OBJECTIVES : There is growing awareness of opioid use in cancer survivors as the population increases. Neither opioid dose utilization pre- and post-curative intent radiation (CIR) or the factors associated with opioid doses is known. Objectives were to determine opioid oral morphine equivalent (OME) doses for cancer survivors after CIR and factors associated with higher opioid dose burden.

METHODS : Electronic medical record clinical and pharmacy data from cancer survivors receiving radiotherapy for any indication from a single academic cancer center from January 1, 2008 to December 31, 2018 were utilized to calculate OME doses before and after CIR. A panel data model was used to estimate factors associated with high opioid doses and a mixed linear model was used to predict average opioid dose used one year after CIR. Subgroup and sensitivity analyses were then conducted.

RESULTS : Cancer survivors that had an opioid prescription prior to radiation were estimated to have, on average, 68.2 (95% CI: 62.8-73.6, panel data model) - 68.3 (95% CI: 62.9-73.7, mixed linear model) OMEs higher that those without an opioid prescription prior to radiation over the course of time, controlling for other factors. Across models and subgroups, patients with public insurance and comorbid conditions of anxiety, depression, and other drug use were associated with higher average OMEs over time, while patients with diabetes and hypertension were associated with lower average OMEs over time. Controlling for other factors, we predict that patients that undergo radiation for their cancer will use, on average, 4.1 (95% CI: 3.1-5.1) OMEs one year after CIR.

CONCLUSIONS : From this study, for many cancer survivors utilizing opioids long-term before or after radiation, sustained high doses of opioids were used.