Implanted intrathecal drug delivery systems may be associated with improved survival in patients with cancer

Intrathecal Drug Delivery Systems (IDDS) are underused in the management of cancer-related pain despite evidence of both efficacy and survival benefit. There is currently limited evidence to indicate which patients might benefit most from IDDS.

The aim of the study was to describe the baseline characteristics and survival outcomes of patients who accepted IDDS, patients who declined IDDS and patients who wished to go ahead with IDDS but whose condition deteriorated before they could do so.

The survival data for 75 consecutive patients who had been offered intrathecal drug delivery were examined as part of a retrospective cohort study. Survival data was compared between three groups: those who accepted intrathecal drug delivery and went on to receive it (n = 41), those who accepted it but whose condition deteriorated before it commenced (n = 17) and those who declined this treatment modality (n = 17).

Patients who received IDDS survived significantly longer after assessment compared to those who declined IDDS (hazard ratio (HR) for the IDDS group relative to the declined group 0.29 (95% CI 0.16 to 0.53), and 0.23 (95% CI 0.12 to 0.44) after adjustment for gender and baseline functional status. In patients who accepted IDDS but who were unable to commence treatment, survival after assessment was not significantly different from those who declined the IDDS (HR for the deteriorated group relative to the declined group 1.28 (95% CI 0.65 to 2.53), and 0.80 (95% CI 0.65 to 2.53) after adjustment for gender and baseline functional status).

In this retrospective analysis, an improvement in survival may be associated with patients who accept ongoing pain management with an implanted intrathecal drug delivery system compared to those patients who either declined intrathecal drug delivery or deteriorated before it could be commenced.