Intrathecal Drug Delivery Systems for Cancer Pain: A Health Technology Assessment.

Abstract

Background: Pain is a common and very distressing symptom for adults and children with cancer. Compared with other routes of delivery, infusing pain medication directly into the intrathecal space around the spinal cord may reduce the incidence of systemic side effects and allow for more rapid and effective pain relief. We conducted a health technology assessment of intrathecal drug delivery systems (IDDSs) for adults and children with cancer pain, which included an evaluation of effectiveness, safety, cost-effectiveness, the budget impact of publicly funding IDDSs, patient preferences and values, and ethical considerations.

Methods: We performed a systematic literature search of the clinical evidence to retrieve systematic reviews, and we selected and reported results from 2 recent reviews that were relevant to our research questions. We complemented the chosen systematic reviews with a literature search to identify primary studies published after December 2020. We used the Risk of Bias in Systematic Reviews (ROBIS) tool to assess the risk of bias of each included systematic review. We assessed the quality of the body of evidence according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted a cost-effectiveness analysis comparing IDDSs with standard care (i.e., non-IDDS methods of pain management) from a public payer perspective. We also analyzed the budget impact of publicly funding IDDSs in Ontario. To contextualize the potential value of IDDSs, we spoke with patients with cancer pain and with caregivers of patients with cancer pain. We explored ethical considerations from a review of published literature on the use of IDDSs for the management of cancer pain in adults and children as well as a review of the other components of this health technology assessment to identify ethical considerations relevant to the Ontario context.

Results: We included 2 systematic reviews (1 on adults and 1 on children) in the clinical evidence review. In adults with cancer pain who have a life expectancy greater than 6 months, intrathecal drug delivery was associated with a significant reduction in pain intensity compared with before implantation up to a 1-year follow-up (GRADE: Moderate to Low). Improved pain management appeared to be maintained beyond a 4-week follow-up. IDDSs likely decrease the use of systemic opioids (GRADE: Moderate to Low). They may also improve health-related quality of life (GRADE: Low), functional outcomes (GRADE: Low), and survival (GRADE: Low to Very low). In children with cancer pain, IDDSs may reduce pain intensity, improve functional outcomes, and improve survival, but the evidence is very uncertain (all GRADEs: Very low). IDDS implantation carries certain rare risks related to mechanical errors, drug-related side effects, and surgical complications. There are inherent limitations in conducting research in patients with refractory cancer pain; therefore, it is unlikely that higher-quality evidence will emerge in the next few years. Our primary economic evaluation found that IDDSs are more effective and more costly than standard care. The incremental cost-effectiveness ratio of IDDSs compared with standard care is $57,314 per quality-adjusted life-year (QALY) gained. The probability of IDDSs being cost-effective versus standard care is 43.46% at a willingness-to-pay of $50,000 per QALY gained and 72.54% at a willingness-to-pay of $100,000 per QALY gained. Publicly funding IDDSs in Ontario would cost an additional $0.27 million per year, for a total of $1.34 million over the next 5 years. The patients with cancer pain and caregivers with whom we spoke described the debilitating nature of cancer pain and the difficulty of finding effective pain management options. Patients with experience of an IDDS spoke of its effectiveness and its positive impact on their quality of life and mental health. Implementing IDDSs for patients with cancer pain raises several ethical and equity considerations related to the experiences and management of cancer pain, how limitations in evidence may entail uncertainties in clinical and health system decision-making, as well as clinical, geographic, and health system access barriers.

Conclusions: Intrathecal drug delivery likely reduces pain intensity and decreases the use of systemic opioids in adults with cancer pain who have a life expectancy greater than 6 months. It may also improve health-related quality of life, functional outcomes, and survival, although the evidence for survival is very uncertain. The clinical evidence in children with cancer pain is very uncertain. IDDS implantation is reasonably safe. Intrathecal drug delivery is more effective and more costly than standard care. We estimate that funding IDDSs in Ontario will result in additional costs of $0.27 million per year, for a total of $1.34 million over the next 5 years. Considerations related to funding and implementing IDDSs for patients with cancer pain in Ontario will require explicit and focused attention to considerations of equity and access in the diagnosis and management of cancer pain and in the use, clinical uptake, and delivery of IDDS pain management.