The Polyanalgesic Consensus Conference (PACC)®: Updates on Clinical Pharmacology and Comorbidity Management in Intrathecal Drug Delivery for Cancer Pain.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians based on expertise with international representation to establish evidence-based guidance on using intrathecal drug delivery in chronic pain treatment. This Polyanalgesic Consensus Conference (PACC)® project's scope is to provide evidence-based guidance for clinical pharmacology and best practices for intrathecal drug delivery for cancer pain. MATERIALS AND METHODS: Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Meeting Abstracts, and Scopus from 2017 (when the PACC last published guidelines) to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations were based on the strength of evidence, and when evidence was scant, recommendations were based on expert consensus. RESULTS: The PACC evaluated the published literature and established evidence- and consensus-based expert opinion recommendations to guide best practices in treating cancer pain. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The PACC recommends best practices regarding the use of intrathecal drug delivery in cancer pain, with an emphasis on managing the unique disease and patient characteristics encountered in oncology. These evidence- and consensus-based expert opinion recommendations should be used as a guide to assist decision-making when clinically appropriate.

Antiplatelet and Wound Healing Implications of Immunotherapy and Targeted Cancer Therapies in the Perioperative Period.

The traditional paradigm of oncologic treatment centered on cytotoxic chemotherapy has undergone tremendous advancement during the last 15 yr with the advent of immunotherapy and targeted cancer therapies. These agents, including small molecule inhibitors, monoclonal antibodies, and immune-checkpoint inhibitors, are highly specific to individual tumor characteristics and can prevent cell growth and tumorigenesis by inhibiting specific molecular targets or single oncogenes. While generally better tolerated than traditional chemotherapy, these therapies are associated with unique constellations of adverse effects. Of particular importance in the perioperative and periprocedural settings are hematologic abnormalities, particularly antiplatelet effects with increased risk of bleeding, and implications for wound healing. This narrative review discusses targeted cancer therapies and provides recommendations for physicians managing these patients' care as it relates to procedural or surgical interventions.

Management of Cancer-Related Pain With Intrathecal Drug Delivery: A Systematic Review and Meta-Analysis of Clinical Studies.

BACKGROUND: Despite increased attention paid to assessment and management, pain continues to be a prevalent and undertreated symptom in patients with cancer. Intrathecal drug delivery (IDD) is a therapeutic option that allows targeted delivery of analgesics to the intrathecal space. OBJECTIVE: The aim of this review was to examine the efficacy of managing cancer-related pain with IDD. Secondary objectives included the effects of IDD on systemic opioid use and infection rates. EVIDENCE REVIEW: A systematic search of the literature published between 1990 and 2019 was performed to identify studies evaluating the efficacy and/or safety of IDD with external or implanted pumps in patients with cancer-related pain. Data were extracted and meta-analyses performed to determine the mean changes in pain levels at short-, mid-, and long-term intervals; changes in opioid (oral morphine equivalent [OME]) daily dose; and infection rates. Changes were assessed compared with baseline. FINDINGS: Pain levels were decreased from baseline: On a 0 to 10 scale, mean differences were -4.34 (95% CI [-4.93 to -3.75], p < 0.001) at 4 to 5 weeks; -4.34 (95% CI [-5.07 to -3.62], p < 0.001) at 6 to 12 weeks; and -3.32 (95% CI [-4.60 to -2.04], p < 0.001) at >6 months. Weighted mean OME consumption was reduced by 308.24 (SE = 22.72) mg/d. Weighted mean infection rates were ∼3% for external and implanted pumps. CONCLUSIONS: Meta-analyses show a statistically significant and sustained decrease in cancer pain with IDD, compared with baseline. Systemic opioid consumption was reduced on average by >50% after IDD. Infection rates were comparable with other indications.

Dorsal Versus Ventral Intrathecal Catheter Tip Location and Effect on Dose Escalation and Opioid Use in Patients With Cancer Pain.

OBJECTIVES: In the practice of intrathecal drug delivery, consensus exists regarding the cephalad to caudad location of the catheter tip relative to dermatomal distribution of pain. However, data are lacking on the importance of dorsal vs ventral tip location relative to the spinal cord. We hypothesize that a dorsally placed catheter tip improves efficacy because of closer proximity to nociceptive pathways. MATERIALS AND METHODS: A retrospective review of 298 patients with cancer with intrathecal drug delivery systems implanted at the Huntsman Cancer Institute from May 2014 to June 2020 was performed. Patients were stratified by catheter tip location zones based on available radiographic studies. Patient-controlled intrathecal medication dose requirements and rate of change were compared with catheter zone and other variables, including the presence of adjuncts such as bupivacaine and ziconotide. RESULTS: A total of 158 patients were suitable for analysis demonstrating a dorsal tip in 63.9% (n = 101) and ventral tip in 36.1% (n = 57), with a median follow-up of 17 days (interquartile range [IQR], 10-24). There was no difference in daily dose change from implant to discharge between the dorsal group 8.2% (IQR, 0.0-41.5) and ventral group 20.8% (IQR, 0.0-66.7; p = 0.12). Daily dose change from discharge to follow-up was 2.6% (IQR, 0.0-7.1) in the dorsal group and 1.8% (IQR, 0.0-5.7) in the ventral group (p = 0.92). Catheter tip location had no impact on systemic opioid use. CONCLUSIONS: We did not find significant associations between dorsal vs ventral catheter tip location and measures of pain relief, including change in intrathecal dose or systemic opioid use.

Initial Intrathecal Dose Titration and Predictors of Early Dose Escalation in Patients With Cancer Using a 100:1 Oral to Intrathecal Morphine Conversion Ratio.

OBJECTIVE: Pain is common in patients with advanced cancer, and intrathecal drug delivery (IDD) has been successfully used for recalcitrant pain. We report on our experience using a 100:1 oral-to-intrathecal morphine conversion ratio for initial dosing and factors predictive of early dose escalation. MATERIALS AND METHODS: Retrospective review of an intrathecal drug delivery system (IDDS) data base at the Huntsman Cancer Institute-University of Utah in cancer patients initiated on IDD with morphine or hydromorphone. Demographic characteristics, preoperative opioid use, and initial and hospital discharge IDD settings were collected. RESULTS: A total of 275 patients were identified between June 2014 and May 2020. The median oral-to-intrathecal morphine conversion ratio for initial IDD dosing was 105.5:1 (interquartile range [IQR] 90-120, range 75-150). No serious adverse effects including respiratory depression or sedation were noted and the median length of stay was one night (IQR 1-2, range 1-22). Ninety-six percent of patients discontinued opioids immediately following IDDS implant. Initial IDD dosing was adequate in 42% of patients. Dose reduction was required in 4% prior to discharge due to nausea, patient request, weakness, pruritus, or urinary retention. Dose escalation was required in 54%, with a median dose increase of 66.7% (IQR 33-150%, range 5-1150%). Patients in the highest quartile of dose escalation, ≥70% between IDD initiation and discharge, had associations with younger age, higher preoperative opioid use, and inpatient status. No significant associations were found in patients who required dose reduction as compared to other patients. CONCLUSIONS: An oral-to-intrathecal morphine conversion ratio of approximately 100:1 for initiation of IDD in patients with cancer pain was safe and well tolerated and may facilitate rapid elimination of systemic opioids. Dose reduction was rare, while a majority of patients required further dose escalation prior to discharge.

The Effect of Measured Radiotherapy Dose on Intrathecal Drug Delivery System Function.

OBJECTIVES: Radiation therapy (RT) and intrathecal drug delivery systems (IDDS) are often used concurrently to optimize pain management in patients with cancer. Concern remains among clinicians regarding the potential for IDDS malfunction in the setting of RT. Here we assessed the frequency of IDDS malfunction in a large cohort of patients treated with RT. MATERIALS AND METHODS: Cancer patients with IDDS and subsequent RT at our institution from 2011 to 2019 were eligible for this study. Patients were excluded in the rare event that their IDDS was managed by an outside clinic and follow-up documentation was unavailable. Eighty-eight patients aged 22-88 years old (43% female, 57% male) representing 106 separate courses of RT were retrospectively identified. Patients received varying levels of radiation for treatment of cancer and cumulative dose to the IDDS was calculated. IDDS interrogation was subsequently performed by a pain specialist. Malfunction was recorded as deviation from the expected drug volume and/or device errors reported upon interrogation as defined by the manufacturer. RESULTS: Total measured RT dose to the IDDS ranged from 0 to 18.0 Gy (median = 0.2 Gy) with median dose of 0.04 Gy/fraction (range, 0-3.2 Gy/fraction). Ten pumps received a total dose >2 Gy and three received ≥5 Gy. Eighty-two percentage of patients had follow-up with a pain specialist for IDDS interrogation and all patients underwent follow-up with a healthcare provider following RT. There were zero incidences of IDDS malfunction related to RT. No patient had clinical evidence of radiation related pump malfunction at subsequent encounters. CONCLUSIONS: We found no evidence that RT in patients with IDDS led to device failure or dysfunction. While radiation oncologists and pain specialists should coordinate patient care, it does not appear that RT dose impacts the function of the IDDS to warrant significant clinical concern.

Prospective Association of Serum Opioid Levels and Clinical Outcomes in Patients With Cancer Pain Treated With Intrathecal Opioid Therapy.

BACKGROUND: Opioids remain the mainstay of cancer pain management but are associated with systemic toxicity. In refractory cancer pain, intrathecal therapy (ITT) is associated with improved pain control, reduced systemic side effects, and improved survival. It has been assumed that ITT decreases systemic serum opioid levels and their associated toxicity, but there are limited data to support this assumption. This study hypothesizes that serum opioid levels decrease with ITT. Secondary objectives include comparative measures of pain, bowel function, and other cancer-related symptoms. METHODS: Fifty-one cancer patients undergoing ITT for cancer pain were recruited in a prospective observational study. Daily oral morphine equivalency (OME) dose, serum opioid levels, Brief Pain Inventory (BPI), MD Anderson Symptom Inventory (MDASI), and a constipation questionnaire were obtained at the time of implant, and 4 and 8 weeks postoperatively. RESULTS: Average baseline daily OME was 375 mg (median, 240; interquartile range, 150-405; range, 0-3160), mean serum morphine concentration was 53.7 ng/mL (n = 17), and mean oxycodone concentration was 73.7 ng/mL (n = 20). At 4 weeks, 87.5% of patients had discontinued non-IT opioids, and 53% had undetectable (<2 ng/mL) serum opioid concentrations. At 8 weeks, 92% remained off all non-IT opioids and 59% had undetectable serum opioid levels. IT morphine doses >4.2 mg/d were invariably associated with detectable serum levels; with doses <4.2 mg, morphine was undetectable in 80% of subjects. IT hydromorphone doses >6.8 mg/d were detectable in the serum. Using linear mixed model analyses, there were statistically significant decreases in the mean "worst pain," "average pain," and MD Anderson symptom severity and interference scores at 4 and 8 weeks. This change was independent of serum opioid levels; when analyzed separately, there was no difference in the pain scores of subjects with detectable serum opioid levels compared to those with undetectable levels at 4 and 8 weeks. Constipation ranked as "quite a bit" or "very much" decreased from 58.7% to 19.2% of subjects at week 4 (P < .001) and to 37.5% at 8 weeks (P = .23). A very low complication rate was observed. CONCLUSIONS: ITT for cancer pain was associated with a marked reduction in serum opioid concentrations, with the majority of patients having undetectable serum levels. Reducing serum opioid concentrations in cancer patients may have implications with respect to restoring bowel function, improving fatigue, and promoting the integrity of antitumor immune function and warrants further study.

The Rate of Infectious Complications After Intrathecal Drug Delivery System Implant for Cancer-Related Pain Is Low Despite Frequent Concurrent Anticancer Treatment or Leukopenia.

BACKGROUND: The efficacy of intrathecal drug delivery (IDD) for cancer-related pain is well established. Cancer therapies are often associated with immunosuppression and increased risk of infection, and the rate of infection after intrathecal drug delivery system (IDDS) implant in cancer patients has been reported as 2.4%-6.3%. Our objective is to report on the rate of surgical site infections (SSI) in patients implanted with IDDS for cancer-related pain and to provide a data-driven discussion on the relationship between antineoplastic treatment, leukopenia, and other clinical or demographic characteristics and SSI. METHODS: Following local institutional review board approval, we conducted a retrospective chart review of IDDS implants from May 2014 through December 2018. Data collected included demographic data, health status, prophylactic antibiotic administration, surgery duration, presence of leukopenia (white blood cell [WBC] count of <4.0 K/µL) or moderate neutropenia (absolute neutrophil count [ANC] of <1000/µL) within the 30 days before IDDS implant, and details of antineoplastic treatment or systemic corticosteroid use in the perioperative period. This information was assessed in relation to SSI incidence up to 6 months following implant. RESULTS: Two hundred seventeen IDDS implants were identified. A majority of patients (79.3%) received ≥1 form of antineoplastic therapy within 30 days before or after implant, and 42.4% received multiple forms of antineoplastic therapy. Therapies included chemotherapy in 46.5%, immunotherapy in 28.6%, systemic steroids in 32.3%, and radiation therapy in 28.1%. One-quarter of patients (25.8%) were leukopenic within 30 days before implant, with 3.2% having moderate neutropenia. There were 2 infectious complications representing an infection rate of 0.9% (95% CI, 0.1%-3.3%), with limited shared characteristics between those experiencing SSI. CONCLUSIONS: SSI risk after IDDS placement for cancer pain is low, despite frequent concurrent antineoplastic therapy and leukopenia in the perioperative period. Concomitant cancer therapies should not be a barrier to the implementation of IDD for cancer pain.

Initiation of Intrathecal Drug Delivery Dramatically Reduces Systemic Opioid Use in Patients With Advanced Cancer.

OBJECTIVES: Pain is common in cancer, affecting more than 70% of patients with advanced disease. Intrathecal drug delivery systems (IDDS) are a well-established treatment for patients with refractory cancer pain, improving pain control and reducing associated side effects. To date, details of systemic opioid use before and after IDDS implant have not been reported. MATERIALS AND METHODS: We conducted a retrospective review of patients at Huntsman Cancer Institute-University of Utah treated with IDDS for cancer pain from May 2014 to May 2018. Oral, transdermal, and parenteral opioid use before IDDS implant was compared to use 30 days postoperatively. RESULTS: A total of 173 patients were included, 93% with stage IV disease. The pre-implant median daily oral morphine equivalent (OME) was 240 mg (interquartile range 130-390, range 0-2616 mg). OME doses >200 mg/day were required by 57% of patients, and >500 mg OME by 19% of patients. The post-implant median OME was 0 mg (interquartile range 0-0, range 0-480 mg) and 82.6% of patients discontinued systemic opioids completely. 11.0% of patients used <100 mg OME, and only 1.7% of patients used >200 mg OME. Mean OME decreased by 94% following IDDS implant (p < 0.0001) and all patients who continued to use systemic opioids required a lower OME compared to pre-implant. CONCLUSIONS: In the largest cohort of patients with advanced cancer and refractory pain treated with IDDS, implantation was associated with a dramatic reduction in systemic opioid use 30 days postoperatively, with a large majority of patients discontinuing systemic opioids. Those patients that continued systemic opioids utilized significantly lower doses as compared to their pre-implant dose.

Optimization of Radiofrequency Needle Placement in Percutaneous Cordotomy Using Electromyography in the Deeply Sedated Patient.

BACKGROUND AND OBJECTIVES: Cordotomy, the selective disconnection of the nociceptive fibers in the spinothalamic tract, is used to provide pain palliation to oncological patients suffering from intractable cancer-related pain. Cordotomies are commonly performed using a cervical (C1-2) percutaneous approach under imaging guidance and require patients' cooperation to functionally localize the spinothalamic tract. This can be challenging in patients suffering from extreme pain. It has recently been demonstrated that intraoperative neurophysiology monitoring by electromyography may aid in safe lesion positioning. The aim of this study was to evaluate the role of compound muscle action potential (CMAP) in deeply sedated patients undergoing percutaneous cervical cordotomy (PCC). METHODS: A retrospective analysis was conducted of all patients who underwent percutaneous cordotomy while deeply sedated between January 2019 and November 2022 in 2 academic centers. The operative report, neuromonitoring logs, and clinical medical records were evaluated. RESULTS: Eleven patients underwent PCC under deep sedation. In all patients, the final motor assessment prior to ablation was done using the electrophysiological criterion alone. The median threshold for evoking CMAP activity at the lesion site was 0.9 V ranging between 0.5 and 1.5 V (average 1 V ± 0.34 V SD). An immediate, substantial decrease in pain was observed in 9 patients. The median pain scores (Numeric Rating Scale) decreased from 10 preoperatively (range 8-10) to a median 0 (range 0-10) immediately after surgery. None of our patients developed motor deficits. CONCLUSION: CMAP-guided PCC may be feasible in deeply sedated patients without added risk to postoperative motor function. This technique should be considered in a group of patients who are not able to undergo awake PCC.

A cost utilization analysis of intrathecal therapy for refractory cancer pain: identifying factors associated with cost benefit.

OBJECTIVE: Intrathecal therapy (ITT) for cancer pain is characterized by high initial cost followed by low maintenance costs. Non-ITT pain management is associated with steadily increasing cumulative cost that can equal the cost of ITT over time. The intent of this modeling project is to identify factors associated with relatively rapid achievement of cost-benefit with ITT. DESIGN: A retrospective chart review was performed on 36 patients with cancer pain who underwent ITT and survived beyond 4 weeks. METHODS: Data on the cost of conventional opioid therapy prior to ITT and at 4-6 weeks were collected and projected over time. ITT costs included all intrathecal pump implantation and maintenance costs. Pre-ITT opioid regimens were stratified into high-cost conventional (HCC-high-dose, nongeneric, or use of intravenous patient-controlled analgesia, N = 12) and low-cost conventional (low-dose or generic, N = 24) regimens. RESULTS: The median daily cost of opioid medications pre-ITT was $21.26 (25th-75th percentile $10.31-78.85, range 0-$971.97) vs $0 (25th-75th percentile $0-0.70), P = 0.007, post-ITT. In the HCC group, the median daily cost was $172.47 (25th-75th percentile $67.29-406.20). The median daily cost of ITT medications was $16.01 (25th-75th percentile $9.52-23.23).When these data were used to model costs over the long term, including pump implantation costs, cost-benefit for all patients compared with conventional therapy was predicted at 344 months but at 7.4 months in the HCC group. Seven patients (19%) achieved cost equivalence within 6 months and three of these within the first 3 months. CONCLUSIONS: In selected patients on high-cost opioid regimens, ITT may become cost-beneficial within 6 months. Factors associated with earlier attainment of ITT cost-benefit include the use of parenteral therapy, high-dose opioids, and the use of nongeneric opioid products.

Controversies in intrathecal drug delivery for cancer pain.

Pain and suffering related to cancer are challenging issues that continue to deserve consideration for treatment optimization. Advances in analgesic management and control of the underlying cancer have improved symptom management, yet many patients still suffer from uncontrolled pain. Intrathecal drug delivery has an established role in the management of refractory cancer pain, but there are significant knowledge gaps in our understanding and application of this therapy. This review addresses several areas of controversy, including the importance of intrathecal catheter tip location, the necessity of an intrathecal trial and the role of intrathecal ziconotide and local anesthetics. In each area, the evidence is discussed, with an emphasis on presenting practical clinical guidance and highlighting deficiencies in our knowledge that are worthy of future investigation.

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.

Quantitative Assessment of the Incidence of Persistent Orthostatic Hemodynamic Changes After Celiac Plexus Neurolysis: A Prospective Case Series.

Celiac plexus neurolysis has been associated with orthostatic hypotension but has not been quantified prospectively or evaluated for persistence after the immediate postprocedural period. Our objective was to quantify persistent hemodynamic changes induced by celiac plexus neurolysis. In this case series of 16 patients with cancer, 8 (50%) had orthostatic hypotension alone, 3 (18.75%) developed an exaggerated postural heart rate increase (>30 beats per min), and 1 (6.25%) had both orthostatic hypotension and an increased heart rate. While the analgesic benefit of celiac plexus neurolysis is clear, the observed hemodynamic changes may be poorly tolerated in some individuals.

The American Society of Pain and Neuroscience (ASPN) Best Practices and Guidelines for the Interventional Management of Cancer-Associated Pain.

Moderate to severe pain occurs in many cancer patients during their clinical course and may stem from the primary pathology, metastasis, or as treatment side effects. Uncontrolled pain using conservative medical therapy can often lead to patient distress, loss of productivity, shorter life expectancy, longer hospital stays, and increase in healthcare utilization. Various publications shed light on strategies for conservative medical management for cancer pain and a few international publications have reviewed limited interventional data. Our multi-institutional working group was assembled to review and highlight the body of evidence that exists for opioid utilization for cancer pain, adjunct medication such as ketamine and methadone and interventional therapies. We discuss neurolysis via injections, neuromodulation including targeted drug delivery and spinal cord stimulation, vertebral tumor ablation and augmentation, radiotherapy and surgical techniques. In the United States, there is a significant variance in the interventional treatment of cancer pain based on fellowship training. As a first of its kind, this best practices and interventional guideline will offer evidenced-based recommendations for reducing pain and suffering associated with malignancy.

Pain therapeutics from cone snail venoms: From Ziconotide to novel non-opioid pathways.

There have been numerous attempts to develop non-opioid drugs for severe pain, but the vast majority of these efforts have failed. A notable exception is Ziconotide (Prialt®), approved by the FDA in 2004. In this review, we summarize the present status of Ziconotide as a therapeutic drug and introduce a wider framework: the potential of venom peptides from cone snails as a resource providing a continuous pipeline for the discovery of non-opioid pain therapeutics. An auxiliary theme that we hope to develop is that these venoms, already a validated starting point for non-opioid drug leads, should also provide an opportunity for identifying novel molecular targets for future pain drugs. This review comprises several sections: the first focuses on Ziconotide as a therapeutic (including a historical retrospective and a clinical perspective); followed by sections on other promising Conus venom peptides that are either in clinical or pre-clinical development. We conclude with a discussion on why the outlook for discovery appears exceptionally promising. The combination of new technologies in diverse fields, including the development of novel high-content assays and revolutionary advancements in transcriptomics and proteomics, puts us at the cusp of providing a continuous pipeline of non-opioid drug innovations for pain. SIGNIFICANCE: The current opioid epidemic is the deadliest drug crisis in American history. Thus, this review on the discovery of non-opioid pain therapeutics and pathways from cone snail venoms is significant and timely.

Interventional Treatments of Cancer Pain.

Pain is a significant burden for patients with cancer and is particularly prevalent among those with advanced cancer. Appropriate interventional cancer pain therapies complement conventional pain management by reducing the need for systemic opioid therapy and its associated toxicity; however, these therapies are often underutilized. This article reviews techniques, indications, complications, and outcomes of the most common interventional approaches for the management of cancer-related pain. These approaches include intrathecal drug delivery, vertebral augmentation, neurolysis of the celiac, superior hypogastric and ganglion impar plexus', image-guided tumor ablation, and other less commonly performed but potentially beneficial interventions.

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.