Treating Pain in Patients with Cancer: Considerations When Prescribing Opioids
There are key factors to consider when determining the best treatment strategy for pain in patients with cancer.
Adequate pain control for patients with cancer can be extremely challenging, especially in those patients receiving chemotherapy or radiation therapy and/or in patients with end-stage disease.
Opioids represent one of the most commonly used medication classes used to treat patients with cancer. Many physicians use opioids as a first-line therapy for patients experiencing moderate to severe pain as opioids come in a multitude of doses, formulations and potency.
Up to 50% of patients receiving chemotherapy and 90% of patients with end-stage disease will require opioids.1
Despite the availability of opioids, pain is frequently undertreated in patient with cancer. A systematic review conducted by Greco and colleagues reported that up to 32% of patients with cancer were undertreated.2
This percentage had decreased from 43.4% in a prior review, however the review reinforced that undertreated pain is still a significant issue in the cancer population.2
Patients with cancer may be undertreated for pain for a variety of reasons, one of which includes the potential for opioid dependence.
Many people involved in the care of the patient can express concerns for developing opioid dependence including the physician, family and the patient themselves.
Unfortunately, there can be some confusion regarding the terminology used when describing certain syndromes associated with opioid use.
Based on their pharmacological properties, opioids if used enough, will ultimately lead to some form of dependence or tolerance.
Dependence refers to the physical withdrawal symptoms encountered by the patient when the medication is suddenly stopped or dose-reduced. Opioid withdrawal symptoms can include nausea, vomiting, diarrhea, sweating, anxiety, agitation, abdominal pain and insomnia.
Tolerance refers to the loss of drug effect over time, which often leads to the need to increase the dosage of opioid. There are several pathophysiological mechanisms to explain tolerance, however down-regulation of the opioid-receptors is a common explanation.
“Abuse” refers to the misuse of the opioid that differs from traditional medical and legal standards. “Addiction” is characterized by opioid cravings, inability to control the use of the medication and continued use of the opioid despite detrimental effects.3
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There are numerous questionnaires and scales to assess the patient's potential risk for negative drug behavior, however many of them have not been studied or validated in the cancer population.3,4
Answering yes to any of the three following statements places the patient at a higher risk for drug-related problems: presence of a major psychiatric condition, personal history of drug or alcohol abuse and family history of alcohol or drug abuse 3,4
Health care professionals should consider asking the patient these questions prior to initiating opioids.
When the physician or patient are struggling with the idea of opioid dependence, there are several potential opioid-sparing strategies that may prove useful.