Terminally Ill Cancer Patients Often Fail to Seek Pain Relief

BETHESDA, Maryland—In a survey of terminally ill patients (half of them with cancer), only about one third of those with moderate to severe pain had requested more therapy from their physician during the previous month.

The findings suggest that cancer pain at the end of life may be due less to undertreatment than to patients’ fears of addiction and dislike of opioid side effects, said Ezekiel Emanuel, MD, of the National Institutes of Health, and his colleagues.

The researchers interviewed 988 terminally ill patients from six randomly selected US sites. Half of these patients reported moderate or severe pain, and 712 (72%) said they had seen a primary care physician or pain specialist in the last 4 weeks.

Of those patients who had seen a health care professional in the last 4 weeks, 29% said they wanted more pain therapy, 62% wanted their pain therapy to remain the same, and 9% wanted to reduce or stop their pain therapy (Lancet 357:1311-1315, 2001). Type of disease did not affect the desire for more treatment, Dr. Emanuel said.

The patients offered a number of reasons for not seeking additional pain therapy: fear of addiction, dislike of the physical side effects of pain medications such as constipation, dislike of the mental side effects of medication such as mental confusion, and not wanting to take more pills or injections.

The study showed that ethnic minorities had more pain and were more likely than whites to receive inadequate medication for their pain. Ethnic minority patients were also significantly more likely than whites to refuse additional pain medication because of fear of addiction. "Thus, ethnic minority patients might not be receiving acceptable doses of opioid analgesia because of the sociological stigma attached to these drugs," Dr. Emanuel said.

He concluded that "the number of terminally ill patients in substantial pain is too high, but the number is not as large as perceived. We found that most patients were willing to tolerate pain, even when substantial."

Other factors were more important to patients than pain relief, he said. Although the treatment of pain is important, he noted, "the prevalence of pain itself might not be the best outcome measure for the assessment of the quality of end-of-life care."

Dr. Emanuel and his co-authors stressed that physicians need to be trained in pain assessment and management, including the side effects of opioids. "Additionally, the development of pain treatments that do not produce the common side effects of opioids should be a high research priority," he said.

The researchers also indicated that physicians need to communicate more effectively with their patients, especially minority patients, that "addiction to opioids for pain relief is a myth."

Commentary

In a commentary, Sam Hjelmeland Ahmedzai, MD, of the Academic Palliative Medicine Unit, University of Sheffield, UK, said that the patients in the study seemed to be "collectively ill-informed about pain, prejudiced possibly by bad experiences, and inadequately cared for by their physicians."

Dr. Ahmedzai noted that although opioid addiction is rare in terminally ill patients prescribed opioids for pain control, "tolerance does develop, but hardly ever to the extent that modern potent opioids lose their effectiveness."

He noted that drugs such as morphine with low intrinsic opioid receptor affinity are more likely to induce tolerance than those with high intrinsic receptor efficacy such as fentanyl.

Gastrointestinal side effects of opioids and nonsteroidal anti-inflammatory drugs (NSAIDs), he said, "may be sufficient to turn patients away from the potential benefits of these agents." He noted that animal studies have shown that "drugs with a high penetration into the central nervous system because of lipophilicity, such as fentanyl, are less likely to cause constipation . . . than drugs such as morphine that do not penetrate centrally so well."

Finally, Dr. Ahmedzai pointed out that oxycodone may have an advantage over morphine in terms of sedation and cognitive impairment. Another strategy to reduce sedation is the concurrent use of psychostimulants such as methylphenidate with opioids, he said, adding that "physicians are inexplicably resistant to this approach, especially in Europe."

Dr. Emanuel’s study co-authors were Stefan Weiss, MHS, of the NIH; Linda Emanuel, MD, of Northwestern University School of Medicine; and Diane Fairclough, DPH, of the AMC Cancer Research Center, Denver.