Association of Marijuana Use With Psychosocial and Quality of Life Outcomes Among Patients With Head and Neck Cancer.

Importance: Cannabis sativa, the most widely used illicit substance in Canada, has a unique ability to facilitate relaxation and relieve anxiety while reducing pain. However, no study to date has examined quality of life (QOL) and psychosocial issues in relation to the use of this drug among patients with newly diagnosed head and neck cancer (HNC).

Objective: To examine the differences in QOL and psychosocial outcomes between marijuana users and nonusers with newly diagnosed HNC.

Design, Setting, and Participants: This prospective cohort study was conducted at a tertiary care cancer center. Patients were enrolled consecutively and prospectively at the time of HNC diagnosis from January 1, 2011, to January 1, 2015. Seventy-four patients who were current marijuana users were case matched to 74 nonusers in a 1:1 scheme based on age, sex, and tumor subsite. All patient demographic and QOL data were collected prospectively, and data analysis was conducted from November 1 to December 1, 2017.

Main Outcomes and Measure: The QOL outcome was assessed using the EuroQol-5D (EQ5D) and the Edmonton Symptom Assessment System (ESAS) questionnaires.

Results: A total of 148 patients were included in this study: 74 in the marijuana user group (mean [SD] age, 62.3 [10.3] years; male sex, 61 patients [82%]) and 74 in the marijuana nonuser group (mean age, 62.2 years; male sex, 63 patients [85%]). There was no statistically significant difference in age, sex, tumor subsite, clinical TNM staging, treatment modality, or mean Karnofsky score between the 2 groups. On univariate analysis, there was no statistically significant difference in the mobility, self-care, and usual activities domains of the EQ5D. Marijuana users had significantly lower scores in the anxiety/depression (difference, 0.74; 95% CI, 0.557-0.930) and pain/discomfort (difference, 0.29; 95% CI, 0.037-1.541) domains. Wilcoxon rank sum test confirmed the results of the EQ5D with improvements in the pain/discomfort (z score, -2.60) and anxiety/depression (z score, -6.71) domains. Marijuana users had less pain, were less tired, were less depressed, were less anxious, had more appetite, were less drowsy, and had better general well-being according to the ESAS. A Wilcoxon rank sum test confirmed a statistically significant improvement in ESAS scores within the domains of anxiety (z score, -10.04), pain (z score, -2.36), tiredness (z score, -5.02), depression (z score, -5.96), drowsiness (z score, -5.51), appetite (z score, -4.17), and general well-being (z score, -4.43).

Conclusions and Relevance: This prospective case-matched study suggests that there may be significant QOL benefits, including decreased anxiety, pain, and depression and increased appetite and generalized feelings of well-being, associated with marijuana use among patients with newly diagnosed HNC.