Trialing Strategies Prior to Intrathecal Drug Delivery in Cancer-Related Pain: A Narrative Review

Purpose of ReviewCancer-related pain poses a significant clinical challenge, especially in advanced stages where systemic analgesic therapies become insufficient or intolerable. Intrathecal drug delivery systems (IDDS) offer targeted pain control while minimizing systemic exposure. However, the optimal trialing approach before permanent IDDS implantation remains contentious. This narrative review examines literature on IDDS trialing strategies in cancer pain management. A comprehensive search was conducted of PubMed, MEDLINE, and Embase databases and identified studies published up to January 2025. The review included prospective and retrospective studies, randomized controlled trials, cohort studies, and case series on trialing techniques, clinical outcomes, safety, tolerability, and efficacy. Key strateghies assessed include single-shot intrathecal bolus, multiple intrathecal boluses, continuous epidural infusion, and continuous intrathecal infusion. The review found significant variability in trialing practices, with limited high-quality comparative data to support standardized protocols. Trial success criteria varied widely, encompassing pain reduction, side effects, and patient-reported outcomes.Recent FindingsThe studies described a range of trialing strategies with varying durations, opioid dosages, and criteria for success. However, due to the lack of direct comparisons between these approaches, it is difficult to draw clear conclusions about the relative effectiveness of continuous intrathecal, continuous epidural, and bolus-based trials. Some institutions bypassed trialing, prioritizing symptom relief over procedural risks. Conclusion: This review highlights the need for individualized trialing strategies based on patient status, institutional preferences, and clinician expertise. Given the variability in current practices, further research is needed to establish evidence-based guidelines and optimize clinical decision-making.