Cancer pain: Overview

Abstract
Importance: There are no updated systematic reviews examining the prevalence of persistent pain among head and neck cancer survivors.

Objectives: This systematic review aims to identify the prevalence and characteristics of persistent pain across locations among head and neck cancer survivors.

Design: A systematic review and meta-analysis.

Participants: Head and neck cancer survivors with persistent pain.

Methods: It was conducted according to PRISMA guidelines on December 14th, 2023 (PROSPERO reference CRD42024494926). The MEDLINE via PubMed, Scopus, Web of Science, CINAHL, Ovid and Cochrane Library databases were searched. Studies had to report prevalence data on persistent pain in head and neck cancer survivors who completed cancer treatment at least 3 months ago. Quality of the included studies was assessed using the critical appraisal tool developed by the Joanna Briggs Institute. Statistical heterogeneity was assessed prior to perform the meta-analysis using τ2, I2, and Q. Univariate meta-regression analyses were used to examine sources of heterogeneity.

Results: 1713 records were retrieved. After removing duplicates 1385 articles were screened. Ultimately, 182 articles were assessed for full-text screening, of which 17 manuscripts were included for review. The prevalence of the studies was 31% (95% CI, 20 to 42). The meta-regression explained approximately 40% of the observed heterogeneity (R2 = 40.57).

Conclusions: This systematic review highlights that almost third of head and neck cancer survivors are under persistent pain after finishing cancer treatment. No final conclusions can be drawn as to which extent cancer location, cancer treatment, pain measurement method and timing of pain assessments could modify this prevalence. Results should be interpreted with caution since there is considerable variability in the methods.

Abstract
Background: This paper presents a collection of important topics that are not related to the other Focus papers in this AJGP issue on palliative care but are nevertheless important for clinical practice.

Objective: This article reviews the safe use of fentanyl, the proper use of buprenorphine and oxycodone-naloxone, and the potential pitfalls of equianalgesic tables.

Discussion: Sublingual and transdermal fentanyl are contraindicated in patients who are opioid-naïve. Opioid-naïve has a strict definition. Buprenorphine does not reduce the efficacy of other analgesics. Equianalgesic tables should not be followed blindly - they have many shortcomings, even if they are the best guidance we have. The benefit of combined oxycodone-naloxone products is modest in patients receiving palliative care in whom there is a higher risk of therapeutic failure and adverse effects. In summary, these are clinical topics that frequently arise when specialist input is sought but are not directly addressed in most clinical articles.

Abstract
Objective: To systematically evaluate the clinical practice guidelines for cancer pain management published during 2014-2024, analyze the quality characteristics and recommendations of existing guidelines, and provide an evidence-based basis for the development and implementation of standardized clinical practice guidelines for pain management.

Methods: A systematic search of PubMed, OVID, Cochrane Library, China National Knowledge, and other databases was performed to include guidelines related to the management of cancer pain patients. The Appraisal of Guidelines for Research and Evaluation Tool (AGREE II) was used to evaluate the quality of the literature that met the inclusion criteria and to determine the guideline recommendation level.

Results: A total of 23 guidelines were included. AGREE II evaluation results demonstrated that the average scores across six domains were as follows: scope and purpose (97.22%), participants involved in guideline development (73.67%), rigor of development (70.32%), clarity (85.51%), applicability (39.22%), and independence of compilation (81.16%). There were 4 grade A recommendations, 19 grade B recommendations, and no grade C guidelines. The guideline recommendations primarily encompassed five core areas: cancer pain diagnosis, management of special populations, principles of pain management, intervention measures, and pharmaceutical services.

Conclusions: Existing clinical practice guidelines for cancer pain management are generally of high quality, but there is still much room for improvement in terms of applicability. It is recommended to optimize the development, dissemination, and application of the guidelines, taking into full consideration the individualized characteristics of patients, in order to further improve the quality of clinical practice in cancer pain management.