Cancer Patients 10 Times Less Likely To Die From Overdose

Anesthesiology News

Cancer patients are 10 times less likely to have opioid overdose listed as the primary cause of death than the general population, but rates of opioid-related deaths are still rising in that population.

“Many patients are fearful of taking opioids for cancer-related pain, given concerns for opioid overdose driven by news of the opioid epidemic,” said Fumiko Chino, MD, a radiation oncology intern in the Duke Cancer Institute at Duke University School of Medicine, in Durham, N.C., who presented an analysis of national data at the 2018 American Society of Clinical Oncology Quality Care Symposium (abstract 230). “Our research provides some reassurance that opioid-related deaths in the cancer patient population are much rarer than in the general population.”

Up to 50% of cancer patients experience moderate to severe cancer-related pain. Opioids are a mainstay of treatment for them; however, restrictions on prescribing have reduced access. The morphine equivalent daily dosage was cut by almost half from 2010 to 2015 in one study of patients referred to an outpatient palliative care clinic (J Oncol Pract 2017;13[12]:e972-e981). Opioid prescriptions for cancer survivors decreased by more than half between 2016 and 2018, according to the Opioid Access Research Project by the American Cancer Society Cancer Action Network and the Patient Quality of Life Coalition. Approximately half of those surveyed relayed that their physicians indicated treatment options were limited by laws, guidelines or insurance coverage.

“In practical terms, the volume of cancer patient overdose deaths is very small,” she said. “In the general population, the growth is exponential.”

Individuals who died from opioid-related deaths with cancer as a contributing cause were significantly older, more likely to be women, less likely to be single, and more likely to have at least a college degree. They also were slightly less likely to be white and slightly more likely to be non-Hispanic.

Opioid deaths were disproportionate among patients with lung cancer, which accounted for 13.5% of new diagnoses but 22.3% of opioid-related deaths, and head and neck cancer, which accounted for 3.7% of new diagnoses but 11.7% of opioid-related deaths. “This highlights a potential discrepancy, or disconnect, about the importance of opioid risk assessments and close monitoring for certain patient populations,” Dr. Chino said.

She acknowledged some limitations of the analysis, which depends on accurate opioid-related death counts and relies on cancer being listed as a contributing cause—when present. Such analyses may overestimate concerns for opioid-related deaths due to subtleties lost in intentional deaths involving opioids in death with dignity states. They could also underestimate them, as providers may assume all deaths in cancer patients are due to cancer and not overdose.

Opioid-related deaths among persons with cancer are not rising at the rapid rate seen in the general population, but they have risen slightly over the last decade. “This may be due to increased survivorship, so we’re doing our jobs better—we’re saving more lives—but we’re also potentially increasing the rates of chronic pain,” she said.

The recent passage of death with dignity laws in several states also may have increased rates of opioid overdose, or the increase could simply be “spillover from the opioid crisis,” greater availability of opioids outside the medical environment, or the coincidence of cancer-related pain and opioid abuse disorder, she suggested.

David Hui, MD, an associate professor of palliative care and rehabilitation medicine at University of Texas MD Anderson Cancer Center, in Houston, maintained that cancer patients may be at risk for opioid misuse because of greater exposure to the drugs, greater prevalence of risk factors (i.e., those underlying their disease, such as alcohol and smoking), and psychological distress. Studies, however, have been inconsistent on this issue, with prevalence rates for misuse ranging from 0% to 18%.

Dr. Hui said the study presented by Dr. Chino was reassuring in several ways: It showed trends that were relatively consistent with other studies in noncancer populations; lung cancer and head and neck cancer were more common among patients with opioid-related deaths, which is consistent with known risk factors; and the results were consistent with a Veterans Affairs study that found cancer patients to be at a lower risk for opioid overdose deaths (0.25% vs. 0.56%) (JAMA 2011;305[13]:1315-1321).

But “ascertainment bias” could be a limiting factor, he indicated. The results were dependent on the quality of death certificate completion; it is possible that when opioid overdose and cancer co-occur they are not both coded. Persons dying of cancer—even with overdose—are likely to have cancer listed as the cause of death. The study also did not differentiate between nonprescription versus prescription opioids, and between intentional versus accidental overdoses.

Nevertheless, the study found that cancer patients are more than 10 times less likely to die of opioid overdose, possibly because they are older, are receiving the drugs for an evidence-based indication, are regularly monitored by physicians, have greater access to psychological support and palliative care, and have a competing risk for mortality (i.e., cancer).