A systematic review: is contralateral elective neck dissection or neck radiotherapy indicated in lateralised cT3/T4 N0 oral squamous cell carcinoma?

Introduction Contralateral cervical lymph node metastasis remains a therapeutic challenge in patients with lateralised T3/T4 N0 oral squamous cell carcinoma (OSCC), with current guidelines offering differing recommendations regarding management of the contralateral neck. Methods A systematic review was conducted in accordance with PRISMA. MEDLINE and Embase were searched from January 2008 to March 2026 for studies evaluating contralateral neck management in lateralised T3/T4 N0 OSCC. Risk of bias was assessed using ROBINS-I and QUADAS-2, according to study design. Where possible, a meta-analysis was undertaken by combining outcome measures, otherwise due to anticipated heterogeneity a narrative synthesis was used. Results Search of the databases revealed 10,670 articles, following deduplication 5,173 were screened and 23 articles were sought for retrieval. Thirteen studies were included, involving 2,764 patients, predominantly retrospective cohorts; 561 were clearly identified as well lateralised T3N0 or T4N0. The tongue was the most common tumour subsite. A random-effects meta-analysis of proportions demonstrated a pooled contralateral neck disease rate of 16.1% (95% CI 1.2–51.7%), the 95% prediction interval was 0.1–90.3%, indicating substantial between-study heterogeneity (I² = 93.5%). Available studies did not provide sufficient evidence to determine whether elective contralateral neck treatment improves locoregional control, disease-free survival or cancer specific survival compared with observation. Interpretation was limited by retrospective study designs, heterogeneity and potential confounding. Sentinel lymph node biopsy and lymphoscintigraphy-guided approaches may help identify selected patients at risk of contralateral disease, although evidence in advanced tumours remains limited. Discussion Overall, the current evidence is insufficient to support or oppose routine elective contralateral neck dissection or radiotherapy in lateralised T3/T4 N0 OSCC. Selective lymphatic mapping may support more individualised management, but prospective validation is required before its routine use. Systematic review registration https://www.crd.york.ac.uk/prospero/ , identifier CRD420261499193.