This study evaluated the evidence for adjuvant radiation therapy in Merkel cell carcinoma, analyzing its impact on local recurrence, regional control, and overall survival. The review synthesized data from multiple studies to assess when adjuvant radiation provides benefit beyond surgery alone, considering factors such as tumor size, margin status, and nodal involvement.

Adjuvant radiation reduces local and regional recurrence in MCC, particularly for tumors with positive or close margins.

The benefit of adjuvant radiation is most pronounced for primary tumors >2 cm and those with nodal involvement.

Radiation field and dose protocols for MCC remain variable across institutions, highlighting the need for standardized guidelines.