Palliative analgesia with topical sevoflurane in cancer-related skin ulcers: a case report

Pharmacogenetics of DPYD and treatment-related mortality on fluoropyrimidine chemotherapy for cancer patients: a meta-analysis and trial sequential analysis

BACKGROUND

Fluoropyrimidines are chemotherapy drugs utilized to treat a variety of solid tumors. These drugs predominantly rely on the enzyme dihydropyrimidine dehydrogenase (DPD), which is encoded by the DPYD gene, for their metabolism. Genetic mutations affecting this gene can cause DPYD deficiency, disrupting pyrimidine metabolism and increasing the risk of toxicity in cancer patients treated with 5-fluorouracil. The severity and type of toxic reactions are influenced by genetic and demographic factors and, in certain instances, can result in patient mortality. Among the more than 50 identified variants of DPYD, only a subset has clinical significance, leading to the production of enzymes that are either non-functional or impaired. The study aims to examine treatment-related mortality in cancer patients undergoing fluoropyrimidine chemotherapy, comparing those with and without DPD deficiency.

METHODS

The meta-analysis selected and evaluated 9685 studies from Pubmed, Cochrane, Embase and Web of Science databases. Only studies examining the main DPYD variants (DPYD*2A, DPYD p.D949V, DPYD*13 and DPYD HapB3) were included. Statistical Analysis was performed using R, version 4.2.3. Data were examined using the Mantel-Haenszel method and 95% CIs. Heterogeneity was assessed with I2 statistics.

RESULTS

There were 36 prospective and retrospective studies included, accounting for 16,005 patients. Most studies assessed colorectal cancer, representing 86.49% of patients. Other gastrointestinal cancers were evaluated by 11 studies, breast cancer by nine studies and head and neck cancers by five studies. Four DPYD variants were identified as predictors of severe fluoropyrimidines toxicity in literature review: DPYD*2A (rs3918290), DPYD p.D949V (rs67376798), DPYD*13 (rs55886062) and DPYD Hap23 (rs56038477). All 36 studies assessed the DPYD*2A variant, while 20 assessed DPYD p.D949V, 7 assessed DPYD*13, and 9 assessed DPYDHap23. Among the 587 patients who tested positive for at least one DPYD variant, 13 died from fluoropyrimidine toxicity. Conversely, in the non-carrier group there were 14 treatment-related deaths. Carriers of DPYD variants was found to be significantly correlated with treatment-related mortality (OR = 34.86, 95% CI 13.96-87.05; p < 0.05).

CONCLUSIONS

This study improves our comprehension of how the DPYD gene impacts cancer patients receiving fluoropyrimidine chemotherapy. Identifying mutations associated with dihydropyrimidine dehydrogenase deficiency may help predict the likelihood of serious side effects and fatalities. This knowledge can be applied to adjust medication doses before starting treatment, thus reducing the occurrence of these critical outcomes.

At-home Topical Sevoflurane Added to the Conventional Analgesic Treatment for Painful leg Ulcers Greatly Improved the Analgesic Effectiveness and Reduced Opioid Consumption in a Single-Center Retrospective Comparative Study with one-Year Follow-up

The general anesthetic sevoflurane is being repurposed as a topical analgesic for painful chronic wounds. This study was aimed to compare the analgesic effectiveness and safety of systemic analgesics alone or plus at-home topical sevoflurane for the management of patients with painful nonrevascularizable leg ulcers who were referred to a Pain Clinic by their attending vascular surgeons. We reviewed charts of patients treated in a single Pain Clinic with analgesic Standard of Care either alone (group SoC) or plus at-home topical sevoflurane (group SoC + Sevo), according to safety criteria. The area under the curve of pain over a year (AUC-Pain) was the primary outcome for analgesic effectiveness. Opioids were converted into Oral Morphine Milligram Equivalents. Groups SoC (n = 26) and SoC + Sevo (n = 38) were similar in baseline characteristics. Compared to SoC, median values [interquartile range] of area under the curve of pain for one-year follow-up were markedly lower for SoC + Sevo (54 [35-65] vs. 15 [11-23]; p < 0.000001, U Mann-Whitney test). Oral Morphine Milligram Equivalents were similar at baseline (SoC: 78.5 [22.5-135] vs. SoC + Sevo: 101.3 [30-160]; p = 0.753), but significantly lower for SoC + Sevo at three (120 [22.5-202.5] vs. 30 [0-80]; p = 0.005), six (120 [11.3-160] vs. 20 [0-67.5]; p = 0.004), nine (114.4 [0-154] vs. 0 [0-37]; p = 0.018), and 12 months (114.4 [0-154] vs. 0 [0-20]; p = 0.001). Multiple linear regression analysis revealed the addition of sevoflurane to be the most likely variable to explain this difference in outcome (ß:-33.408; p < 0.000001). Nine patients (24%) in SoC + Sevo had adverse effects attributed to sevoflurane, but only one patient needed to stop using sevoflurane due severe dermatitis. In conclusion, the addition of topical sevoflurane to the analgesic standard of care in patients with painful nonrevascularizable leg ulcers was a well-tolerated therapy that significantly improved pain control and allowed for a significant reduction in opioid consumption.

Scoping Review of Off-Label Topical Analgesia in Palliative, Hospice and Cancer Care: Towards Flexibility in Evidence-Based Medicine

PURPOSE

Scoping reviews address the nature of the literature per se rather than inferring evidence-based treatment guidelines. Scoping reviews of the published literature are intended to describe the aggregated nature of the evidence surrounding some agent or intervention, in contrast to systematic reviews that seek when possible to guide clinical practice. We conducted a scoping review to identify reports of potential clinical utility of off-label topical analgesics and adjuvants when FDA-approved treatments have proven inadequate.

METHODS

We performed a comprehensive search of three databases (PubMed, Web of Science and Embase) for articles dating from 1947 to the present. Mindful that FDA-approved and WHO-recommended analgesic medications often prove inadequate for individual patients in extremis with palliative, hospice or cancer pain, we used broad, structured inclusion criteria to retrieve articles.

RESULTS

We retrieved 12,100 articles; after screening, we had 39 reports addressing 19 different topical agents out of the 32 chemical entities. Our scoping review disclosed evidence about agents that might not have met inclusion criteria for clinical practice guidelines.

DISCUSSION

Although generally considered lower quality evidence, case reports or series present suggestions for diverse topical medications to manage pain in challenging circumstances when high-quality evidence for agents and routes of administration is lacking.

CONCLUSION

Patients with the greatest need for evidence to identify and guide lesser-used agents during aggressive pain management are the most difficult to enroll and follow in standardized, controlled and/or blinded clinical trials. This scoping review identifies medications, dosages, and routes of topical agents reported to be effective in these often-challenging circumstances. Until larger and higher quality studies are completed, we must rely on the best available evidence even if of lower quality.

Cost-effectiveness analysis of domiciliary topical sevoflurane for painful leg ulcers

Objectives

The general anesthetic sevoflurane is being repurposed as a topical analgesic for painful chronic wounds. We conducted a Bayesian cost-effectiveness analysis (CEA) comparing the addition of domiciliary topical sevoflurane to conventional analgesics (SEVOFLURANE, n = 38) versus conventional analgesics alone (CONVENTIONAL, n = 26) for the treatment of nonrevascularizable painful leg ulcers in an outpatient Pain Clinic of a Spanish tertiary hospital.

Methods

We used real-world data collected from charts to conduct this CEA from a public healthcare perspective and with a one-year time horizon. Costs of analgesics, visits and admissions were considered, expressed in €2016. Analgesic effectiveness was measured with SPID (Sum of Pain Intensity Difference). A Bayesian regression model was constructed, including “treatment” and baseline characteristics for patients (“arterial hypertension”) and ulcers (“duration”, “number”, “depth”, “pain”) as covariates. The findings were summarized as a cost-effectiveness plane and a cost-effectiveness acceptability curve. One-way sensitivity analyses, a re-analysis excluding those patients who died or suffered from leg amputation, and an extreme scenario analysis were conducted to reduce uncertainty.

Results

Compared to CONVENTIONAL, SEVOFLURANE was associated with a 46% reduction in costs, and the mean incremental effectiveness (28.15±3.70 effectiveness units) was favorable to SEVOFLURANE. The estimated probability for SEVOFLURANE being dominant was 99%. The regression model showed that costs were barely influenced by any covariate, whereas effectiveness was noticeably influenced by “treatment”. All sensitivity analyses showed the robustness of the model, even in the extreme scenario analysis against SEVOFLURANE.

Conclusions

SEVOFLURANE was dominant over CONVENTIONAL as it was less expensive and much more effective.

Sevoflurane topical analgesia for intractable pain with suicidal ideation

Proper symptom management to improve quality of dying is mandatory in palliative care patients. Home-based control of pain caused by leg ulcers is challenging, especially when the pain is severe and refractory to conventional analgesics, the patient is intolerant to opioids and refuses invasive measures. This was the case for an 87-year-old woman under oncological palliative care who suffered from a leg ulcer causing refractory pain, which produced suicidal ideation. Leg amputation was indicated, but she had signed a living will refusing any invasive measures. After obtaining written informed consent, sevoflurane was applied topically on the ulcer, which resulted in a rapid and long-lasting reduction of pain. Daily self-administration of sevoflurane successfully controlled the wound pain and the patient abandoned her suicidal ideation, the wound healed 35 days later, and her quality of dying improved remarkably. Topical sevoflurane deserves further research on ulcers of vascular and also neoplastic aetiology.

Pain reduction of topical sevoflurane vs intravenous opioids in pressure ulcers

Recently, it has been reported that topical irrigations of liquid sevoflurane on the bed of painful wounds produce a rapid, intense, and lasting analgesic effect. In this paper, A cohort of 112 patients with painful pressure ulcers who were refractory to opioids (or who exhibited undesirable adverse events to them) was treated with topical sevoflurane as per local institutional policy. These patients were recruited from an intensive care unit for a period of 3 years. The main aim was to determine the effectiveness of topical sevoflurane in reducing the pain of PUs and reducing the ulcer area. Study findings are reported and discussed herein and suggest that sevoflurane is a viable and promising treatment option for PUs.

Occupational exposure to sevoflurane following topical application to painful wounds

BACKGROUND

Occupational exposure to halogenated anesthetics employed for general anesthesia has been extensively studied. Conversely, a new modality of treatment of painful wounds with topical sevoflurane lacks exposure studies.

OBJECTIVES

To evaluate the magnitude of acute occupational exposure to sevoflurane following topical application to painful wounds.

METHODS

Four patients with chronic painful wounds were treated with topical sevoflurane (20, 20, 20 and 10 mL) following an approved therapeutic protocol in our Pain Management Unit. Eight passive dosimeters were placed at different locations of a treatment room with a volume of 163 m3 and 3.3 air changes per hour: 3 for near peak (for 20-50 min) and 1 overall exposure (for 3.4 h) at the nurse's breathing zone, and 4 for area exposure (for 3-3.4 h). Worst-case scenario theoretical concentrations of sevoflurane were also calculated.

RESULTS

The highest levels were obtained for two dosimeters worn by the nurse at the breathing zone (8.28 and 9.12 ppm-TWA [parts per million-Time-Weighted Average]), while the lowest level was obtained from the dosimeter placed on the most distant wall from patients (0.73 ppm-TWA). Theoretical concentrations were calculated from standard volatilization principles and were in agreement with the concentrations measured. Discussion-Conclusions: All air concentrations measured were lower than exposure limits set by occupational safety agencies from Finland, Sweden and Norway, which range from 10 ppm for a TWA of 8 hours to 20 ppm for short-term exposures (15 min). Application of topical sevoflurane on wounds seems to be environmentally safe for health-care professionals as it produces exposure levels lower than the established limits for anesthetic procedures.

Analgesic effectiveness of topical sevoflurane to perform sharp debridement of painful wounds

OBJECTIVE

Analgesic topical options to perform wound debridement are scarce. The purpose of this study was to communicate our experience using topical sevoflurane as analgesic for wound debridement.

METHODS

After approval by our institutional review board, medical records were reviewed for those patients who had previously accepted to be treated with off-label topical sevoflurane (1 mL/cm²) as an analgesic for sharp debridement of painful wounds, because it was previously approved by our institutional Pharmacy Regulatory Commission and Medical Management. According to this protocol, pain scores were measured by using a numerical rating scale (from 0 to 10 points) over a 10-hour period. Wound debridement was performed following routine procedures.

RESULTS

Medical records from 152 patients were reviewed. Baseline pain was severe (median, 7 points). After topical sevoflurane application, the analgesic effect was rapid (median pain score of 2 points at 5 minutes), and full debridement was feasible in most wounds (93%). The initial intense analgesic effect lasted for 30 minutes and then it subsided gradually over time to nearly reach baseline values after 10 hours. The patients estimated that the analgesic effect lasted several hours (median, 9 hours), and their overall satisfaction was high (median of 8 points on a scale ranging from 0 to 10). Fifty-two patients (34%) experienced itching.

CONCLUSIONS

Topical application of sevoflurane to painful wounds produced a rapid, robust, and long-lasting analgesic effect, which allowed for a high degree of wound debridement.