Impact of adjuvant radiotherapy in squamous cell carcinoma of the oral cavity with perineural invasion

Objective: Current guidelines indicate postoperative radiotherapy (PORT) in oral squamous cell carcinoma (OSCC) with perineural invasion (PNI), however, its real benefit has never been proven. The aim of our study is to investigate the benefit of PORT in OSCC patients with PNI in terms of survival and disease control. Data sources: The Pubmed/MEDLINE, Cochrane Library, and Scopus databases. Review methods: Patients with PNI + OSCC treated with primary surgery were extracted from the included studies. The pooled logHR was calculated by comparing patients who underwent PORT to those who underwent only observation for overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), and locoregional control (LRC). Results: About 690 patients with primary OSCC and PNI were included from nine studies. 374 (54.2%) patients underwent PORT, while 316 (45.8%) underwent observation. Analyses showed non-significant difference between the two groups for OS (HR: 1.01; 95% CI: 0.38-2.69), DSS (HR: 2.03; 95% CI: 0.54-7.56), and LRC (HR: 0.89; 95% CI: 0.53-1.50). They showed a significant difference in terms of DFS (HR: 0.86; 95% CI: 0.77-0.97). Conclusion: The real benefit of PORT in OSCC patients with PNI is still unclear, although it may have a positive impact on DFS. Clinicians should consider individual patient's characteristics, tumor factors, and treatment goals when deciding whether to recommend PORT. Further studies are needed to clarify which entity of PNI really benefits from PORT. Level of evidence: NA Laryngoscope, 134:2019-2027, 2024.