Reduced-dose radiation in human papillomavirus-associated oropharyngeal carcinoma can improve outcome: a systematic review and meta-analysis

BACKGROUND: Despite its effectiveness, the standard course of chemoradiation for the treatment of human papillomavirus (HPV)-related oropharyngeal carcinoma (OPC) results in considerable treatment-related adverse effects. Studies proved that HPV-positive OPC is very sensitive to radiotherapy. Using de-escalation therapy as a new strategy is critical to maintaining positive outcomes while alleviating side effects. However, some studies hold that reduced dose causes insufficient effect on tumor killing. We conducted this systematic review and meta-analysis of survival and adverse reactions in patients with HPV-related OPC by retrospective analysis and evaluated the therapeutic effect of reducing the radiation dose. METHODS: Data were double-selected and extracted by searching seven electronic databases, Original studies in all language treated HPV-associated OPC with reduced-dose and standard-dose therapies were included. Overall survival (OS), progression-free survival (PFS), and incidence rates of adverse events were obtained by pooling analyses. Statistical analyses were performed using RStudio Version 1.1.383 (RStudio, Boston, MA, USA) via the Meta-Analysis R Package (metafor). Heterogeneity was evaluated using the I(2) statistic and the Cochran Q test. We used Stata (version 15.0) for forest graph. RESULTS: Thirteen studies were included in this meta-analysis, involving a dose range of 66–70 Gy for the standard treatment regimen and <66 Gy for the reduced-dose group. There was no significant difference in the age of the patients in the standard and the reduced treatment groups (60.9±5.9 vs. 58.6±2.4 years). Nine studies were included as standard cohort and thirteen studies were enrolled as reduced-dose cohort. The 2- and 3-year overall survival rates in the reduced-dose group (95.66% and 91.51%, respectively) were superior to those in the standard-dose group (88.36% and 87.46%, respectively). There was no significant difference in PFS between the two groups. A systematic review of articles on dose reduction and the standard dose was also conducted. The most common complication in reduced-dose radiation was oral mucositis (36.4%), followed by decreased white blood cell (WBC) count (30.5%) and dry mouth (29.1%). CONCLUSIONS: Reducing the radiation dose in patients with HPV-related OPC substantially alleviates the treatment toxicities and optimizes the quality of life of patients while at the same time maintaining favorable oncologic outcomes.