Background: A randomized clinical trial of implantable drug delivery system (IDDS) plus comprehensive medical management (CMM) versus CMM alone in 200 patients with refractory cancer pain showed better clinical success with IDDS. The objective of this study was to evaluate whether IDDS could help the most refractory patients failed by expert CMM.
Patients and methods: This was a planned longitudinal prospective analysis of 30 of 99 (30%) patients for whom CMM failed who crossed over to IDDS by 6 months, as part of the randomized clinical trial. Patients had a pain visual analogue scale (VAS) score of 5 or more despite CMM with 320 mg or morphine-equivalent opioids and adjunct drugs for 1 month. The intervention was an implantable intrathecal programmable pump with opioids and local anesthetics. Clinical success was measured as a 20% change in pain VAS score and NCI CTEP drug toxicity scales.
Results: Clinical success was achieved with pain scores and drug toxicity scores significantly reduced by 27% (p = 0.011) and 51% (p < 0.0001). Median survival was 103 days after IDDS implant, similar to IDDS patients who received implantation as part of the initial randomization.
Conclusions: CMM patients who crossed over to IDDS for the most refractory pain had significant reductions in pain and drug toxicity. The survival time of 3 months may be long enough for the IDDS implant to be cost effective. In this prospective longitudinal study, patients with refractory cancer pain despite comprehensive medical management derived benefit from IDDS.