Study Raises Questions About Use of Opioids by Cancer Patients

By Pat Anson, PNN Editor

A new study led by researchers in Australia is raising questions about the effectiveness of prescription opioids in treating cancer pain, saying the evidence from clinical trials is inconclusive or “largely lacking.”

Opioids are a common treatment for cancer pain and are often considered indispensable, particularly near the end of life or in palliative care when pain can be most severe. Virtually all medical guidelines – including the CDC’s – specifically exempt cancer patients from any recommended limits on opioids.

But the new study, published in A Cancer Journal for Clinicians, rejects that long-held medical practice, suggesting that opioids work no better than a placebo in relieving cancer pain and that non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin may be just as good or better.

The study examined findings from over 150 clinical trials involving opioids and cancer, and found that most were not blinded or placebo-controlled. That’s a recurring issue in pain research due to the ethical issues involved in giving patients an ineffective or non-existent analgesic, particularly if they have a terminal illness. Although that shortcoming is widely understood and accepted – the authors of this new study view it as lack of evidence.

“Opioids are the most commonly used treatments for cancer pain management, and, although we might have assumed that there were placebo-controlled trials to support this widespread practice, our findings highlight that the evidence is largely lacking,” wrote lead author Christina Abdel Shaheed, PhD, Senior Academic Fellow at the University of Sydney School of Public Health, Faculty of Medicine and Health.

“There was an absence or paucity of placebo-controlled trials for some of the most commonly used opioid analgesics for cancer pain, including morphine, methadone, buprenorphine, fentanyl, hydromorphone, oxycodone, and tramadol.”

Ironically, Shaheed and her co-authors found that “weaker” opioids such as tapentadol and codeine may work better for cancer pain than the more potent opioids.

They also suggest that NSAIDs and antidepressants are more effective and have fewer side effects for someone with “background” cancer pain who is not nearing the end of life. In effect, they’re saying that opioids are only good if you’re dying.

“In practice, opioids are indispensable for intractable pain and distress at the end of life. What is worth highlighting is that non-opioids, particularly NSAIDs, are surprisingly effective for some cancer pain, and may avoid the problems of dependence and waning opioid analgesia over time,” said co-author Jane Ballantyne, MD, a retired anesthesiologist and professor at the University of Washington.

Ballantyne is Vice President of Clinical Affairs for Physicians for Responsible Opioid Prescribing (PROP), an anti-opioid activist group that advised the CDC during the drafting of its controversial 2016 opioid guideline. Like several other PROP members, Ballantyne has worked as a paid expert witness for law firms involved in opioid litigation.

This is not the first time Ballantyne has said that opioids should be used more cautiously when cancer patients are not terminally ill. In 2007, she wrote an op/ed saying that cancer treatment and survival rates had improved so much that opioids should no longer be viewed as the go-to treatment for cancer pain.  

“Cancer was once an explosive, typically terminal disease and became the prototype for end-of-life opioid pain treatment. However, cancer is no longer such an explosive disease, and many cancer sufferers can now expect to have a prolonged, even normal, lifespan. They may need pain treatment, but this treatment should not be modeled on palliative care paradigms,” Ballantyne wrote.

Many cancer patients are already struggling to get pain relief. A recent study found the number of cancer patients seeking treatment for pain in U.S. emergency departments has doubled in recent years. Nearly half of those ER visits were deemed preventable -- meaning they could have been avoided if the patient has received proper pain care earlier.

Other studies have documented how opioid prescriptions and doses have declined significantly for U.S. cancer patients. The Cancer Action Network warned there has been “a significant increase in cancer patients and survivors being unable to access their opioid prescriptions.” 

Are you a pain patient who has trouble getting your opioid prescriptions filled? There’s still time to take PNN’s survey on how opioid shortages are affecting patients at pharmacies. Click here to take the survey, which should only take a few minutes.