The Efficacy and Adverse Events in Patients with Head and Neck Cancer Following Radiotherapy Combined with S-1 Therapy: A Meta-Analysis

SIMPLE SUMMARY: Head and neck squamous cell carcinoma (HNSCC) ranks sixth among the most common cancers, accounting for approximately 3.3% of all cancer cases. While HNSCC was generally treated with postoperative concurrent chemo-radiotherapy, traditional chemotherapy agents often lead to multiple side effects. On the other hand, continuous loss dose oral metronomic chemotherapy, such as S-1, maintains good anticancer activity and involves fewer side effects. While several studies have been undertaken on metronomic chemotherapy in head and neck cancer (HNC) during the last decade, results have often been contradictory. We addressed the contradictory literature with a meta-analysis to summarize the available evidence on the efficacy of S-1 chemotherapy combined with radiotherapy for patients with head and neck cancer and the adverse effects associated with the therapy. ABSTRACT: This meta-analysis was conducted to assess the efficacy and adverse events associated with S-1 chemotherapy combined with radiotherapy for patients with head and neck cancer. The PubMed, Embase, and Cochrane Library databases were searched up to 10 February 2021. Eligible studies included clinical trials using S-1 chemotherapy combined with radiotherapy for head and neck cancer patients that measured tumor response, local control rate, overall survival, and grade 3/4 adverse events. A meta-analysis was performed using a random effects model. Twelve trials involving 378 patients met the selection criteria. The objective response and clinical benefit rate (complete/partial response and stable disease) of S-1 chemotherapy with radiotherapy were 86.3% (95% confidence interval (CI), 60.3–96.3) and 88.3% (95% CI, 70.1–96.1), respectively. The median 3-year local control rate, 3-year overall survival rate, and grade 3/4 adverse event rate were 84.0% (95% CI, 71.4–91.7), 69.6% (95% CI, 54.9–81.1), and 42.0% (95% CI, 36.2–48.0), respectively. S-1 combined with radiotherapy for patients with head and neck squamous cell carcinoma results in a good tumor response, favorable survival rate, and low toxicity. A prospective randomized, double-blind trial is required to assess the efficacy and safety of S-1 combined with radiotherapy to treat HNSCC.