Background

Current lymph node (LN) staging for Merkel cell carcinoma (MCC) does not account for the number of metastatic LNs, which is a primary driver of survival in multiple cancers.

Objective

To determine the impact of the number of metastatic LNs on survival in MCC.

Methods

Patients with MCC undergoing surgery were identified from the National Cancer Database (NCDB). The association between metastatic LN number and survival was modeled with restricted cubic splines. A novel nodal classification system was derived by using recursive partitioning analysis. MCC patients undergoing surgery in the Surveillance, Epidemiology, and End Results (SEER) Program were used as validation cohort.

Results

Among 3670 patients in the NCDB, increasing metastatic LN number was associated with decreased survival (P < .001). Mortality risk increased continuously with each additional positive LN when using multivariable, nonlinear modeling. According to a novel staging system derived via recursive partitioning analysis, the hazard ratio for death in multivariable regression compared with patients without LN involvement was 1.24 (P = .049), 2.08 (P < .001), 3.24 (P < .001), and 6.13 (P < .001) for the proposed N1a (1-3 metastatic LNs with microscopic detection), N1b (1-3 metastatic LNs with macroscopic detection), N2 (4-8 metastatic LNs), and N3 (≥9 metastatic LNs), respectively. This system was validated in the SEER cohort and showed improved concordance compared with the American Joint Committee on Cancer, Eighth Edition.

Limitations

Retrospective design.

Conclusions

Number of metastatic LNs is the dominant nodal factor driving survival in patients with MCC.

中文翻译：

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Merkel 细胞癌的定量转移性淋巴结负荷和存活率。

背景

目前默克尔细胞癌 (MCC) 的淋巴结 (LN) 分期没有考虑转移性淋巴结的数量，后者是多种癌症存活的主要驱动因素。

客观的

确定转移性淋巴结数量对 MCC 存活率的影响。

方法

接受手术的 MCC 患者是从国家癌症数据库 (NCDB) 中确定的。转移性 LN 数量和存活率之间的关联用受限三次样条建模。通过使用递归分区分析推导出一种新的节点分类系统。在监测、流行病学和最终结果 (SEER) 计划中接受手术的 MCC 患者被用作验证队列。

结果

在 NCDB 的 3670 名患者中，转移性 LN 数量的增加与生存率降低有关 ( P  < .001)。使用多变量非线性建模时，每增加一个正 LN，死亡率风险就会不断增加。根据通过递归分区分析得出的新分期系统，与没有 LN 受累的患者相比，多变量回归中的死亡风险比为 1.24 ( P  = .049)、2.08 ( P  < .001)、3.24 ( P  < .001) , 和 6.13 ( P < .001) 分别用于建议的 N1a（1-3 个具有显微检测的转移性 LN）、N1b（1-3 个具有宏观检测的转移性 LN）、N2（4-8 个转移性 LN）和 N3（≥9 个转移性 LN） . 该系统在 SEER 队列中得到验证，与美国癌症联合委员会第八版相比显示出更高的一致性。

限制

回顾性设计。

结论

转移性淋巴结的数量是推动 MCC 患者生存的主要淋巴结因素。