e15064 Background: Immune checkpoint inhibitors are used in treatment of advanced neoplasms. Immunotherapy agents create a potent pro-inflammatory effect in cancer. The efficacy of immunotherapy may negatively be impacted by the use of anti-inflammatory agents. An anti-inflammatory effect of cannabinoids has been described in literature in several models. Recent data suggests a negative impact of cannabis on tumor response to immunotherapy. Methods: We retrospectively reviewed medical records of all patients with metastatic cancer who received at least 2 months of immune checkpoint inhibitors between August 2014 and August 2018. The patients were stratified by use of cannabis (cannabis vs non-cannabis users). Baseline patients’ characteristics were compared. Overall survival was estimated and compared between the two groups. An analysis was performed using analysis of variance, Student's t-test, correlation, chi-squared test, and logrank test. All data were analyzed with SPSS v. 26.0 and a p-value less than 0.05 was set to indicate statistical significance. Results: A total of 104 patients with advanced-stage malignancy met the inclusion criteria. The median age was 63.9±10.5 years, 48.1% males and 81.7% Caucasians. 41.3% of patients has lung adenocarcinoma, 20.3% has squamous cell carcinoma of the lung, 11.5% has squamous cell carcinoma of the head and neck and 26.9% have other tumor types. Twenty patients (19.2%) had brain metastasis and twenty-three patients (22.1%) had bone metastasis. Seventy patients (66.8%) received Nivolumab, and twenty-seven patients (26%) received Pembrolizumab. The mean duration of immunotherapy use was 10.2 months. Characteristics of patients were similar between the groups except for a higher prevalence of tobacco use in the cannabis group. Twenty-eight patients (26.9%) reported concomitant cannabis use during immunotherapy treatment, 23 were prescribed (dronabinol) and 5 used it recreationally (smoking marijuana/cannabis oil). Non-cannabis users had significantly longer overall survival (OS) compared to cannabis users (40 months vs 16 months, p = 0.004). Conclusions: This study shows significant association between the use of cannabis during immunotherapy treatment and worse OS. This can be explained by an anti-inflammatory effect of cannabis, which may decrease response to immune checkpoint inhibitors. This observation should be further investigated in randomized trials. Health care professionals should be aware of the potentially harmful effect of cannabis on cancer care.
Immune checkpoint inhibitors for esophageal squamous cell carcinoma: a narrative review
