Background: The positive effect of radiation therapy for patients with advanced oropharyngeal squamous cell carcinoma (OSCC) has been substantially verified. The present work investigated whether a meta-analysis of current data is able to evaluate the effectiveness of postoperative radiotherapy (PORT) in patients with small OSCC (pT1, pT2) and a single ipsilateral lymph node metastasis (pN1).
Methods: The meta-analysis comprises randomized and non-randomized studies. High-risk tumors were excluded and defined by size ≥ pT3/pT4, lymph node involvement ≥ pN2, or presence of additional histological risk factors, e.g., involved positive resection margins, extra nodal spread of the disease, or lymphangiosis carcinomatosa. The primary outcome analyzed mortality between the different treatment arms.
Results: Only one prospective randomized clinical trial and six retrospective observational studies were adequate for evaluation. Descriptive analysis revealed a marginally higher mortality in the irradiation group (44% vs. 34%). In contrast, a forest plot presentation of two of seven studies with and without events in the control and therapy arms presented an advantage for the irradiation group with the limitation of large heterogeneity and a lack of statistical significance.
Conclusion: Present data are poor and exhibit limited internal and external validity; thus, direct comparison was not possible with the eligible studies. Therefore, a meta-analysis of present data may not serve as the basis for a general treatment recommendation but underlines the need of prospective, randomized, controlled clinical trials.