The management of pain is an important component for the treatment of most patients with metastatic cancer. It is estimated that 5-15% of patients with metastatic cancer have pain that is refractory to oral and i.v. narcotics. Intraspinal implantable drug delivery systems (IDDSs) deliver small doses of morphine directly to the spinal fluid, theoretically requiring smaller doses of narcotics. Although this system is known to be effective, there have been no randomized controlled trials. Researchers in the U.S. and Europe affiliated with the Implantable Drug Delivery Systems Study Group have determined that IDDSs are better than conventional pain management techniques. They reported these results in the October 2002 issue of the Journal of Clinical Oncology.

These researchers randomly allocated 202 patients with refractory pain to receive treatment with IDDSs or comprehensive medical management. Clinical success in this study was defined as 20% or greater reduction in pain scores or a 20% or more reduction in toxicity. Eighty-five percent of patients receiving IDDS patients achieved clinical success, compared to 71% in the control group. There were more patients in the IDDS group who achieved both pain reduction and toxicity reduction. Patients in the IDDS group had significant reductions in fatigue and were more alert. In addition, IDDS patients had a 53.9% survival at 6 months, compared with 37.2% of the control group (P = .06). These authors concluded that IDDSs improved pain control and possibly improved survival in patients with refractory cancer pain. Complications associated with the IDDS were not significant and only one pump required removal.

Comments: This study points out the importance of aggressive pain control in patients with metastatic cancer. The improvement in survival is intriguing and needs to be confirmed.

Reference: Smith TJ, Staats PS, Deer T, et al. Randomized clinical trial of an implantable drug delivery system compared with comprehensive medical management for refractory cancer pain: impact on pain, drug-related toxicity, and survival. Journal of Clinical Oncology. 2002;20: 4040-4049.