Optimizing Initial Intrathecal Drug Ratio for Refractory Cancer-Related Pain for Early Pain Relief. A Retrospective Monocentric Study

Abstract

Objective Intrathecal (IT) drug delivery has shown its efficiency in treating refractory cancer pain, but switching opioids from the systemic to the intrathecal route is a challenging phase. Moreover, associations are widely used and recommended. Few data deal with the initial dosage of each drug. Analyzing conversion factors and initial dosages used in intrathecal therapy seems essential to decreasing the length of titration and to delivering quick pain relief to patients. Methods We retrospectively analyzed data from consecutive adult patients implanted with an intrathecal device for cancer pain and treated at the Institut de Cancérologie de l’Ouest, in Angers, France, for four years. The main goal was to identify factors associated with early pain relief after intrathecal drug delivery system (IDDS) implantation. Results Of the 220 IDDS-treated patients, 70 (32%) experienced early pain relief (EaPR) and 150 (68%) delayed pain relief (DePR). Performance Status stage and initial IT ropivacaine:IT morphine ratio were the variables independently associated with EaPR. The best IT ropivacaine:IT morphine ratio to predict EaPR was 5:1, with a 73% (95% confidence interval [CI] = 64.8% to 79.6%) sensitivity and a 67.1% (95% CI = 54.9% to 77.9%) specificity. EaPR subjects experienced better pain relief (–84% vs –60% from baseline pain score, P < 0.0001), shorter length of hospitalization (7 vs 10 days, P < 0.0001), and longer survival (155 vs 82 days, P = 0.004). Conclusions Local anesthetic:morphine ratio should be considered when starting IDDS treatment. EaPR during the IT analgesia titration phase was associated with better pain relief and outcomes in patients with refractory cancer-related pain.

Pancreas Cancer-Associated Pain Management

“…An observational study designed to evaluate the 11‐year results (2006–2017) of IDDSs for refractory pancreas cancer pain [91, 92] demonstrated that IDDS‐treated patients experienced 50%–75% reductions in mean pain levels. Ropivacaine was usually added as a first‐ or second‐line therapy.…”

Initial Intrathecal Dose Titration and Predictors of Early Dose Escalation in Patients With Cancer Using a 100:1 Oral to Intrathecal Morphine Conversion Ratio

“…Recently Dupoiron et al retrospectively reviewed 220 cancer patients on IDD and their initial intrathecal dosing with a focus on the relative efficacy of different ratios of local anesthetic and opioid. The authors estimated an OME to IME ratio closer to 250:1 but in the setting of a more progressive local anesthetic dosing protocol and a quite prolonged inpatient titration phase (24). In 2007, Mercadante et al reported the use of the 100:1 oral-to-intrathecal ratio in 55 cancer patients using externalized intrathecal catheters to syringe or bulb pumps.…”

Initiation of Intrathecal Drug Delivery Dramatically Reduces Systemic Opioid Use in Patients With Advanced Cancer

“…Another recent study attempted to determine optimal initial dosing strategies for refractory cancer‐related pain by retrospectively comparing 220 patients experiencing early versus late pain relief following implantation of IDDS. The authors report differences in systemic opioid doses on the day of implantation between different groups but do not report overall change in systemic opioid dose despite looking for measures of success between the two groups including rate of 50% NRS decrease between days 0 and 7, length of hospital stay, and number of IT drug dose adjustments (27).…”