Given the substantial variability of BTP episodes experienced by patients, these pharmacokinetic differences may provide useful information for a physician who is selecting a rapid-onset opioid medication for a patient.

Breakthrough pain in patients referred to pain clinics: the Italian pain network retrospective study

INTRODUCTION

Despite breakthrough pain (BTP) being one of the most severe forms of pain, there are no definitive data on its prevalence.

METHODS

The authors performed a retrospective survey of the prevalence of BTP in consecutive patients in four Italian pain clinics, subsequent to application of an Italian law mandating detailed clinical records on pain characteristics, treatment, and results. Mean pain intensity was assessed with a numerical rating scale from 0 to 10.

RESULTS

The authors analyzed records of 1,401 patients (58% women, 33.1% patients with cancer). Transient episodes of severe pain or BTP were referred by 790 patients (56.4%), including 58.2% of the men (342 of 588) and 55.1% of the women (448 of 813). Among the 464 patients with cancer, 70.3% reported daily exacerbation of pain. The mean BTP intensity was 8.31 ± 1.58 and 31.1% of patients reported experiencing three episodes per day.

CONCLUSION

Despite some limitations of the study, the authors show that transient episodes of severe pain or BTP are significantly present both in cancer and other diseases, and that many patients are not yet receiving appropriate opioid therapy. The authors need validated tools at international level for the diagnosis and treatment of BTP in patients with cancer and for transitory and patients with severe non-cancer pain. A survey at national level is needed to estimate the prevalence of BTP in different settings, to plan specific medical education.

Cancer Pain Management and Bone Metastases: An Update for the Clinician

Breast cancer patients with bone metastases often suffer from cancer pain. In general, cancer pain treatment is far from being optimal for many patients. To date, morphine remains the gold standard as first-line therapy, but other pure μ agonists such as hydromorphone, fentanyl, or oxycodone can be considered. Transdermal opioids are an important option if the oral route is impossible. Due to its complex pharmacology, methadone should be restricted to patients with difficult pain syndromes. The availability of a fixed combination of oxycodone and naloxone is a promising development for the reduction of opioid induced constipation. Especially bone metastases often result in breakthrough pain episodes. Thus, the provision of an on-demand opioid (e.g., immediate-release morphine or rapid-onset fentanyl) in addition to the baseline (regular) opioid therapy (e.g., sustained-release morphine tablets) is mandatory. Recently, rapid onset fentanyls (buccal or nasal) have been strongly recommended for breakthrough cancer pain due to their fast onset and their shorter duration of action. If available, metamizole is an alternative non-steroid-anti-inflammatory-drug. The indication for bisphosphonates should always be checked early in the disease. In advanced cancer stages, glucocorticoids are an important treatment option. If bone metastases lead to neuropathic pain, coanalgetics (e.g., pregabalin) should be initiated. In localized bone pain, radiotherapy is the gold standard for pain reduction in addition to pharmacologic pain management. In diffuse bone pain radionuclids (such as samarium) can be beneficial. Invasive measures (e.g., neuroaxial blockage) are rarely necessary but are an important option if patients with cancer pain syndromes are refractory to pharmacologic management and radiotherapy as described above. Clinical guidelines agree that cancer pain management in incurable cancer is best provided as part of a multiprofessional palliative care approach and all other domains of suffering (psychosocial, spiritual, and existential) need to be carefully addressed («total pain»).

Is morphine still the best reference opioid?

SUMMARY Cancer and noncancer pain can usually be managed according to the WHO analgesic ladder and, in many countries, morphine remains the first-line opioid of choice for chronic severe pain. There have been many advances in the use of opioids for moderate-to-severe pain control in recent years. Consequently, the position of morphine as the gold standard became gradually more questioned, mostly because of serious adverse effects and the availability of different opioids and new formulations. The place of morphine as the first-line option is based on reasons of familiarity, availability or cost rather than medical advantages. In recent years, a number of systematic reviews failed to demonstrate superiority of morphine over other opioids in terms of efficacy or tolerability. Moreover, some strong opioids have shown improved tolerability or convenience. Currently, morphine might still be considered as a reference drug for equivalent dosing, but not for strategic healthcare decisions, as it has not demonstrated clinical or pharmacological superiority over other opioids. Therefore, there is a lack of evidence to sustain the role of morphine as the gold standard in the treatment of chronic severe pain.

Patient-controlled intrathecal analgesia for the management of breakthrough cancer pain: a retrospective review and commentary

OBJECTIVE

  Intrathecal therapy (ITT) via an implanted pump has become an accepted practice for the treatment of refractory cancer pain by infusing opioids and adjuncts directly to the neuraxis. Until recently, only a programmed basal rate of infusion could be delivered, and therefore, breakthrough pain required ongoing use of oral or transmucosal opioids. Recently, an implanted pump manufacturer has introduced a handheld device to bolus additional medication for breakthrough pain. We hypothesize that patient-controlled intrathecal analgesia (PCIA) for the treatment of breakthrough cancer pain reduces the need for breakthrough opioids and improves the patient perception of pain.

METHODS

  A retrospective chart review was done on all patients who underwent ITT for cancer pain between January 2009 and February 2011. Clinical outcomes of interest were reduction in nonintrathecal opioid use and reduction in numerical rating score (NRS) for pain. The data was collected prior to ITT and at a 4-6 week postimplant visit.

RESULTS

  After initiation of ITT with PCIA, 50% of patients had discontinued all nonintrathecal opioids at follow-up, and 46% of the patients on breakthrough medications no longer required their use. At follow-up, there was a significant reduction in total nonintrathecal opioid use, with an average of 796 mg pre-ITT vs 64 mg post-ITT of daily oral morphine equivalent dosing (P = <0.001). There was a significant difference between mean NRS pain score at follow-up-6.5 vs 3.1 pre-ITT (P<0.001). 65% of patients reported their pain as severe (NRS of 7 or greater) prior to ITT; this decreased to 3% at follow-up.

CONCLUSIONS

  In patients with refractory cancer pain, intrathecal drug therapy with PCIA is associated with improved pain reporting, reduced nonintrathecal around-the-clock, and breakthrough opioid requirements.

Sublingual fentanyl orally disintegrating tablet in daily practice: efficacy, safety and tolerability in patients with breakthrough cancer pain

BACKGROUND AND OBJECTIVES

Breakthrough cancer pain (BTcP) affects more than half of patients with cancer pain and has severe detrimental impacts on quality of life (QoL). This study evaluated the efficacy, QoL impact and safety of sublingual fentanyl orally disintegrating tablet (sublingual fentanyl ODT), for the treatment of BTcP in a clinical setting.

RESEARCH DESIGN AND METHODS

This was a prospective, multi-center phase IV study. Opioid-tolerant adult patients with BTcP received sublingual fentanyl ODT in the course of routine clinical practice, and completed questionnaires over a 28-day observation period. Efficacy was assessed using measures of maximum BTcP intensity and the times to first effect and maximum effect of sublingual fentanyl ODT. Changes in QoL were evaluated using the modified pain disability index (mPDI) and the hospital anxiety and depression scale (HADS). Adverse events were recorded throughout.

RESULTS

Of 217 enrolled patients, 181 (83.4%) completed the observation period. During the study, 3163 episodes were treated with a mean dose of 401.4 μg per episode. The study recorded a significant improvement in maximum BTcP intensity with sublingual fentanyl ODT, compared with baseline (p < 0.0001). Patients reported experiencing the first effects of the study drug within 5 minutes of administration in 67.7% of episodes, and maximum effect within 30 minutes in 63.2% of episodes. mPDI and HADS scores significantly improved during the observation period (p < 0.0001). Sublingual fentanyl ODT was well-tolerated, with 12 patients (5.5%) experiencing ≥1 study drug-related adverse event. Study limitations include a modest size and duration, and the single-arm design.

CONCLUSIONS

Under the conditions of a phase IV study, sublingual fentanyl ODT was effective and well-tolerated for the treatment of BTcP in opioid-tolerant cancer patients. Study treatment was associated with significant improvements in BTcP intensity and QoL scores, and patients reported rapid onset of action in the majority of episodes.

Opioids for the management of breakthrough cancer pain in adults: a systematic review undertaken as part of an EPCRC opioid guidelines project

The usual management of cancer related breakthrough pain is with supplemental doses of analgesics (commonly opioids) at a dose proportional to the total around-the-clock opioid dose. The aim of this review, undertaken as part of a European Palliative Care Research Collaborative (EPCRC) project, to update the EAPC guidelines on opioid analgesics in cancer pain was to determine the evidence for the utility of opioids in the management of breakthrough pain in patients with cancer. Randomized controlled trials of opioids used as rescue medication were identified using electronic search strategies. Outcome measures sought were reduction in pain intensity measured by an appropriate scale, adverse effects, attrition, and patient satisfaction. The date of the final search was 31 July 2009. Eight studies (790 patients) met the inclusion criteria. Most studies investigated rescue medication delivery via the buccal or nasal transmucosal routes. Intravenous morphine has been compared with the transmucosal route and the two found to be effective. The oral route has not been formally tested although found to be an inferior comparator in one study. Most studies showed no meaningful relationship between the effective dose of transmucosal opioid and the around-the-clock scheduled medication or the previous rescue medication, although one study found a fixed proportion of either intravenous morphine or transmucosal fentanyl to be efficacious.

Treatment of cancer pain

In patients with active cancer, the management of chronic pain is an essential element in a comprehensive strategy for palliative care. This strategy emphasises multidimensional assessment and the coordinated use of treatments that together mitigate suffering and provide support to the patient and family. This review describes this framework, an approach to pain assessment, and widely accepted techniques to optimise the safety and effectiveness of opioid drugs and other treatments. The advances of recent decades suggest a future that includes increased evidence-based targeting of specific analgesic interventions within an individualised plan of care that is appropriate throughout the course of illness.

Integrated strategies for the successful management of breakthrough cancer pain

PURPOSE OF REVIEW

To highlight the significant impact breakthrough cancer pain (BTcP) can have on patients' quality of life and to discuss potential management strategies that could improve pain control in clinical practice as well as effective strategies to manage risk.

RECENT FINDINGS

BTcP can place a significant physical, psychological and economic burden on patients. Despite advances in the management of cancer pain, through the application of modern, evidence-based, multimodality management and the availability of new treatment options, recent European surveys have indicated that the diagnosis and treatment of BTcP is still suboptimal. A general lack of consensus on its definition alongside poor recognition and inadequate assessment may often lead to undertreatment and poor patient outcomes. Fentanyl preparations that have been developed and licensed specifically for the treatment of BTcP have been shown to work more rapidly and be preferred by patients to traditional rescue medication, such as normal-release oral opioids.

SUMMARY

Optimizing the management of BTcP requires an integrated approach, including independent assessment and better use of available treatments while taking into consideration risk management strategies, which will ultimately lead to improved outcomes and quality of life for patients.

Spinal activation of delta opioid receptors alleviates cancer-related bone pain

Over the past few years, significant progress has been made in cancer therapy. Indeed, the lifespan of cancer patients has significantly increased. Although patients live longer, cancer-related pain remains a daily problem affecting their quality of life, especially when metastases reach the bone. In patients coping with cancer-induced bone pain, morphine and NSAIDs, often used in combination with other medications, are the most commonly used drugs to alleviate pain. However, these drugs have dose-limiting side effects. Morphine and other routinely used opioids are mu opioid receptor (MOPR) agonists. The MOPR is responsible for most opioid-related adverse effects. In the present study, we revealed potent analgesic effects of an intrathecally-administered selective delta opioid receptor (DOPR) agonist, deltorphin II, in a recently developed rat bone cancer model. Indeed, we found that deltorphin II dose-dependently reversed mechanical allodynia 14 days post-surgery in this cancer pain model, which is based on the implantation of mammary MRMT-1 cells in the femur. This effect was DOPR-mediated as it was completely blocked by naltrindole, a selective DOPR antagonist. Using the complete Freund's adjuvant model of inflammatory pain, we further demonstrated that deltorphin II was equipotent at alleviating inflammatory and cancer pain (i.e. similar ED50 values). Altogether, the present results show, for the first time, that activation of spinal DOPRs causes significant analgesia at doses sufficient to reduce inflammatory pain in a rat bone cancer pain model. Our results further suggest that DOPR represents a potential target for the development of novel analgesic therapies to be used in the treatment of cancer-related pain.

Intra- and interindividual variabilities in the pharmacokinetics of fentanyl buccal soluble film in healthy subjects: a cross-study analysis

BACKGROUND AND OBJECTIVE

Breakthrough pain describes transient exacerbations of pain that occur in cancer patients with adequately controlled background pain. Transmucosal fentanyl administration produces rapid-onset and short-duration analgesia that is effective for treating patients with breakthrough pain. Although a significant amount of research has been devoted to the study of speed of analgesia onset of transmucosal fentanyl products, few data exist on their variability in absorption, particularly within the same individual, despite the importance of this characteristic to the dose-to-dose reliability of their analgesic effect. This cross-study analysis aimed to evaluate the intra- and interindividual pharmacokinetic differences of fentanyl administered via fentanyl buccal soluble film in healthy subjects.

METHODS

Data were evaluated from 24 subjects in two pharmacokinetic studies of fentanyl administered via fentanyl buccal soluble film (Breakyl®/Onsolis™; BEMA® [BioErodible MucoAdhesive] technology). In one study, 12 healthy subjects received 600 μg doses of fentanyl as single film on two separate occasions; in the second study, 12 different healthy subjects received 800 μg doses of fentanyl on two separate occasions, one as a single 800 μg film and the other as four 200 μg films.

RESULTS

The analysis showed a minimal intraindividual variability and a relatively higher interindividual variability in pharmacokinetic parameters (i.e. maximum plasma concentration, area under the plasma concentration-time curve from time zero to infinity). The coefficient of variation for intraindividual exposure to fentanyl variability was 7-10%, and for interindividual variability was 23-39%.

CONCLUSION

The minimal intraindividual variability in fentanyl absorption from the buccal soluble film demonstrates a predictable dose-to-dose exposure, which is a very desirable attribute for a medicine that is intended to treat breakthrough cancer pain, suggesting that this product would be expected to produce consistent effects in clinical practice. The greater interindividual variability highlights the need for individual titration of this product (as occurs with similar transmucosal fentanyl products), and for the availability of an adequately wide dose range.

Fentanyl pectin nasal spray: in breakthrough pain in opioid-tolerant adults with cancer

Fentanyl pectin nasal spray (PecFent®) uses a novel pectin-based delivery system that turns from an aqueous solution into a gel when applied to mucosal surfaces. Fentanyl is absorbed in a controlled manner from the pectin gel formed in the nasal cavity, and has a rapid onset of pain relief and duration of action that matches the time course of a typical episode of breakthrough pain in cancer (BTPc). Relative to administration as oral transmucosal fentanyl, fentanyl administered as fentanyl pectin nasal spray is more rapidly absorbed, reaches higher maximum plasma concentrations and has greater bioavailability. In the treatment of BTPc in two randomized, double-blind, crossover trials in opioid-tolerant adults, fentanyl pectin nasal spray (100-800 μg titrated doses) was significantly more effective than placebo in reducing pain intensity and provided a significantly faster onset of pain relief than oral immediate-release morphine. During long-term treatment of BTPc episodes, fentanyl pectin nasal spray consistently provided effective pain relief in an open-label, 16-week trial. Most patients were satisfied or very satisfied with the ease of use and convenience of the nasal spray. Fentanyl pectin nasal spray 100-800 μg was generally well tolerated and was not associated with nasal tolerability problems.

[Experiences of cancer patients with breakthrough pain and pharmacological treatments]

BACKGROUND

of cancer patients receiving palliative care, 80% suffer from cancer pain, and again 80% of these patients report breakthrough pain. This study explores the patients' perception of breakthrough pain, their experiences with existing therapeutic regimens and their expectations regarding an ideal breakthrough pain medication.

METHOD

from November 2008 to February 2010 two German palliative care units recruited 80 in- or outpatient cancer patients who completed a standardized questionnaire on breakthrough pain characteristics, analgesic medication, attitudes towards new treatment approaches for breakthrough pain, and experiences with alternative routes of drug administration as part of the "European Survey of Oncology Patients' Experience of Breakthrough Pain".

RESULTS

the study participants suffered from 1-12 episodes of either incident (47.5%) or spontaneous pain (37.5%) per day which were perceived as "severe" in 71% of all cases. These exacerbations highly interfered with the patients' general activity, mood, walking ability, and normal work. Overall, 64% of the patients reported alleviation from pharmacological (26%) and non-pharmacological (73%) interventions. Subcutaneous (40%) and oral (39%) routes were used frequently; intranasal (1.25%) and intrapulmonary (1.25%) routes were used rarely. Only 64% of all participants stated an overall satisfaction with their breakthrough analgesia.

CONCLUSION

the diagnosis and treatment of breakthrough pain seems to be conducted in a suboptimal manner, and standard recommendations on breakthrough pain relief are not implemented consistently. Possible causes of pain should be taken into account as well as multi-professional treatment interventions and alternative routes of administration of fast onset, effective drugs should be considered.

Treatment strategies to overcome end-of-dose failure with oral and transdermal opioids

Extended-release oral and transdermal opioids are increasingly being used for the management of chronic pain. Although the dosing intervals for these products were established through controlled clinical trials, expanded use of extended-release and transdermal dosage forms has resulted in awareness that a significant number of patients with chronic pain experience loss of baseline pain control prior to the next scheduled dose. End-of-dose failure (EDF) is the term used to describe this type of pain manifestation. By recognizing potential causes of EDF, strategies may be developed to overcome its occurrence to improve patients' pain control.

Bone cancer pain

In the United States, cancer is the second most common cause of death and it is expected that about 562,340 Americans will have died of cancer in 2009. Bone cancer pain is common in patients with advanced breast, prostate, and lung cancer as these tumors have a remarkable affinity to metastasize to bone. Once tumors metastasize to bone, they are a major cause of morbidity and mortality as the tumor induces significant skeletal remodeling, fractures, pain, and anemia. Currently, the factors that drive cancer pain are poorly understood. However, several recently introduced models of bone cancer pain, which closely mirror the human condition, are providing insight into the mechanisms that drive bone cancer pain and guide the development of mechanism-based therapies to treat the cancer pain. Several of these mechanism-based therapies have now entered human clinical trials. If successful, these therapies have the potential to significantly enlarge the repertoire of modalities that can be used to treat bone cancer pain and improve the quality of life, functional status, and survival of patients with bone cancer.