Treatment of cancer-related pain: when orally administered medications fail.

OBJECTIVE: To summarize the available pain-relieving interventions other than oral medications for cancer-related pain.
DESIGN: The pertinent literature is reviewed, and the various options for treating pain in patients with cancer are discussed.
MATERIAL AND METHODS: The appropriate situations for use of parenteral administration of opioids, spinal analgesia, neural blockade, and neurosurgical treatment are outlined, and the potential problems and complications associated with these techniques are described.
RESULTS: The basic approach to the management of pain in patients with cancer is to begin treatment with less potent analgesic agents early and to progress toward use of more potent pharmaceutical agents, adjuvant drugs, and invasive procedures as needed for alleviation of pain. With parenteral administration of opioids, the dosage can be adjusted rapidly, and therapy can be continued even though a patient may have gastrointestinal dysfunction. A portable ambulatory infusion pump can be used in selected patients. The major advantage of spinal opioid analgesia is the intense analgesia provided with minimal side effects. The potential complications and the availability of treatment alternatives have limited the use of neurolytic blocks, which usually provide only temporary relief of pain. In carefully selected patients with pancreatic or other upper gastrointestinal neoplasms, however, neurolytic celiac plexus and splanchnic nerve blocks are effective. Patients who fail to respond to conservative interventions may be candidates for neurosurgical procedures, such as spinal cord, cortical, or brain-stem stimulation or neuroablative operations (most commonly, cordotomy).
CONCLUSION: Cancer-related pain continues to be a major problem, and clinicians should be aware of the availability of effective treatment strategies and techniques. When orally administered medications fail to control pain or cause excessive side effects, patients should be referred to an appropriate specialist or medical center for consideration of other pain-relieving techniques.