Completion Lymph Node Dissection or Radiation Therapy for Sentinel Node Metastasis in Merkel Cell Carcinoma

Area of Science:

• Oncology
• Surgical Oncology
• Radiation Oncology

Background:

• Merkel cell carcinoma (MCC) with sentinel lymph node (SLN) metastasis presents a treatment dilemma regarding completion lymph node dissection (CLND) versus radiation therapy (RT).
• The comparative effectiveness of CLND and RT for SLN-positive MCC remains unclear.
• The prognostic significance of positive non-SLNs in this patient cohort requires further investigation.

Purpose of the Study:

• To compare outcomes between CLND and RT in MCC patients with SLN metastasis.
• To evaluate the prognostic impact of positive non-SLNs on survival and recurrence.
• To inform treatment decisions and identify high-risk groups for further therapeutic strategies.

Main Methods:

• A prospective database was utilized to identify MCC patients with SLN metastasis who underwent either CLND or RT.
• Treatment allocation was based on perioperative risk: CLND for low-risk, RT for high-risk patients.
• Key outcomes assessed included MCC-specific survival (MCCSS), disease-free survival (DFS), nodal recurrence-free survival (NRFS), and distant recurrence-free survival (DRFS).

Main Results:

• No significant differences in MCCSS, DFS, NRFS, or DRFS were observed between CLND and RT groups.
• Patients with positive non-SLNs demonstrated significantly worse MCCSS, DFS, and DRFS compared to those with negative non-SLNs.
• Multivariate analysis confirmed positive non-SLNs as an independent predictor of poorer MCCSS, DFS, and DRFS.

Conclusions:

• CLND and RT appear to yield comparable outcomes for SLN-positive MCC when aligned with institutional risk-based protocols.
• Positive non-SLN status is a critical prognostic factor associated with adverse survival and increased distant recurrence.
• Patients with positive non-SLNs represent a high-risk group who may benefit from consideration in adjuvant systemic therapy clinical trials.