Purpose Current staging systems for oral cavity cancers incorporate lymph node (LN) size and laterality, but place less weight on the total number of positive metastatic nodes. We investigated the independent impact of numerical metastatic LN burden on survival. Methods Adult patients with oral cavity squamous cell carcinoma undergoing upfront surgical resection for curative intent were identified in the National Cancer Data Base between 2004 and 2013. A neck dissection of a minimum of 10 LNs was required. Multivariable models were constructed to assess the association between the number of metastatic LNs and survival, adjusting for factors such as nodal size, laterality, extranodal extension, margin status, and adjuvant treatment. Results Overall, 14,554 patients met inclusion criteria (7,906 N0 patients; 6,648 node-positive patients). Mortality risk escalated continuously with increasing number of metastatic nodes without plateau, with the effect most pronounced with up to four LNs (HR, 1.34; 95% CI, 1.29 to 1.39; P < .001). Extranodal extension (HR, 1.41; 95% CI, 1.20 to 1.65; P < .001) and lower neck involvement (HR, 1.16; 95% CI, 1.06 to 1.27; P < .001) also predicted increased mortality. Increasing number of nodes examined was associated with improved survival, plateauing at 35 LNs (HR, 0.98; 95% CI, 0.98 to 0.99; P < .001). In multivariable models accounting for the number of metastatic nodes, contralateral LN involvement (N2c status) and LN size were not associated with mortality. A novel nodal staging system derived by recursive partitioning analysis exhibited greater concordance than the American Joint Committee on Cancer (8th edition) system. Conclusion The number of metastatic nodes is a critical predictor of oral cavity cancer mortality, eclipsing other features such as LN size and contralaterality in prognostic value. More robust incorporation of numerical metastatic LN burden may augment staging and better inform adjuvant treatment decisions.

中文翻译：

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口腔癌的转移性淋巴结负担和生存率

目的 目前口腔癌的分期系统结合了淋巴结 (LN) 的大小和侧向性，但对阳性转移淋巴结的总数的重视程度较低。我们调查了数值转移性 LN 负担对生存的独立影响。方法 在 2004 年至 2013 年期间，在国家癌症数据库中确定了接受前期手术切除以达到治愈目的的口腔鳞状细胞癌成人患者。需要至少 10 个 LN 的颈部解剖。构建多变量模型以评估转移性 LN 数量与生存率之间的关联，调整淋巴结大小、偏侧性、结外延伸、边缘状态和辅助治疗等因素。结果 总体而言，14,554 名患者符合纳入标准（7,906 名 N0 患者；6,648 名淋巴结阳性患者）。死亡风险随着无平台期的转移性淋巴结数量的增加而持续升高，最多四个淋巴结时效果最明显（HR，1.34；95% CI，1.29 至 1.39；P < .001）。结外延伸（HR，1.41；95% CI，1.20 至 1.65；P < .001）和下颈部受累（HR，1.16；95% CI，1.06 至 1.27；P < .001）也预示死亡率增加。检查的结节数量增加与生存率提高相关，在 35 个 LN 处达到平台期（HR，0.98；95% CI，0.98 至 0.99；P < .001）。在考虑转移淋巴结数量的多变量模型中，对侧 LN 受累（N2c 状态）和 LN 大小与死亡率无关。通过递归分区分析得出的一种新型淋巴结分期系统比美国癌症联合委员会（第 8 版）系统具有更高的一致性。结论 转移性淋巴结的数量是口腔癌死亡率的关键预测因子，其预后价值超过了其他特征，如 LN 大小和对侧性。更稳健地结合数字转移性 LN 负担可能会增加分期并更好地为辅助治疗决策提供信息。