Opioids play an important role in how cancer patients manage pain, but the ongoing opioid epidemic has raised concerns about their potential for abuse.
Pain remains one of the most difficult symptoms associated with cancer. More than half of cancer patients undergoing treatment experience moderate to severe pain. Despite the accepted role of opioids in acute pain relief, the use of opioids for chronic pain (pain lasting longer three to six months) remains controversial. Chronic opioid use can lead to diminishing effectiveness as well as dependence, misuse, abuse, and unintentional overdosing.
With an estimated 16.9 million cancer survivors in the United States and two-thirds of newly diagnosed cancer patients living more than five years, many cancer researchers believe it's important to better understand opioid use in oncology patients. While there are guidelines for how to help cancer patients avoid opioid dependence, many researchers are concerned that recommendations for risk reduction are based on expert opinion not related to cancer patients specifically.
Within a cohort of 106,732 cancer survivors diagnosed between 2000 and 2015, researchers here determined rates of persistent post-treatment opioid use, diagnoses of opioid abuse or dependence, and admissions for opioid toxicity. This study cohort included patients diagnosed with one of the 12 most common cancers (bladder, breast, colon, esophagus, stomach, head and neck, kidney, liver, lung, pancreas, prostate, or rectal cancer), and alive without recurrence two years after treatment.
Among the patients in this study the overall incidence of persistent post-treatment opioid use was 8.3% which varied by cancer type ranging from a low of 5.3% in prostate cancer patients to a high of 19.8% in liver cancer patients. Bladder, breast, esophagus, stomach, head and neck, liver, lung and pancreas cancer were associated with higher odds compared to prostate cancer.
The rates of persistent opioid use after treatment varied substantially by a patient's history of opioid use prior to his receiving a cancer diagnosis. The persistent post-treatment opioid use rates were lowest for patients who had never used opioids prior to their cancer diagnosis (3.5%) followed by prior intermittent users (15.0%), and prior chronic users (72.2%). The rate of post treatment diagnoses of opioid abuse or dependence was 2.9%, and opioid-related admissions occurred in 2.1% of patients.
Several factors were associated with the risk of persistent opioid use. Younger age, white race, unemployment at the time of cancer diagnosis, lower median income, increased comorbidity, and current or prior tobacco use were all associated with increased risk for persistent opioid use. Prior diagnoses of alcohol abuse, non-opioid drug abuse, opioid abuse, and depression were associated with increased odds. Prior history of chronic opioid use and prior intermittent use were associated with substantially increased odds of persistent opioid use
"Our study attempts to create an objective clinical tool that can help give providers a better understanding of a patient's risk of opioid-related toxicity," said Lucas K. Vitzthum, an author of the study. "Ultimately, clinical tools such as ours could help providers identify which patients could benefit from alternative pain management strategies or referral to pain specialists."
James D. Murphy, another author, noted that "opioids play an important role in helping patients with pain from cancer, or pain because of treatment. Despite this important role, opioid use carries a risk of problems related to long-term use, or abuse. From a healthcare provider perspective, we need better approaches to identify cancer patients at risk of these opioid-related problems."