Prevalence and implications of bilateral and solely contralateral lymph node metastases in oral squamous cell carcinoma

Abstract

Abstract Objectives Effective management of neck in oral squamous cell carcinoma (OSCC) is pivotal for oncological outcomes. Although consensus exists for ipsilateral neck dissection (ND), the necessity for contralateral ND remains controversial. This study aimed to assess the prevalence and implications of bilateral/solely contralateral (B/SC) lymph node metastases (LNMs) to determine the need for contralateral elective ND. Additionally, it examined the prevalence and implications of occult B/SC metastases. Materials and methods In a retrospective cohort study, 420 OSCC patients underwent primary surgical treatment following German guidelines at a tertiary center. Preoperative contrast-enhanced computed tomography was conducted, and ND adhered to a standardized approach. Results Solely contralateral metastases occurred in 0.95% of patients, with bilateral metastases observed in 7.13%. Occult B/SC metastases occurred in 3.81% of the cases. Correlation analysis revealed a statistically significant association between B/SC metastases and higher tumor stages, tumor localization at the upper jaw or floor of the mouth, proximity to the midline, ipsilateral LNMs, and lymphatic invasion (all p < 0.05). Patients with B/SC metastases showed poorer disease-free survival, with statistical significance reached in the bilateral LNMs group (p = 0.010). Similarly, a significant difference was noted in overall survival between patients with bilateral and solely ipsilateral metastases (p = 0.044). Conclusions B/SC LNMs are rare in patients with OSCC, especially in those who present with clinico-radiologically negative ipsilateral necks. Higher rates of B/SC metastases occur in case of advanced tumors and those localized at the upper jaw or floor of the mouth. Ipsilateral LNMs significantly elevate the risk of contralateral LNMs, tripling the associated risk. Clinical relevance These findings provide valuable insights for surgeons considering contralateral ND or extended adjuvant treatment for OSCC patients. However, the absence of high-level evidence from randomized controlled trials impedes the establishment of a definitive standard of care.