Does the use of Marijuana Impact Outcomes in Patients with Squamous Cell Carcinoma of the Oropharynx?

Abstract

The incidence of human papilloma virus (HPV) associated oropharyngeal squamous cell carcinoma (OP-SCC) has increased significantly in the past few years. While many of these patients do not abuse tobacco products, they may use marijuana in various forms. The impact of marijuana use/ abuse on survival and local control in head and neck cancer patients is not well understood. The purpose of our analysis was to evaluate the management and outcomes in our patients treated for OP-SCC stratified according to marijuana use. After obtaining Institutional Review Board (IRB) we used our institutional database of 360 patients with detailed psychosocial and substance abuse history to identify patients with OP-SCC. Clinico-pathological data and treatment details were compared between marijuana users vs. non-users. Using Kaplan-Meier curves and log-rank test were evaluated overall (OS), disease free (DFS), distant metastases free (DMFS) and locoregional free (LRFS) survival based on Marijuana use. We identified 74 patients with OP-SCC of which 62 (84%) were male, 55 (74%) were Caucasians and 52 (70%) were HPV+ve. Median age was 62 years (range: 41-71) and 61% were ever-smokers with median pack/year of 25.5. Radical surgery was undergone in 17 (23%), whereas, the rest 57 (77%) were treated by definitive chemoradiotherapy. Marijuana users encompassed 35% of the study cohort (n=26) and non-users were 65% (n=48). Clinicopathological details not differ between the study groups. In addition, marital status, highest educational level, alcohol use and smoking history were similar. Marijuana users underwent marginally less surgeries (11.5 vs 29.2%; p=0.085), had higher median pain score (7 vs. 6) and more mean weight loss during radiotherapy (22.2 vs 18.5 Lb.), albeit nothing was significant (p>0.05). Although LRFS (p=0.12) and DMFS (p=0.48) did not differ between users vs. non-users; marijuana use was marginally detrimental for DFS (1-year 69% vs. 77% and 3-years: 27% vs. 70%: p=0.051) and was associated with significantly worse OS (1-year: 60% vs. 82% and 3-years: 30% vs. 73%; p=0.005). Marijuana use was not associated with disease specific features. Nevertheless, there seems to be a significant impact of the use of marijuana and the adherence to RT, quality of life, and overall survival. A more detailed analysis is underway to better understand the impact of various psycho-social factors on RT treatment tolerance.