Cancer breakthrough pain characteristics and responses to treatment at a VA medical center

Breast cancer-induced bone remodeling, skeletal pain, and sprouting of sensory nerve fibers

Breast cancer metastasis to bone is frequently accompanied by pain. What remains unclear is why this pain tends to become more severe and difficult to control with disease progression. Here we test the hypothesis that with disease progression, sensory nerve fibers that innervate the breast cancer bearing bone undergo a pathological sprouting and reorganization, which in other nonmalignant pathologies has been shown to generate and maintain chronic pain. Injection of human breast cancer cells (MDA-MB-231-BO) into the femoral intramedullary space of female athymic nude mice induces sprouting of calcitonin gene-related peptide (CGRP(+)) sensory nerve fibers. Nearly all CGRP(+) nerve fibers that undergo sprouting also coexpress tropomyosin receptor kinase A (TrkA(+)) and growth-associated protein-43 (GAP43(+)). This ectopic sprouting occurs in periosteal sensory nerve fibers that are in close proximity to breast cancer cells, tumor-associated stromal cells, and remodeled cortical bone. Therapeutic treatment with an antibody that sequesters nerve growth factor (NGF), administered when the pain and bone remodeling were first observed, blocks this ectopic sprouting and attenuates cancer pain. The present data suggest that the breast cancer cells and tumor-associated stromal cells express and release NGF, which drives bone pain and the pathological reorganization of nearby CGRP(+)/TrkA(+)/GAP43(+) sensory nerve fibers.

PERSPECTIVE

Therapies that block breast cancer pain by reducing the tumor-induced pathological sprouting and reorganization of sensory nerve fibers may provide insight into the evolving mechanisms that drive breast cancer pain and lead to more effective therapies for attenuating this chronic pain state.

Long-term dosing, safety, and tolerability of fentanyl buccal tablet in the management of noncancer-related breakthrough pain in opioid-tolerant patients

OBJECTIVE

To evaluate the long-term dosing, safety, and tolerability of fentanyl buccal tablet (FBT) in a large cohort of opioid-tolerant patients with chronic noncancer pain and breakthrough pain (BTP).

DESIGN

Combined analysis of three double-blind, placebo-controlled, and two open-label studies.

RESULTS

Of 1160 patients who received ≥1 dose of FBT, 83% achieved a successful dose, ranging from 100 to 800 μg, mostly at 600 or 800 μg. Not all of the patients included in this analysis were enrolled in long-term studies and 156 (13%) patients were still receiving ongoing treatment when their study site closed. Median treatment duration was 106.0 days. The mean FBT dose in the post-titration population (n = 946) increased from 2108 to 3132 μg/day, with ≥1 FBT dose increase in 27% of patients; most dose increases occurred during the first 6 months. The FBT daily dose as a proportion of the daily opioid dose remained fairly stable (59-65%) throughout the treatment period. Overall, 925 (80%) enrolled patients had ≥1 adverse event (AE). The most frequent AEs were nausea (21% of patients), vomiting (11%), dizziness (10%), and headache (10%). Common AEs generally occurred within 7 days of starting treatment and lasted for ≤2 days. Serious AEs occurred in 136 (12%) patients and included six deaths (none related to FBT) and 11 instances of opioid overdose (all with satisfactory resolution). AE-related discontinuations occurred in 163 (14%) patients and were similar to the common AEs.

CONCLUSIONS

Despite the limitations, including the controlled clinical setting, this pooled analysis of several clinical studies provides valuable information for the long-term management of BTP with FBT. Patients require regular evaluation and, when necessary, adjustment of opioid medications to maintain adequate pain control. FBT was generally safe and well tolerated in this setting.

Long-term effectiveness and tolerability of sublingual fentanyl orally disintegrating tablet for the treatment of breakthrough cancer pain

BACKGROUND AND OBJECTIVES

Breakthrough cancer pain (BTcP) is a transient exacerbation of cancer pain in patients with otherwise stable, persistent background pain. This study evaluated the long-term effectiveness and tolerability of sublingual fentanyl orally disintegrating tablet (sublingual fentanyl ODT), for the treatment of BTcP in opioid-tolerant patients with cancer.

RESEARCH DESIGN AND METHODS

This was a non-randomized, open-label, multi-center, Phase III study conducted in opioid-tolerant patients (aged ≥17 years) with BTcP. The study comprised a 2-week titration phase, followed by a maintenance phase of up to 12 months. Patients self-administered sublingual fentanyl ODT for episodes of BTcP. Effectiveness was assessed using patients' global evaluation of medication (PGEM), the brief pain inventory (BPI) and the depression, anxiety and positive outlook scale (DAPOS). Adverse events were recorded throughout.

CLINICAL TRIAL REGISTRATION

NCT00263575 (http://www.clinicaltrials.gov/).

RESULTS

Of 139 recruited patients, 69% identified an effective dose of sublingual fentanyl ODT (a dosage that successfully treated all episodes of BTcP over two consecutive days) and entered the maintenance phase, during which they were treated for a median of 149.0 days (mean dose 507.5 µg). The study recorded a significant increase in reported satisfaction with pain medication at the 6-month and end-of-study visits, compared to screening (p ≤ 0.01). Evaluation of quality of life using BPI and DAPOS identified no deterioration in scores and significant improvements in certain parameters (p < 0.05). Sublingual fentanyl ODT was well tolerated, with no study drug-related deaths, and 49 patients (35.3%) experiencing ≥1 study drug-related adverse event. The most common of these included nausea (8.6%), constipation (5.8%) and somnolence (5.8%). There was no evidence of sublingual mucosal irritation due to the study medication. The pattern of adverse events was similar to that previously observed with transmucosal fentanyl.

CONCLUSIONS

Sublingual fentanyl ODT was effective and well tolerated for the long-term treatment of BTcP in opioid-tolerant cancer patients. There was an increase in satisfaction with pain medication during the study, and sublingual fentanyl ODT showed an acceptable safety profile over 12 months of treatment.

Cancer breakthrough pain in the presence of cancer-related chronic pain: fact versus perceptions of health-care providers and patients

Cancer breakthrough pain is a flare in pain that "breaks through" well-controlled persistent cancer pain. Although the condition is highly prevalent, the concept of cancer breakthrough pain is not well understood and is therefore underdiagnosed and undertreated. The purpose of this review is to examine the roles the health-care practitioner and patient/family caregiver play in the undertreatment of breakthrough pain. A lack of technical knowledge about pain management and pain assessment, attitudes about opioid addiction, and regulatory guidelines influence the manner in which opioids are prescribed. Patients harbor a variety of fears and misconceptions, such as opioid addiction, tolerance, side effects, and the meaning of pain, which can create a barrier to effective communication with their health-care provider regarding their cancer pain management and specifically their breakthrough pain. Identifying these issues gives health-care professionals and patients an opportunity to develop strategies that can improve the treatment of cancer breakthrough pain.

The efficacy and safety of fentanyl buccal tablet compared with immediate-release oxycodone for the management of breakthrough pain in opioid-tolerant patients with chronic pain

BACKGROUND

Current clinical guidelines have identified the need for studies comparing the effect of different short-acting or rapid-onset opioids for the treatment of breakthrough pain (BTP). In this study we evaluated the efficacy and safety of treatment with fentanyl buccal tablet (FBT) in comparison with immediate-release oxycodone in alleviating BTP in opioid-tolerant patients with chronic pain.

METHODS

In this cross-over design study, opioid-tolerant patients were randomized to open-label titration with FBT (200, 400, 600, 800 μg) followed by oxycodone (15, 30, 45, 60 mg) or vice versa for the management of BTP. After titration to a successful dose of both study drugs, patients were rerandomized to double-blind treatment for 10 BTP episodes with 1 of the already identified successful doses of study drug followed by cross-over to double-blind treatment for 10 BTP episodes with the other study drug. The primary efficacy measure was the difference in pain intensity (based on an 11-point numerical scale) 15 minutes after administration of study drug (PID(15)). Other efficacy measures included PID at other time points postdose (5 through 60 minutes), the sum of pain intensity differences (SPID) at 30 and 60 minutes postdose, pain relief (5 through 60 minutes), proportion of BTP episodes for which patients experienced meaningful reduction in pain intensity, and patient preference for BTP medication. Adverse events were also recorded.

RESULTS

Of the 323 patients enrolled, 203 achieved a successful dose of both study drugs, 191 completed the titration phase, and 180 completed the double-blind phase. PID(15) was significantly greater after FBT versus oxycodone (mean [SD], 0.82 [1.12] vs. 0.60 [0.88]; 95% confidence interval [CI] = 0.18, 0.29; P < 0.0001). Secondary efficacy measures favored FBT and showed differences versus oxycodone from 5 minutes postdose for PID and 10 minutes postdose for pain relief. SPID(30) and SPID(60) were greater with FBT than with oxycodone (P < 0.0001 for both measures). A ≥33% improvement in pain intensity occurred in a larger proportion of FBT-treated episodes versus oxycodone beginning 15 through 45 minutes postdose (P < 0.05). FBT was preferred by 52% of patients, oxycodone by 33%. Adverse events with both study drugs were generally typical of opioids, and the majority occurred during titration. Two serious adverse events (pneumonia) were reported in 1 patient; both occurrences were considered unrelated to study drug.

CONCLUSION

FBT resulted in more rapid onset of analgesia and was generally well tolerated in comparison with oxycodone for the treatment of BTP in opioid-tolerant patients.

Consistency of efficacy, patient acceptability, and nasal tolerability of fentanyl pectin nasal spray compared with immediate-release morphine sulfate in breakthrough cancer pain

CONTEXT

We recently reported that fentanyl pectin nasal spray (FPNS) provides superior pain relief from breakthrough cancer pain (BTCP) compared with immediate-release morphine sulfate (IRMS), with significant effects by five minutes and clinically meaningful pain relief from 10 minutes postdose.

OBJECTIVES

To report the consistency of efficacy, tolerability, and patient acceptability of FPNS vs. IRMS.

METHODS

Patients (n=110) experiencing one to four BTCP episodes/day while taking ≥60 mg/day oral morphine (or equivalent) for background pain entered a double-blind, double-dummy (DB/DD), multiple-crossover study. Those who completed an open-label titration phase (n=84) continued to a DB/DD phase; 10 episodes were randomly treated with FPNS and overencapsulated placebo or IRMS and nasal spray placebo (five episodes each). Pain intensity (PI) and pain relief scores were assessed. Patient acceptability scores were assessed at 30 and 60 minutes. Safety and tolerability were assessed by adverse events (AEs) and nasal assessments.

RESULTS

Per-episode analysis revealed that FPNS consistently provided relief from pain more rapidly than IRMS; by 10 minutes, there were significant differences in PI difference scores and in the percentages of episodes showing clinically meaningful pain relief (P<0.05). Overall acceptability scores were significantly greater for FPNS than for IRMS at 30 (P<0.01) and 60 (P<0.05) minutes. Patients were "satisfied/very satisfied" with the convenience (79.8%) and ease of use (77.2%) of FPNS. Only 4.7% of patients withdrew from titration because of AEs; no significant nasal effects were reported.

CONCLUSION

This study demonstrates that FPNS is efficacious, well accepted, and well tolerated by patients with BTCP.

Breakthrough pain in cancer patients

Breakthrough pain is a transient exacerbation of pain that occurs either spontaneously or in relation to a specific predictable or unpredictable trigger, despite relatively stable and adequately controlled background pain. A typical episode of breakthrough pain has a fast onset and short duration, yet despite the self-limiting nature of each breakthrough pain, the repeated episodes can have a significant effect on patients' quality of life. Normal-release oral opioids have been the mainstay pharmacological approach for patients who are receiving an around the clock opioid regimen, but the onset and duration of action of oral opioids such as morphine may not be suitable for treating many breakthrough pains. Efforts to provide non-parenteral opioid formulations that could provide more rapid, and more effective, relief of breakthrough pain have led to the development of transmucosal opioid formulations.

Change in cancer pain management in Korea between 2001 and 2006: results of two nationwide surveys

CONTEXT

In Korea, many health care professionals have shown increased concern about the management of cancer pain. Five years after a pain management guideline was distributed to Korean physicians, the Korean Society of Hospice and Palliative Care evaluated the change in cancer pain management. The period evaluated was between 2001 and 2006.

METHODS

We did a prospective, cross-sectional cancer pain survey on the change of the pain prevalence and pain intensity, its impact on daily activities and the adequacy of pain management between 2001 and 2006.

RESULTS

Overall, 7565 patients were enrolled from 72 cancer hospitals in the 2001 cancer pain survey and 7245 patients were enrolled from 63 cancer hospitals in the 2006 cancer pain survey. The overall prevalence of cancer pain and the percentage of patients reporting a negative pain management index were significantly decreased in the 2006 cancer pain survey compared with the 2001 cancer pain survey (44.9% vs. 52.1%, P<0.0001 and 41.6% vs. 45.0%, respectively, P=0.0005). However, in 2006, physicians did not prescribe analgesics to 25.8% of the patients with severe pain and they did not adjust the prescribed analgesics properly in 47.4% of the patients with severe pain.

CONCLUSION

Some improvement in cancer pain management was noted during the five years between 2001 and 2006. However, all of the physicians who care for cancer patients should pay more attention to cancer pain management, and an educational program for cancer pain management should be distributed to all of the physicians who care for cancer patients.

Review article: palliative care in gynecologic oncology

Patients with advanced gynecologic malignancies have a multitude of symptoms; pain, nausea, and vomiting, constipation, anorexia, diarrhea, dyspnea, as well as symptoms resulting from intestinal obstruction, hypercalcemia, ascites, and/or ureteral obstruction. Pain is best addressed through a multimodal approach. The optimum palliative management of end-stage malignant intestinal obstruction remains controversial, with no clear guidelines governing the choice of surgical versus medical management. Patient selection for palliative surgery, therefore, should be highly individualized because only carefully selected candidates may derive real benefit from such surgeries. There remains a real need for more emphasis on palliative care education in training programs.

Pathological sprouting of adult nociceptors in chronic prostate cancer-induced bone pain

Pain frequently accompanies cancer. What remains unclear is why this pain frequently becomes more severe and difficult to control with disease progression. Here we test the hypothesis that with disease progression, sensory nerve fibers that innervate the tumor-bearing tissue undergo a pathological sprouting and reorganization, which in other nonmalignant pathologies has been shown to generate and maintain chronic pain. Injection of canine prostate cancer cells into mouse bone induces a remarkable sprouting of calcitonin gene-related peptide (CGRP(+)) and neurofilament 200 kDa (NF200(+)) sensory nerve fibers. Nearly all sensory nerve fibers that undergo sprouting also coexpress tropomyosin receptor kinase A (TrkA(+)). This ectopic sprouting occurs in sensory nerve fibers that are in close proximity to colonies of prostate cancer cells, tumor-associated stromal cells and newly formed woven bone, which together form sclerotic lesions that closely mirror the osteoblastic bone lesions induced by metastatic prostate tumors in humans. Preventive treatment with an antibody that sequesters nerve growth factor (NGF), administered when the pain and bone remodeling were first observed, blocks this ectopic sprouting and attenuates cancer pain. Interestingly, reverse transcription PCR analysis indicated that the prostate cancer cells themselves do not express detectable levels of mRNA coding for NGF. This suggests that the tumor-associated stromal cells express and release NGF, which drives the pathological reorganization of nearby TrkA(+) sensory nerve fibers. Therapies that prevent this reorganization of sensory nerve fibers may provide insight into the evolving mechanisms that drive cancer pain and lead to more effective control of this chronic pain state.

Treatment of breakthrough pain with fentanyl buccal tablet in opioid-tolerant patients with chronic pain: appropriate patient selection and management

BACKGROUND

Opioids can be a safe and effective option for carefully selected patients with a structured treatment program that includes consistent monitoring. However, the benefits and risks of opioid therapy for patients with chronic pain, and society as a whole, have been sharply debated. A key component of this debate has involved the administration of rapid-onset opioids for the management of breakthrough pain.

OBJECTIVE

Review key aspects of breakthrough pain management with fentanyl buccal tablet, with a focus on minimizing risk to optimize therapeutic outcomes. Recommendations that apply broadly to all rapid-onset opioids are also discussed.

DESIGN

Available fentanyl buccal tablet clinical and post-marketing data were reviewed.

RESULTS

Like other schedule II controlled substances, and because fentanyl buccal tablet is a highly potent opioid, its use is associated with risk of overdose, misuse, and diversion. As with all rapid-onset opioids, particular attention to patient selection and risk assessment is warranted. The inclusion and exclusion criteria in fentanyl buccal tablet clinical studies represent patient selection standards that should be translated to clinical practice, most importantly, that patients are opioid-tolerant before fentanyl buccal tablet initiation. Titration of fentanyl buccal tablet from a low starting dose to a successful dose allows the safe identification of a dose that provides the greatest pain relief without unacceptable adverse events. After initiating fentanyl buccal tablet therapy, all patients should continue to be regularly monitored for response, including analgesia, functioning, tolerability, and aberrant behavior.

CONCLUSIONS

Fentanyl buccal tablet can be an effective and generally safe treatment for breakthrough pain when appropriate patient selection, administration, dosing, and monitoring are applied.

Characterization of cancer-induced bone pain: an exploratory study

PURPOSE

Cancer-induced bone pain (CIBP) is the commonest cause of pain in patients with cancer. Its association with increased morbidity combined with limitations of currently available therapies makes it a clinical challenge. Clinical characterization of this complex pain syndrome is essential in underpinning clinical management and informing future research. The aim of this exploratory study was to characterise CIBP using self-rating scales.

PATIENTS AND METHODS

A cross-sectional survey of patients with CIBP was carried out in a regional oncology centre. Patients described their pain over the preceding 24 h using the McGill Pain Questionnaire, Brief Pain Inventory (BPI), and a breakthrough pain questionnaire. Multiple linear regression analyses were conducted.

RESULTS

Fifty-five patients were recruited. Annoying, gnawing, aching, and nagging were the most commonly used words to describe CIBP. From the BPI, median average pain was 4/10 and worst pain was 7/10 on a 0-10 Numerical Rating Scale. The worst pain score correlated more strongly with BPI interference score (p=0.001). Forty-one patients had breakthrough pain. Patients with breakthrough pain had higher total BPI interference scores than those with no breakthrough pain; median (IQR); 35.0 (2.5-44.7) vs. 18.5 (5.5-26.7), p<0.01. Of the patients, 20/41 (48%) had breakthrough pain of rapid onset (less than 5 min) and short duration (less than 15 min).

CONCLUSION

In CIBP, worst pain most accurately reflects the characteristics of pain flares and functional impairment. Breakthrough pain is often unpredictable, sudden onset and short duration. Further characterization studies of CIBP in the broader cancer population are needed.

Breakthrough pain in oncology: a longitudinal study

CONTEXT

Existing studies on breakthrough pain (BP) have reported different prevalence rates because of different settings, populations, and assessment methods. These studies have used cross-sectional designs, and the relationship of BP with analgesic treatment has not been evaluated.

OBJECTIVES

The aim of this study was to longitudinally assess BP in cancer patients admitted to oncology units.

METHODS

A consecutive sample of patients admitted to oncology centers was selected. At admission (T0), three months after admission (T3), and six months after admission (T6), data on background pain and BP were recorded. BP was assessed in terms of its intensity, duration, number of episodes, onset with movement, spontaneous relief after stopping activity, limitation of physical activity, and effectiveness of analgesics.

RESULTS

Three hundred two patients completed the study. At T0, T3, and T6, 39%, 38%, and 33% patients, respectively, had continuous pain (P=0.294). Pain intensity significantly decreased (P=0.004 and 0.027 at T3 and T6, respectively). Most patients had BP at T0 (87.1%), T3 (80.9%), and T6 (73.2%), and there was a significant decrease in the prevalence of BP over time (P=0.016). Of 149 patients with BP, pain on movement was recorded in 43.6%, 43.4%, and 32.4% at T0, T3, and T6, respectively (P=0.228). Pain spontaneously decreased or ceased when stopping physical activity in 66%, 56%, and 62% at T0, T3, and T6, respectively (P=0.537). Pain on movement strongly limited physical activity in most patients.

CONCLUSION

These data expand current information about BP and underline the need for a longitudinal assessment of a phenomenon that is invariably dependent on stage of disease, patient, and therapeutic factors.

Fentanyl buccal tablet for the treatment of breakthrough pain: pharmacokinetics of buccal mucosa delivery and clinical efficacy

The treatment of breakthrough pain (BTP), a transitory exacerbation of pain that occurs on a background of otherwise-controlled, persistent pain, requires an opioid formulation and/or method of administration that can provide rapid and extensive systemic exposure. Fentanyl buccal tablet (FBT; FENTORA^®, Cephalon, Inc.) employs OraVescent^® drug delivery technology, which enhances the rate and extent of fentanyl absorption. OraVescent technology enhances the oral dissolution and buccal absorption of fentanyl, which facilitates rapid uptake of fentanyl into the bloodstream, reducing gastrointestinal absorption and minimizing extensive first-pass metabolism. The resulting pharmacokinetic profile of FBT is characterized by greater bioavailability and a higher early systemic exposure compared with the earlier oral transmucosal fentanyl citrate formulation. In clinical studies of opioid-tolerant patients with cancer-related and noncancer-related BTP, FBT has provided consistent and clinically relevant improvements in pain intensity and pain relief relative to placebo, with a safety and tolerability profile that is generally typical of that observed with other potent opioids. The pharmacokinetic properties of FBT allow for meaningful clinical efficacy, with an onset of action that closely matches the onset of BTP.

Prevalence and characteristics of breakthrough pain in patients with head and neck cancer: a cross-sectional study

BACKGROUND

Approximately one half to two thirds of patients with cancer-related pain experience breakthrough pain (BTP) in their daily activities.

OBJECTIVE

This is the first report to determine the prevalence and characteristics of BTP experienced by patients with head and neck cancer.

METHODS

This was a prospective cross-sectional study conducted in patients with head and neck cancer on stable doses of opioid (morphine) for at least 1 week. This study was designed as a cross-sectional study using a series of breakthrough pain questionnaires (BPQ).

RESULTS

Prevalence of BTP in our study was 48% (average of 3.85 episodes per day) of which more than 50% of episodes were of gradual onset but with severe intensity. Incident pain was predominate (50%) followed by spontaneous (25%) and end of dose failure (20%) and in 5% the nature of pain was unknown or mixed. Unlike other studies the onset of BTP in this present study with head and neck cancer was more gradual and lasted longer than 30 minutes.

CONCLUSIONS

Patients with head and neck cancer do suffer a lot because of the high incidence of BTP (48%). The majority of patients suffering from BTP are not satisfied at all with the measures taken for their BTP. The majority of patients in India have head and neck cancer; we must approach this matter as a challenge and new technique and therapy should be introduced for the benefit of these patients.

Breakthrough pain in advanced cancer patients followed at home: a longitudinal study

The aim of this study was to longitudinally assess breakthrough pain (BP) in advanced cancer patients who were admitted to home palliative care. One hundred and one consecutive patients who were admitted to one of the two home care programs and were representative of the cancer population followed at home in Italy were included. Patients were excluded only if at admission they were cognitively impaired or too unwell to provide reliable answers to questions regarding data collection. At admission (T(0)), and one month later (T(1)), data were recorded about the pharmacological treatment of background pain and its effectiveness; the presence of BP and its intensity, duration, and number of episodes; the occurrence of BP induced by movement; spontaneous relief after stopping activity and limitation of physical activity because of pain on movement; the analgesic drugs prescribed for BP; and the effectiveness of BP medication. After the initial assessment, patients received analgesics for background pain and BP, as well as symptomatic treatment usually provided at home, according to local policies and protocols. At T(0), 70.2% of patients were receiving analgesic drugs, and 52% of them had uncontrolled pain. BP was reported by 49.2% of these patients and had a mean duration and number of episodes per day of 35.1 minutes (+/-35.0) and 2.4 (+/-1.5), respectively. Of patients with BP, 65.7% had pain on movement, which decreased spontaneously after stopping activity in 73.9%. Physical activity was strongly limited in 78.2% of these patients. Most patients did not have a BP medication prescription. At T(1), a larger number of patients were receiving analgesics (P<0.002), and the number of patients with BP medication significantly increased (P<0.001). The incidence of BP and pain on movement decreased (33% and 38.5%, respectively). This longitudinal study suggests that BP is a dynamic entity dependent on several factors, including analgesic treatment and the course of disease. This helps explain the different incidences reported in previous studies performed in different settings and conditions.

Fentanyl buccal tablet for the treatment of breakthrough pain in opioid-tolerant patients with chronic cancer pain: A long-term, open-label safety study

BACKGROUND

This study assessed the long-term safety and tolerability of fentanyl buccal tablet (FBT) in opioid-tolerant patients with cancer and breakthrough pain (BTP) who were either naive to FBT or had completed 1 of 2 previous double-blind, placebo-controlled FBT studies (rollover patients).

METHODS

Patients who were FBT-naive underwent titration to find a successful FBT dose. Rollover patients used a previously identified successful dose of FBT. Patients who achieved a successful dose were eligible to enter a maintenance phase (>or=12 months). Safety assessments included adverse events (AEs), physical and neurologic examinations, and clinical laboratory tests.

RESULTS

Two hundred thirty-two patients were enrolled. A total of 112 entered titration; 79 identified a successful FBT dose, and 77 of these patients entered the maintenance phase along with 120 rollover patients (n = 197). AEs resulted in discontinuation of therapy for 33% of patients. The most common AEs were generally typical of opioids administered to cancer patients. All serious AEs were considered to be related to the patients' underlying conditions, except for 1 incident of FBT-related drug withdrawal syndrome. Sixty patients died after enrollment because of disease progression. Fifteen (6%) patients experienced >or=1 application-site AE, all of which were considered by investigators to be related to FBT.

CONCLUSIONS

FBT was generally well tolerated and had a favorable safety profile in the long-term (>or=12 months) management of patients with persistent cancer pain and BTP. No unexpected AEs occurred. Safety and tolerability was similar to that observed in short-term studies.

Classification of pain in cancer patients--a systematic literature review

One of the aims of the European Palliative Care Research Collaborative (EPCRC) is to achieve consensus on a classification system for cancer pain. We performed a systematic literature review to identify existing classification systems and domains/items used to classify cancer patients with pain. In a systematic search in the databases Medline and Embase, covering 1986-2006, 692 hits were obtained. 92 papers were evaluated to address pain classification. Six standardised classification systems were identified; three of them systematically developed and partially validated. Both pain characteristics and patient characteristics relevant for cancer pain classification were included in the classification systems. All but one of the standardised systems aim at predicting treatment response or adequacy of treatment. Several domains and items used to describe cancer pain but not formally described as part of a classification system were also identified and systematized. The existing approaches to pain classification in cancer patients are different, mostly not thoroughly validated, and none is widely applied. An internationally accepted classification system for cancer pain could improve research and cancer pain management. This systematic review suggests a need for developing an international consensus on how to classify pain in cancer patients.

Breakthrough cancer pain: review of prevalence, characteristics and management

Breakthrough pain has been associated with a reduced likelihood of adequate pain control. Despite the large and variable incidence of this phenomenon due to varied definitions of this type of pain, only a few studies have been conducted to assess and effectively treat breakthrough pain though the importance of managing breakthrough pain has been acknowledged by all. A large number of drugs from various classes and novel methods of administration like nasal and transmucosal buccal route, as in the case of fentanyl, have been used in these studies to manage this type of pain. A drug is needed with a quick onset of action and optimal duration that matches the characteristics of breakthrough pain. Some steps have been taken in earlier studies which used nasal formulation of fentanyl as it was found to achieve adequate and quick pain relief. However, further studies are required to confirm this so that in the future we can have as effective protocols for managing breakthrough pain as we have today for managing persistent pain as given by the World Health Organization.

A new transmucosal drug delivery system for patients with breakthrough cancer pain: the fentanyl effervescent buccal tablet

Breakthrough pain, a transitory severe pain with the background of otherwise controlled persistent pain has a prevalence between 52% and 67% in outpatients with cancer. Medications for such sudden-onset pain require non-invasive delivery of a potent and short-acting opioid for rapid pain relief. Although oral transmucosal delivery of fentanyl citrate (OTFC) has been shown to provide better pain relief than a typical oral opioid administration such as morphine sulfate immediate release (MSIR) in the management of breakthrough pain in patients with cancer-related pain, newer delivery systems offer a potential for further enhancement of pain relief. The fentanyl effervescent buccal tablet (FBT) formulation employs a novel drug delivery system that relies on an effervescence reaction to improve buccal fentanyl absorption. Using the effervescence reaction results in the production and dissipation of carbon dioxide with a dynamic shift in pH as the tablet dissolves. The induced low pH favors dissolution of fentanyl citrate in saliva (higher water solubility). The subsequent increase in pH thereafter favors the buccal absorption of non-ionized fentanyl across the buccal mucosa. Such a pH “pumping” mechanism increases the permeation of fentanyl into and through the buccal to the vascular system from where the agent is transported to the specific opioid receptor sites in the CNS. Compared with OTFC, data in healthy volunteers show that the effervescence reaction employed in FBT increases the total amount and the speed of absorption of fentanyl being absorbed. Compared with OTFC there is an increase in peak fentanyl blood concentrations, and an enhancement of the amount of buccal delivery of fentanyl. Such favorable data are underlined by the results of clinical studies where the FBT technology was studied in patients with breakthrough pain in chronic malignant pathologies.

Management of breakthrough pain in patients with cancer

Breakthrough pain (BTP) in patients with cancer lacks a consensus definition and is subsequently inadequately diagnosed and assessed, therefore making it more challenging to manage. Cancer pain is generally moderate to severe in intensity and persistent in nature. Despite the problematic definition of BTP, it is generally described as having similar intensity, but may also be transitory and variable in predictability. Most breakthrough analgesia fails to be effective in the time required for BTP. No useful analgesia is therefore provided but drug adverse effects escalate. Cancer pain management relies on the WHO analgesic ladder. The frequency of BTP and its inadequate management means that it has significant adverse effects on patients, their families and those involved in their care. This article outlines a systematic, clinical and evidence-based approach to managing BTP in patients with cancer that emphasizes a holistic approach and an understanding of multidimensional 'total pain'. Guidelines for managing BTP are presented and areas of developing research are identified.

Demographic, clinical, and pain characteristics are associated with average pain severity groups in a sample of oncology outpatients

Cut-points (CP) for pain severity are useful because they may help clinicians to identify patients with clinically significant pain. However, a need exists to evaluate whether different pain severity groups differ on selected demographic, clinical, and pain characteristics, as well as on factors that may be amenable to psychoeducational interventions such as self-efficacy for pain management, coping strategies, and barriers to pain management. In this cross-sectional study of 210 oncology outpatients with pain, an optimal CP of 4 was found using ratings of average pain intensity. The variables that provided a unique contribution to the prediction of membership in the >4 CP group were gender, presence of breakthrough pain, comorbidities, barriers to pain management, and total self-efficacy for pain management. In addition, patients in the >4 CP group reported lower scores on physical, role, cognitive, and global health function.

PERSPECTIVE

An average pain CP of >4 could be used to screen oncology outpatients with clinically significant pain. Clinicians must consider a number of demographic, clinical, and pain characteristics as part of their pain assessment procedures. The effectiveness of psychoeducational interventions aimed at barriers and patients self-efficacy for pain management need to be tested.

An observational study of oncology patients' utilization of breakthrough pain medication

The aim of this study was to determine utilization of breakthrough pain medication among a community-dwelling group of oncology patients. The subjects were recruited from patients attending the oncology outpatient department and oncology day unit. The protocol involved completion of a study-specific proforma: the information collected included demographic information (i.e., age, gender), cancer diagnosis, background cancer pain management, breakthrough pain characteristics (i.e., frequency, duration, intensity), and breakthrough cancer pain management. One hundred twenty patients participated in the study. Eighty-seven patients were experiencing breakthrough pain, although only 81 patients had been prescribed a strong opioid as breakthrough medication. Three patients had never taken the breakthrough medication, because of concerns about overdosing, concerns about tolerance, and absentmindedness about the existence of breakthrough medication. Of the remaining patients, 15 used the opioid every time they experienced breakthrough pain, whereas 63 used the opioid only some of the times they experienced breakthrough pain. The patients' impetus for taking breakthrough medication varied (e.g., onset of pain, duration of pain, intensity of pain), and the patients' reasons for not always taking breakthrough medication also varied (e.g., lack of intensity of pain, side effects of breakthrough medication, concerns about side effects of breakthrough medication). This study confirms that most patients do not take breakthrough medication every time they experience breakthrough pain. It also identified educational needs around the management of breakthrough pain for both patients and health care professionals.

The MERITO Study: a multicentre trial of the analgesic effect and tolerability of normal-release oral morphine during 'titration phase' in patients with cancer pain

Adequate and rapid pain control is one of the main goals of cancer pain treatment. The objective of this study was to assess the effect and tolerability of oral normal-release morphine during the initial phase of treatment in patients with moderate-to-severe cancer pain. Consecutive patients naïve to strong opioids received normal-release morphine 5 or 10 mg every 4 h during the titration phase (first 5 days), depending on previous analgesic therapy. Pain intensity was assessed using an 11-point Numerical Rating Scale (0-10), and data were recorded in a patient-compiled diary. The primary endpoint was the proportion of time with pain control (a reduction of at least 50% with respect to the baseline pain score) during the titration phase. A total of 159 consecutive patients (102 men; mean age 65 years) with cancer-related pain were enrolled. Pain control was observed for 75% (95% CI 70-80) of the follow-up period in the intent-to-treat population. Overall, 50% and 75% of patients achieved pain control within 8 and 24 h after starting normal-release morphine therapy respectively. The mean pain score was 7.63 points at baseline, and decreased to 2.43 and 1.67 points (both P<0.001) at days 3 and 5 respectively. The most commonly reported adverse events were somnolence (24% of patients), constipation (22%), vomiting (13%), nausea (10%) and confusion (7%). Normal-release morphine results in rapid and satisfactory pain control, and is well tolerated, during the strong-opioid titration phase in patients with moderate-to-severe cancer pain.

Oral transmucosal fentanyl citrate in cancer pain management: a practical application of nanotechnology

Pain is experienced by most cancer patients and represents an important issue in the clinical setting. Breakthrough pain is a transitory flare of pain that occurs in most cancer patients on a background of otherwise controlled persistent pain. Treatment of breakthrough pain is a challenging phenomenon. Oral transmucosal fentanyl citrate (OTFC; Actiq, Cephalon, UK), a new opioid formulation with a unique delivery system, utilizing the advantages that nanotechnology offers, reflects the characteristics of breakthrough pain (rapid onset of action and short duration), which makes it an effective treatment to cancer patients who are already receiving opioids and continue to experience such flares of pain. Oral transmucosal fentanyl citrate is specifically developed and approved for the management of breakthrough pain in cancer patients and it has the potential to be a useful tool for clinicians.

Fentanyl buccal tablet for the relief of breakthrough pain in opioid-tolerant adult patients with chronic neuropathic pain: a multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Patients with chronic noncancer pain, including neuropathic pain, may have transitory exacerbations of pain (median duration, 60 minutes), termed breakthrough pain (BTP), that may reach peak intensity within minutes. Typical short-acting oral opioids may not provide sufficiently rapid relief (30- to 60-minute onset of analgesia). The fentanyl buccal tablet (FBT) provides a rapid onset of analgesia (10-15 minutes) by enhancing fentanyl absorption across the buccal mucosa.

OBJECTIVE

This study evaluated the efficacy and tolerability of FBT in opioid-tolerant patients with BTP associated with chronic noncancer neuropathic pain.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled study in men and women aged 18 to 80 years who were opioid tolerant; had a >/= 3-month history of chronic persistent neuropathic pain associated with diabetic peripheral neuropathy, postherpetic neuralgia, traumatic injury, or complex regional pain syndrome; and reported having episodes of BTP. After an open-label titration period to identify an effective FBT dose (the dose at which the patient reported receiving adequate pain relief within 30 minutes after administration of a single tablet of that dose during at least 2 of 3 BTP episodes), patients were randomly assigned to treat 9 consecutive episodes of BTP over the next 21 days with 1 of 3 double-blind dose sequences of FBT and placebo tablets. Pain intensity (PI) (rated on an 11-point pain scale, from 0 = no pain to 10 = worst pain) and other outcomes were assessed before dosing and for 2 hours after dosing. The primary efficacy measure was the sum of PI differences (PIDs) for the first 60 minutes (SPID(60)). Secondary efficacy measures included the proportion of BTP episodes with >/= 33% and >/= 50% improvement in PI from baseline; PID at other time points (5, 10, 15, 30, 45, 60, 90, and 120 minutes after dosing); pain relief (PR) at the same time points (rated on a 5-point Likert scale from 0 = none to 4 = complete); proportion of BTP episodes with meaningful PR; time to meaningful PR; and proportion of BTP episodes in which supplemental medication was required after administration of study drug. Adverse events (AEs) spontaneously reported by the patient or elicited by the investigator were recorded throughout the study.

RESULTS

Of 102 patients in the open-label titration period, 80 identified an effective dose of FBT and 79 entered the double-blind phase. Of these 79 patients, 77 (97%) completed the study and 75 (95%) were evaluable for efficacy. Of the 79 patients who entered the double-blind phase, 63% were women and 92% were white; their mean (SD) age was 48.3 (10.42) years, and their mean weight was 96.8 (33.42) kg. Baseline demographic and pain characteristics were similar between the overall population and the double-blind population. SPID(60) was significantly greater for BTP episodes treated with FBT compared with those in which placebo was administered (mean [SE], 9.63 [0.75] vs 5.73 [0.72], respectively; P < 0.001). Significant differences between FBT and placebo were seen beginning at 10 minutes for PID (mean, 0.740 [0.149] vs 0.427 [0.081]; P < 0.047) and PR (mean, 0.561 [0.087] vs 0.324 [0.056]; P < 0.001). A >/= 33% improvement in PI from baseline was seen in a greater proportion of BTP episodes treated with FBT compared with placebo from 10 minutes (9% vs 3%; P = 0.008) through 2 hours (66% vs 37%; P < 0.001). Patients were almost 4 times less likely to require supplemental opioids when BTP episodes were treated with FBT compared with placebo (odds ratio = 0.28; 95% Cl, 0.18-0.42). AEs were reported by 64 (63%) of 102 patients. The most commonly reported AEs were those typical of opioids (nausea [13%], dizziness [13%], somnolence [10%], and vomiting [5%]) and occurred more often during the dose-titration phase (55/102 [54%]) than during the double-blind phase (22/79 [28%]).

CONCLUSION

In these opioid-tolerant patients with chronic neuropathic pain who identified an effective FBT dose, FBT had a rapid onset of action and was effective and well tolerated in the treatment of BTP.

The rationale for a multimodal approach in the management of breakthrough cancer pain: a review

Breakthrough pain has been described differently in various countries, and not surprisingly, recommendations for its management vary according to the institution. Usually when breakthrough pain occurs, the patient's pain has already been managed according to the World Health Organization 3-step ladder for cancer pain. After this point, the treatment choice is usually based on clinical judgment, the physician's personal experience with interventional procedures, and local resources available. Opioids remain the mainstay of the management of breakthrough cancer pain. However, the combination of radio-oncology, adjuvant drugs, and interventional pain procedures can improve pain relief. This review addresses those questions and proposes a multimodal approach to manage breakthrough cancer pain.

Recognition and diagnosis of breakthrough pain

OBJECTIVE

To review major clinical issues related to recognition and diagnosis of breakthrough pain.

ISSUES

Persistent pain and breakthrough pain (BTP) are distinct clinical entities that should be recognized, diagnosed, and treated individually. BTP is common in patients with cancer and a variety of other chronic diseases. Reported incidence of BTP varies widely from 16% to 95% of those with persistent pain syndromes. Such variability is likely due to lack of a clear consensus on the definition of BTP. It is most commonly defined as an abrupt, short-lived, and intense pain that "breaks through" the around-the-clock analgesia that controls persistent pain. The three subtypes of BTP are incident, idiopathic, and end-of-dose failure. BTP also is categorized as somatic, visceral, neuropathic, or mixed. Appropriate assessment of the patient takes into consideration source, severity, pattern, subtype, and cause of pain. Successful treatment is important because BTP has a profound impact on the patient's quality of life, as well as cost of health care. BTP is likely to be underdiagnosed and undertreated because of the lack of consensus on its definition and unwarranted concerns among health care professionals and patients about overmedicating. Additionally, and for reasons not entirely clear, many physicians and other health care providers place a low priority on pain management and underrecognize the occurrence of BTP in patients with persistent pain.

CONCLUSION

Greater knowledge and awareness of BTP in cancer and nonmalignant conditions will lead to improved recognition and diagnosis of BTP and ultimately to more effective treatment and enhanced quality of life for these patients.

A Randomized, Placebo-controlled Study of Fentanyl Buccal Tablet for Breakthrough Pain in Opioid-treated Patients With Cancer

OBJECTIVES

Cancer-related breakthrough pain (BTP) is typically managed with a short-acting oral opioid, taken as needed during a fixed-schedule opioid regimen. The conventional approach may not provide the onset of analgesia required for BTP for many patients, because the onset of analgesia with short-acting opioids lags behind the time course of the majority of episodes of BTP. The fentanyl buccal tablet (FBT) employs a novel delivery system that enhances the rate and extent of absorption of fentanyl through the buccal mucosa. This double-blind, randomized, placebo-controlled study evaluated the efficacy, safety, and tolerability of FBT in opioid-treated patients with cancer-related BTP.

METHODS

After an open-label titration (N=123) to identify an effective FBT dose to treat BTP episodes, 77 patients were randomly assigned to 1 of 18 prespecified dose sequences of 10 tablets (7 FBT and 3 placebo). Pain intensity, pain relief (PR), and global performance of the medication were recorded at regular time intervals between 15 and 60 minutes. Pain intensity differences (PID), the summed PID (SPID), and summed total PR were calculated. The SPID at 30 minutes (SPID30) was the primary efficacy variable. Adverse events were reported.

RESULTS

Sixty-five percent (80/123) of patients were titrated to an effective dose. The mean (SE) SPID30 for FBT was 3.0+/-0.12 versus 1.8+/-0.18 for placebo (P<0.0001). Measures of PR, PID, SPID, summed total PR, and patient ratings of global performance of medication significantly favored FBT over placebo at all time points. Adverse events were typical of opioid drugs. Poor oral tolerability was noted in 2 patients.

CONCLUSIONS

FBT is efficacious and safe in the treatment of cancer-related BTP.

Breakthrough pain in opioid-treated chronic non-malignant pain patients referred to a multidisciplinary pain centre: a preliminary study

BACKGROUND

Breakthrough pain (BTP) has not formerly been discussed as such in chronic non-malignant pain patients referred to pain centres and clinics. The purpose of the study was to investigate the prevalence, characteristics and mechanisms of BTP in opioid-treated chronic non-malignant pain patients referred to a pain centre and to assess the short-term effects of pain treatment.

METHODS

Patients were assessed at referral (T(0)) and after a treatment period of 3 months (T(3)) using the visual analogue scale (VAS) of the brief pain inventory (BPI) within somatic nociceptive, neuropathic and/or visceral pain conditions, the mini mental state examination (MMSE) and the hospital anxiety and depression scale (HADS). The main treatment intervention from T(0) to T(3) was to convert short-acting oral opioids to long-acting oral opioids and to discontinue on demand and parenteral use of opioids.

RESULTS

Thirty-three patients were assessed at T(0) and 27 at T(3). The prevalence of BTP declined significantly from T(0) (90%) to T(3) (70.4%). Worst, least, average and current pain intensities as well as duration of BTP were significantly reduced from T(0) to T(3.) The majority of BTPs were exacerbation of background pain assumed to be of the same pain mechanisms. High average pain intensity (BPI) was significantly associated with high scores for both anxiety and depression (HADS).

CONCLUSION

BTP in chronic non-malignant pain patients seems to be surprisingly frequent and severe. Stabilizing the opioid regimen seems to reduce pain intensity in general as well as the intensity and duration of BTP. Average pain intensity was associated with anxiety and depression.

Opioids for the management of breakthrough (episodic) pain in cancer patients

BACKGROUND

Breakthrough pain is a transient increase in pain intensity over background pain. It is a common and distinct component of cancer pain that can have a negative impact for both the patient and carers' quality of life. Breakthrough pain is usually related to background pain and is typically of rapid onset, severe in intensity, and generally self-limiting with an average duration of 30 minutes. At present the current approach to managing breakthrough pain is using supplemental analgesia (also known as rescue medication) at a dose proportional to the total around-the-clock (ATC) opioid dose.

OBJECTIVES

This review explores and assesses the evidence for the use of opioids in the management of breakthrough pain in patients with cancer.

SEARCH STRATEGY

MEDLINE (1966 to 2005), EMBASE (1980 to 2005), CancerLit (1993 to 2005), CINAHL (1982 to 2005) and Cochrane databases were searched. Handsearching of medical journals and reference from key textbooks was undertaken and drug companies contacted for unpublished data. There was no language restriction. Date of most recent search: January 2005.

SELECTION CRITERIA

Randomized controlled trials of opioids used as rescue medication against active or placebo comparator in patients with cancer pain were included. Outcome measures sought were reduction in pain intensity measured by an appropriate scale, adverse effects, attrition, patient satisfaction and quality of life. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

Eligible studies were selected and examined independently by the two reviewers. Full text was retrieved if any uncertainty about eligibility remained. Non-English texts were screened. Quality assessment and data extraction were conducted using standardised data forms. Drug and placebo dose, titration, route and formulation were compared and detail of all outcome measures (if available) recorded.

MAIN RESULTS

Four studies (393 participants) met the inclusion criteria, all were concerned with the use of oral transmucosal fentanyl citrate (OTFC) in the management of breakthrough pain. Two studies examined the titration of OTFC, one study compared OTFC to normal release morphine and one study compared OTFC to placebo.OTFC was shown to be an effective treatment for breakthrough pain. When compared to placebo and morphine, participants gave lower pain intensity scores and higher pain relief scores for OTFC at all time points. Global assessment scores also favoured OTFC.

AUTHORS' CONCLUSIONS

There is evidence that OTFC is an effective treatment in the management of breakthrough pain. The randomised trial literature for the management of breakthrough pain is small and no trials were found for other opioids. Given the importance of this subject, more trials need to be undertaken.

Controversies in pharmacotherapy of pain management

Since the establishment of the WHO three-step ladder for management of cancer pain, several controversies have arisen, which are partly due to new drug development, reformulations of older analgesics, and technological advancements. As a result, clinicians need clarification of several questions. Is morphine the opioid of choice for moderate to severe pain in cancer? Should combinations of opioids be used? When should spinal opioids be used to treat pain in cancer? What are the appropriate opioid doses for breakthrough pain? Should selective cyclo-oxygenase (COX) 2 inhibitors be used? What is the best tactic to treat neuropathic pain, and what first-line adjuvant analgesic should be used? And do bisphosphonates relieve bone pain in cancers other than breast cancer and myeloma? This review addresses these questions.

A multicenter study of the revised Edmonton Staging System for classifying cancer pain in advanced cancer patients

The comparative analysis of analgesic interventions for cancer pain is greatly compromised by the lack of well-validated and clinically acceptable tools, which allow a composite classification of pain and patient population characteristics. Although the Edmonton Staging System (ESS) for cancer pain was developed for this purpose, clinical and research utility has been limited due to problems associated with the assessment of some items, especially in relation to definitions and terminology. To overcome these limitations, we designed a revised ESS (rESS) and conducted a multicenter study to determine its inter-rater reliability and predictive value. In revising the rESS, we hypothesized that patients with less problematic pain features would require a shorter time to achieve stable pain control, require less complicated analgesic regimens, be more responsive to opioid therapy, and use lower opioid doses. The rESS items include mechanism of pain, presence or absence of incidental pain, presence or absence of psychological distress and addictive behavior, and level of cognitive function. Patients with cancer pain who were consecutively admitted to two different hospice centers, an acute care consultation service in a teaching hospital or a tertiary palliative care unit in a second teaching hospital were evaluated for study entry. Two independent palliative care specialists completed the rESS where possible within 24 hours of each other. Patients' pain ratings and opioid consumption were recorded daily until the study endpoint (i.e. achievement of stable pain control, discharge or death). Seven hundred and forty-six patients were eligible for study entry and of these, 619 (83%) had a pain syndrome. Inter-rater reliability estimates ranged from 0.67 (pain mechanism) to 0.95 (presence of addiction). In the univariate Cox regression analysis, younger patients (<60), as well as patients with neuropathic pain, incidental pain, psychological distress, or co-morbid psychological distress and addiction, required a significantly longer time to achieve stable pain control (P<0.05). In the multivariate Cox regression analysis, only age (<60), neuropathic pain and incidental pain were significantly associated with time to reach stable pain control (P<or=0.05). Patients with neuropathic or incidental pain used significantly more modalities to achieve stable pain control (P<0.01). Patients with neuropathic pain, incidental pain, as well as the presence of psychological distress or addiction, required a higher final mean morphine equivalent daily dose (MEDD) (P<0.001). A comparison of the rESS with the ESS demonstrated the ineffectiveness of the ESS prognostic staging system for predicting achievement of stable pain control. These findings confirm the study hypothesis, suggesting that the rESS appears to have good predictive value and a moderate to high inter-rater reliability. We suggest the rESS should prove to be a useful tool in clinical practice, and in the comparison of cancer pain populations in research studies.

Characterization of the early pharmacodynamic profile of oral methadone for cancer-related breakthrough pain: a pilot study

Methadone is effective for chronic cancer pain, but its early pharmacodynamic profile and effectiveness for breakthrough pain remain uncertain. This was an open-label, non-randomized, crossover study comparing the use of oral methadone for breakthrough pain with patients' usual opioid. Study variables included pain intensity (pretreatment and at 10-minute intervals post treatment), treatment-related side effects, and treatment satisfaction. In 37 discrete episodes of breakthrough pain, onset of analgesic effect of a titrated dose of oral methadone was rapid for all patients; 3 of 6 study patients experienced an onset of relief by 10 minutes post-ingestion. The adverse effect profile of oral methadone was not different from patients' usual 'rescue' opioid, and patients were moderately to completely satisfied with oral methadone as a breakthrough pain medication. These observations suggest that oral methadone can have a rapid onset of analgesic action and may have a legitimate role in the management of cancer-related breakthrough pain.

Breakthrough pain characteristics and syndromes in patients with cancer pain. An international survey

Breakthrough pain (BKP) is a transitory flare of pain that occurs on a background of relatively well controlled baseline pain. Previous surveys have found that BKP is highly prevalent among patients with cancer pain and predicts more severe pain, pain-related distress and functional impairment, and relatively poor quality of life. An international group of investigators assembled by a task force of the International Association for the Study of Pain (IASP) evaluated the prevalence and characteristics of BKP as part of a prospective, cross-sectional survey of cancer pain. Fifty-eight clinicians in 24 countries evaluated a total of 1095 patients with cancer pain using patient-rated items from the Brief Pain Inventory (BPI) and observer-rated measures. The observer-rated information included demographic and tumor-related data, the occurrence of BKP, and responses on checklists of pain syndromes and pathophysiologies. The clinicians reported BKP in 64.8% of patients. Physicians from English-speaking countries were significantly more likely to report BKP than other physicians. BKP was associated with higher pain scores and functional interference on the BPI. Multivariate analysis showed an independent association of BKP with the presence of more than one pain, a vertebral pain syndrome, pain due to plexopathy, and English-speaking country. These data confirm the high prevalence of BKP, its association with more severe pain and functional impairment, and its relationship to specific cancer pain syndromes. Further studies are needed to characterize subtypes of BKP. The uneven distribution of BKP reporting across pain specialists from different countries suggests that more standardized methods for diagnosing BKP are needed.