Taking opioids to manage pain could lead to addiction and chronic use among cancer survivors, shows study
Cancer survivors, who take opioids for managing their pain, can get addicted to them. According to an analysis by researchers from the University of California, San Diego, 8.3% of survivors were chronic opioid users after treatment, and 2.9% were diagnosed with opioid abuse or dependence. Opioid-related admissions occurred in 2.1% of patients, says the research team.
For their study, the researchers 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. The patients were alive without recurrence two years after treatment.
The rates of persistent opioid use after treatment varied substantially depending on the cancer-type - bladder, breast, esophagus, stomach, head and neck, liver, lung, and pancreas cancer were associated with higher odds compared to prostate cancer. This rate ranged from a high of 19.8% in liver cancer patients to a low of 5.3% in prostate cancer patients.
The use of chemotherapy was a risk factor, and it was associated with an increased risk of chronic opioid use, opioid abuse, and opioid toxicity.
Opioids play a crucial role in how cancer patients manage pain, but the ongoing opioid epidemic has raised concerns about their potential for abuse.
"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," says study author James D. Murphy from the Department of Radiation Medicine and Applied Sciences, University of California.
Pain remains one of the most feared and difficult symptoms associated with cancer. More than half of cancer patients undergoing treatment experience moderate to severe pain, warranting opioid use. However, say experts, despite the accepted role of opioids in acute pain relief, the use of opioids for chronic pain -- lasting longer than three to six months -- remains controversial. Chronic opioid use can lead to diminishing effectiveness as well as dependence, misuse, abuse, drug diversion, and unintentional overdosing, says the team.
Accordingly, says the research team, with an estimated 13.7 million cancer survivors in the US and two-thirds of newly diagnosed cancer patients living more than five years, a better understanding of persistent opioid use, abuse, and toxicity in oncology patients is critical.
While there are guidelines on 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.
"Optimal pain management with opioids requires a patient-specific assessment of benefits and risks. Along these lines, the American Society of Clinical Oncology (ASCO) recommends a risk-stratified approach to pain management and prescribing opioids. Specific risk mitigation strategies include adherence monitoring, drug screening, alternative pain management strategies, judicious opioid use, and referral to pain specialists. Current guidelines for risk stratification, however, are based on expert opinion or instruments validated in non-oncology cohorts - that may omit risk factors relevant to cancer patients," says the study published in the Journal of the National Cancer Institute.
The study involved 106,732 cancer survivors diagnosed between 2000 and 2015. The researchers determined rates of persistent post-treatment opioid use, diagnoses of opioid abuse or dependence, and admissions for opioid toxicity.
"Among the 106,732 cancer survivors 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. The rate of post-treatment diagnoses of opioid abuse or dependence was 2.9%, and opioid-related admissions occurred in 2.1% of patients," the findings state.
The rates of persistent opioid use after treatment also varied considerably by a patient's history of opioid use before receiving a cancer diagnosis, with prior chronic users at the highest risk. The persistent post-treatment opioid use rates were lowest for patients who had never used opioids before their cancer diagnosis (3.5%) followed by prior intermittent users (15.0%), and prior chronic users (72.2%).
Among those who never used opioids prior to diagnosis, the rates of opioid use varied by whether patients received opioids during the diagnostic and treatment period. "Those prescribed an opioid during the diagnostic and treatment period had rates of persistent post-treatment use of 6.2% compared to 1.5% of those that did not receive a prescription," shows analysis.
The team identified multiple factors that increased the risk of continued 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 linked with increased odds. Prior history of chronic opioid use and prior intermittent use were associated with substantially increased odds of persistent opioid use," says the study.
According to study author Lucas K. Vitzthum from the University of California, the current work attempts to create an "objective clinical tool" that can help give providers a better understanding of a patient's risk of opioid-related toxicity.
"Ultimately, clinical tools such as ours could help providers identify which patients could benefit from alternative pain management strategies or referral to pain specialists," says Vitzthum.