Guidelines for Interventional Pain Management of Cancer Pain

A distinguished panel of pain management clinicians recently released consensus guidelines intended to “assist clinicians in identifying the candidacy of patients with cancer-related pain and end of life diseases causing pain that may benefit from intrathecal drug delivery.”

Noting that clinical trials have shown that “intrathecal drug delivery is a viable treatment strategy for both neuropathic and nociceptive pain in the cancer population” that can produce “improved pain relief and decreased adverse effects… compared with conventional medical management alone,” the authors of these guidelines caution readers that “Proper patient selection, implantation technique, maintenance, and continued vigilance are paramount to reduce predictable iatrogenic complications and ensure success” when using intrathecal (IT) drug delivery systems to treat patients for pain. To help guide physicians in making the proper assessments and IT drug treatment choices for patients suffering from cancer-related pain, an expert panel evaluated the available data supporting various measures and interventions and created these guidelines, supported by explanations of the evidence backing their recommendations for “clinically relevant management decisions.”

Regarding the prevalence, impact, and need for better treatment for cancer- and non-cancer related pain, the authors reported:

• The prevalence of pain in patients with early cancer disease may be as high as 30-40%; as high as 70-90% in patients with advanced disease
• Nearly two-thirds of patients with advanced incurable cancer may suffer from pain; one-third of these patients may suffer severe pain
• Non-cancer pain is “highly prevalent and increasing” in patients who also suffer from cancer-related pain
• Nearly two-thirds of patients may experience breakthrough cancer pain

IT drug therapy can “effectively reduce neuropathic and mixed neuropathic-nociceptive pain in cancer patients, while relieving drug-related toxicities and minimizing the need for supplementary systemic opioids.” Adverse effects associated with IT drug therapy include “opioid-induced hyperalgesia, hypotension, sedation, respiratory depression, inflammatory mass, hypogonadotropic hypogonadism, and immunologic compromise.” Other dangers associated with this approach to pain management include increased mortality risk from rapid and improperly monitored dose escalation. To guard against adverse events, the panel recommended that “therapy be initiated at low doses, with slow titration upward, as necessary, based on patient response.”

Recommendations for selecting patients for treatment with IT drug therapy include:

• Clinicians should consider the intensity of the patient’s pain and use “objective and subjective quality of life measures” when initiating and titrating therapy
• Patients with intractable cancer-related pain should be treated with a stepped approach, “beginning with the most conservative therapeutic options and progressing to more aggressive regimens when analgesia is inadequate or adverse effects are intolerable”
• There is no reliable evidence confirming “a direct association between a patient’s response to oral opioids and ensuing response to IT therapy”
• In patients undergoing chemotherapy, a white blood cell count ≤ 2 x 109/L and/or an absolute neutrophil count ≤ 1,000/μL may constitute a contraindication for implantation of an IT device -- patients with a white blood cell count ≤ 1.5 x 109/L can be considered for the procedure “provided they are receiving growth factor treatment”
• Althoguh IT therapy ‘is a useful strategy for immunocompromised patients,” the panel recommends “mitigation of infection reduction during trialing and implantation” and careful titration and medication selection
• Patients who display systemic signs of infection should not receive IT drug therapy
• When using anticoagulant and antiplatelet agents, clinicians should follow the American Society of Regional Anesthesia and Pain Medicine guidelines

Because it “may be difficult to overstate” the role played by psychological factors and emotional stresses in patients’ response to pain and pain treatment, clinicians should consider conducting a pre-implantation psychological evaluation of patients suffering with cancer-related pain based on the status of the patient’s disease. The authors identify three levels of need:

• Patients whose “life expectancy is significantly compromised” and for whom therapy is primarily designed for palliation -- pretrial/internalization psychological evaluation is optional
• Patients whose disease process “has been arrested, but wherein there is a significant probability of recurrence” -- psychological evaluation is encouraged, “with an emphasis on periodic psychological consultation/intervention to assist with changes in disease process/recurrence and coping”
• Patients who have been cured but are suffering residual chronic pain secondary to treatment - psychological evaluation is recommended, “in much the same way as those with chronic noncancer pain”

Although IT drug therapy trials prior to permanent device implantation can be used to “determine patient response to therapy and establish a baseline measurement from which potential improvement can be assessed,” research has not yet established “a direct correlation between a patient’s response during an IT trial and subsequent effects of therapy.” Thus, the panel reminds that “it is up to the implanting clinician to weigh the benefits and limitations of each trialing method and decide which technique—if any—is best suited for the patient.” The panel also recommends against the use of mandatory IT drug trials, especially for patients near the end of life.

In the conclusion to these recommendations, the authors wrote that although there has been “relatively limited application of this treatment modality,” IT therapy can “significantly help cancer patients with severe pain.” The authors recommend that clinicians seeking to optimize outcomes with IT drug therapy should ensure “careful consideration of the patient’s medical comorbidities and prior therapies, communication with the oncologist, proper psychological evaluation, and appropriate trialing technique.”

The complete text of “Comprehensive Consensus Based Guidelines on Intrathecal Drug Delivery Systems in the Treatment of Pain Caused by Cancer Pain,” published in the May/June 2011 issue of Pain Physician, is available online.