The use of Tetrahydrocannabinol (THC) is associated with an increase in survival time in palliative cancer patients: A retrospective multi-center cohort study.

Introduction: Tetrahydrocannabinol (THC) is often prescribed for ambulatory palliative patients to improve sleep quality and appetite and to reduce anxiety, stress, and pain. However, it is not known if THC has also an effect on the mortality of these patients. Method: The objective is the impact of THC on mortality of ambulatory palliative patients. For this purpose, data from the palliative treatment documentation from 5 ambulatory palliative care teams in Brandenburg, Germany were used for this analysis. Survival time was calculated for 3 groups of patients: 1) Without THC; 2) with THC in a low dosage (4.7 mg per day); and 3) THC in higher doses (>4.7 mg per day). The analysis was done for two cohorts of patients. Cohort 1: all patients with a survival time of at least 7 days after inclusion in specialized ambulatory palliative care (SAPC) and cohort 2: a sub-group of patients with a survival time between 7 and 100 days. Kaplan Meier curves were created, and multivariate analysis was done to investigate the impact of THC on mortality. Results: A total of 9419 patients with a survival time of at least 7 days after inclusion in SAPC were included in the analysis (cohort 1). 7085 among them had a survival time between 7 and 100 days (cohort 2). In both cohorts, survival time was significantly prolonged by THC, but only when the daily THC dose was above the median of 4.7 mg. Survival time was 15 days longer in cohort 2 (40 vs. 25 days), when more than 4.7 mg THC were prescribed per day. Conclusion: Use of THC is associated with a a significant increase in survival time in ambulatory palliative patients which survive longer than 7 days the initiation of THC prescription and which use of THC >4.7 mg/d.