Neurosurgery in the treatment of cancer pain

JNJ-20788560 [9-(8-azabicyclo[3.2.1]oct-3-ylidene)-9H-xanthene-3-carboxylic acid diethylamide], a selective delta opioid receptor agonist, is a potent and efficacious antihyperalgesic agent that does not produce respiratory depression, pharmacologic tolerance, or physical dependence

Mu-opioid analgesics are a mainstay in the treatment of acute and chronic pain of multiple origins, but their side effects, such as constipation, respiratory depression, and abuse liability, adversely affect patients. The recent demonstration of the up-regulation and membrane targeting of the delta-opioid receptor (DOR) following inflammation and the consequent enhanced therapeutic effect of delta-opioid agonists have enlivened the search for delta-opioid analgesic agents. JNJ-20788560 [9-(8-azabicyclo-[3.2.1]oct-3-ylidene)-9H-xanthene-3-carboxylic acid diethylamide] had an affinity of 2.0 nM for DOR (rat brain cortex binding assay) and a naltrindole sensitive DOR potency of 5.6 nM (5'-O-(3-[(35)S]thio)triphosphate assay). The compound had a potency of 7.6 mg/kg p.o. in a rat zymosan radiant heat test and of 13.5 mg/kg p.o. in a rat Complete Freund's adjuvant RH test but was virtually inactive in an uninflamed radiant heat test. In limited studies, tolerance was not observed to the antihyperalgesic or antinociceptive effects of the compound. Unlike ibuprofen, JNJ-20788560 did not produce gastrointestinal (GI) erosion. Although morphine reduced GI motility at all doses tested and reached nearly full effect at the highest dose, JNJ-20788560 did not retard transit at the lowest dose and reached only 11% reduction at the highest dose administered. Unlike morphine, JNJ-20788560 did not exhibit respiratory depression (blood gas analysis), and no withdrawal signs were precipitated by the administration of opioid (mu or delta) antagonists. Coupled with the previously published lack of self-administration behavior of the compound by alfentanil-trained primates, these findings strongly recommend delta-opioid agonists such as JNJ-20788560 for the relief of inflammatory hyperalgesia.

Is there still a role for open cordotomy in cancer pain management?

For a small number of cancer patients, good pain control remains difficult to achieve despite adequate assessment and medical management. In nine cases, effective control of intractable pain from malignant pelvic disease was achieved by open thoracic cordotomy. The technique was well tolerated, with no major complications. Eight of the nine patients decreased their median daily oral morphine requirement from 560 mg (range 360-2600 mg) to 160 mg (range 40-1000 mg). Maximal survival time post-cordotomy was 830 days, with a median of 107 days. No patient experienced recurrent pain in the initially painful site. For patients with intractable pain associated with advanced pelvic malignancy, the use of an open cordotomy should be considered when satisfactory pain control is not achieved by medical or minimally invasive methods.

Intraventricular administration of morphine for control of intractable cancer pain in 90 patients

OBJECTIVE

To quantitate the relief of intractable cancer pain by the use of intraventricular morphine administration.

METHODS

Intraventricular morphine administration was performed through an Ommaya reservoir. An initial dose of 0.25 mg of morphine sulfate per 24 hours was administered to all of the patients. This dose was progressively increased in 0.25-mg increments until optimal analgesia was attained.

RESULTS

Sixty men and 30 women with a median age of 58 years (range, 23-80 yr) entered the study. The median duration of pain was 6 months (range, 0.5-120 mo). A daily morphine dose of up to 1 mg was adequate to achieve an analgesic effect in 77% of the patients. Only nine patients (10%) achieved < 50% pain relief. Using a multiple regression analysis, only the morphine dosage was found to be an independent prognostic factor. The most frequent side effect (22%) was nausea/vomiting. Also, there were two patients with opioid intolerance and two with intracerebral hematomas. Three reservoirs failed.

CONCLUSION

Intraventricular morphine administration is a useful method for palliation of intractable cancer pain.

Commissural myelotomy for intractable cancer pain: report of two cases

PATIENTS

We describe two patients with cancer-related low back and bilateral lower extremity pain that failed pharmacologic treatment.

RESULTS

In both cases, commissural myelotomy provided significant pain relief. The role of myelotomy in the management of cancer pain is discussed.

CT-guided pain procedures for intractable pain in malignancy

CT-guided stereotactic percutaneous destructive procedures, i.e. percutaneous cordotomy, trigeminal tractotomy, and extralemniscal myelotomy, have been routinely used for the treatment of localized intractable pain in malignancy since 1987. In 67 cases if local pain due to malignancy, CT guided percutaneous cordotomy was performed and in 97% complete pain control was achieved. In 45 of these cases, a "selective cordotomy" was performed meaning that analgesia was produced only in the painful region of the body. CT guided trigeminal tractotomy was applied to a total of 19 cases in 5 of which pain had been caused by malignancy. The results were satisfactory. 12 cases, suffering from visceral pain due to malignancy, were treated by CT-guided extralemniscal myelotomy and in 10 cases pain relief was achieved.

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.

Pathophysiology of pain

OBJECTIVE

To review the pain pathways in the central and peripheral nervous system and the actions of drugs used to treat pain.

DESIGN

An overview of pain pathways is presented, beginning in the periphery and progressing centrally, and the ascending and descending pathways are described in detail.

RESULTS

The nociceptive pathway, consisting of the classic three-neuron chain, is now understood to be a dual system at each level, and the sensation of pain is thought to arrive in the central nervous system with the discriminative component of pain ("first pain") carried separately from the affective-motivational component of pain ("second pain"). In addition to spinal control mechanisms of nociceptive transmission, descending pathways that originate in three major areas--the cortex, thalamus, and brain stem--can modify functions at the spinal level. At every level of the nervous system, a close relationship prevails between somatic pain pathways and visceral pathways. This relationship likely accounts for the transmission of visceral pain and also for autonomic responses to somatic pain and somatic responses to visceral pain.

CONCLUSION

By understanding the pathways of pain and the transmitters involved, prevention and treatment of pain will be improved.

Management of orofacial pain in cancer patients

Pain in patients with cancer may arise due to the primary disease, or due to therapy of the malignant disease. Pain may be caused by oral infection, oral mucositis, and by alteration in musculoskeletal and neurological function. The management of orofacial and oropharyngeal pain in patients with cancer is reviewed in this paper.