A total of 202 patients from 21 medical centers participated in the prospective, randomized clinical study. The main outcomes of the study were pain control and reduction in drug side effects. Researchers defined clinical success as at least a 20 percent reduction in visual analog scale pain scores or equal pain scores with a minimum of 20 percent reduction in toxicity.

At four weeks, the pain scores for patients assigned to treatment with the pump in addition to conventional pain therapy fell 52 percent compared with 39 percent for patients who received only conventional therapy. The pump group's composite drug-related toxicity scores dropped by 50 percent compared with 17 percent for the conventional therapy group. Importantly, researchers found statistically significant reductions in fatigue and sedation in patients assigned to the pump compared with patients receiving conventional therapy alone.

In addition, 54 percent of patients in the pump group were alive after six months of treatment compared with 37 percent in the conventional therapy group. Although survival was not a planned study outcome, the finding is of great interest and the authors believe it is enough to warrant further evaluation.

In the current study, complications with the infusion system were similar to those seen in typical clinical use. Because the drug pump is surgically placed, surgical complications such as infection are possible. The catheter could be dislodged or blocked, or in rare cases, the pump itself could stop working. Any of these events could cause a reduction in or loss of pain relief.

The Medtronic SynchroMed(r) EL Infusion System, the intrathecal drug delivery system used in the study, consists of a programmable pump and a catheter that are implanted during an hour-long surgical procedure. The pump is placed just under the skin of the abdomen and is connected to a small, flexible catheter that delivers pain medication directly into the intrathecal space.

The results of the study -- the first trial comparing intrathecal infusion to comprehensive medical management for intractable cancer pain -- may lead to new treatment guidelines for physicians and renewed hope for patients and their families.

"As an oncologist, I've seen firsthand how a patient's pain can hamper our efforts to treat the cancer itself and adversely affect the entire family," said Dr. Thomas J. Smith, the study's oncology cochairman and the article's lead author. "By using the pump, we can deliver medication directly into the patient's spinal fluid, where small doses can have a big impact on pain. Put simply, less medication means fewer side effects, which makes life better not only for the patient but for the patient's family, too. And with the pain under control, we can focus on treating the cancer."

About one third of all people with cancer and two thirds of people with advanced disease experience significant pain, according to statistics provided by the American Cancer Society. However, up to 15 percent of these patients fail to get relief from oral opioid medications. For a subset of these patients -- approximately 50,000 Americans -- intrathecal pain therapy with a programmable drug pump represents a viable treatment option.

"Opioids such as morphine are extremely effective for treating severe pain," said cancer pain specialist Dr. Richard Boortz-Marx, a coauthor of the study. "Unfortunately, in high doses they can also cause sedation, clouded thinking, constipation and fatigue -- a constellation of side effects that lead many physicians to underprescribe these drugs and many patients to underuse them. With this study, we've shown that by altering how we deliver the medications, we can provide better pain relief, minimize the side effects, and perhaps even help patients to live longer."