Efficacy Of Medical Cannabis For Cancer-Related Pain In The Elderly: A Single-Center Retrospective Analysis.

13 Background: Use of medical cannabis (MC) for cancer-related symptoms is growing, yet many prior studies used formulations not available in the United States (US). Clinical data on formulation, dosing and efficacy for formulations available in the US is limited. Furthermore, though interest is growing in the use of MC for elderly patients, data on safety and efficacy in this population is limited. We aimed to assess the clinical characteristics of elderly people using MC, formulations prescribed, and efficacy for cancer-related pain, insomnia and anxiety. Methods: We conducted a retrospective chart review of patients age 65 and older prescribed MC in the year 2018 in an outpatient palliative care clinic at a tertiary comprehensive cancer center. Pain intensity and anxiety were measured by numerical rating (0-10), and insomnia was assessed by self-reported hours of sleep per night, with data collected at consecutive clinic visits before and after MC use. Results: Eighty-three patients aged 65 and over were included in our analysis. Half of patients were age 65-70, while 12% were age 76 or older. Slightly more than half were male (58%), while the majority were Caucasian (92%). For patients with pain, two thirds were already prescribed opioids; 28% were using gabapentin/pregabalin, 22% duloxetine, and 7% nortriptyline/amitriptyline. Two-thirds (65%) reported never using cannabis previously. The most common MC product used was oil (35%), followed by vape (13%), pill (6%) and powder (3%). The most common initial concentrations were equal THC/CBD (41%) and high THC (43%); 8% of patients used high CBD, and 8% used a combination. The median delta pain score did not change with use of MC (delta pain = 0.0, p = 0.72), nor did anxiety (delta anxiety = -0.2, p = 1.00) nor insomnia (delta hours sleep = -0.1, p = 1.000). Conclusions: In this study of elderly patients prescribed MC, the majority of whom were cannabis naïve and already prescribed opioids, most were initially prescribed high THC or 1:1 THC/CBD, with oil and vape the most common formulations used. Use of MC was not associated with changes in pain, anxiety nor insomnia scores.